用于 Python 的 DynamoDB 示例 (B SDK oto3)

import boto3

# Create a DynamoDB client using the default credentials and region
dynamodb = boto3.client("dynamodb")

# Initialize a paginator for the list_tables operation
paginator = dynamodb.get_paginator("list_tables")

# Create a PageIterator from the paginator
page_iterator = paginator.paginate(Limit=10)

# List the tables in the current AWS account
print("Here are the DynamoDB tables in your account:")

# Use pagination to list all tables
table_names = []

for page in page_iterator:
    for table_name in page.get("TableNames", []):
        print(f"- {table_name}")
        table_names.append(table_name)

if not table_names:
    print("You don't have any DynamoDB tables in your account.")
else:
    print(f"\nFound {len(table_names)} tables.")

创建封装 DynamoDB 表的类。

from decimal import Decimal
from io import BytesIO
import json
import logging
import os
from pprint import pprint
import requests
from zipfile import ZipFile
import boto3
from boto3.dynamodb.conditions import Key
from botocore.exceptions import ClientError
from question import Question

logger = logging.getLogger(__name__)

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def exists(self, table_name):
        """
        Determines whether a table exists. As a side effect, stores the table in
        a member variable.

        :param table_name: The name of the table to check.
        :return: True when the table exists; otherwise, False.
        """
        try:
            table = self.dyn_resource.Table(table_name)
            table.load()
            exists = True
        except ClientError as err:
            if err.response["Error"]["Code"] == "ResourceNotFoundException":
                exists = False
            else:
                logger.error(
                    "Couldn't check for existence of %s. Here's why: %s: %s",
                    table_name,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
                raise
        else:
            self.table = table
        return exists


    def create_table(self, table_name):
        """
        Creates an Amazon DynamoDB table that can be used to store movie data.
        The table uses the release year of the movie as the partition key and the
        title as the sort key.

        :param table_name: The name of the table to create.
        :return: The newly created table.
        """
        try:
            self.table = self.dyn_resource.create_table(
                TableName=table_name,
                KeySchema=[
                    {"AttributeName": "year", "KeyType": "HASH"},  # Partition key
                    {"AttributeName": "title", "KeyType": "RANGE"},  # Sort key
                ],
                AttributeDefinitions=[
                    {"AttributeName": "year", "AttributeType": "N"},
                    {"AttributeName": "title", "AttributeType": "S"},
                ],
                ProvisionedThroughput={
                    "ReadCapacityUnits": 10,
                    "WriteCapacityUnits": 10,
                },
            )
            self.table.wait_until_exists()
        except ClientError as err:
            logger.error(
                "Couldn't create table %s. Here's why: %s: %s",
                table_name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return self.table


    def list_tables(self):
        """
        Lists the Amazon DynamoDB tables for the current account.

        :return: The list of tables.
        """
        try:
            tables = []
            for table in self.dyn_resource.tables.all():
                print(table.name)
                tables.append(table)
        except ClientError as err:
            logger.error(
                "Couldn't list tables. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return tables


    def write_batch(self, movies):
        """
        Fills an Amazon DynamoDB table with the specified data, using the Boto3
        Table.batch_writer() function to put the items in the table.
        Inside the context manager, Table.batch_writer builds a list of
        requests. On exiting the context manager, Table.batch_writer starts sending
        batches of write requests to Amazon DynamoDB and automatically
        handles chunking, buffering, and retrying.

        :param movies: The data to put in the table. Each item must contain at least
                       the keys required by the schema that was specified when the
                       table was created.
        """
        try:
            with self.table.batch_writer() as writer:
                for movie in movies:
                    writer.put_item(Item=movie)
        except ClientError as err:
            logger.error(
                "Couldn't load data into table %s. Here's why: %s: %s",
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise


    def add_movie(self, title, year, plot, rating):
        """
        Adds a movie to the table.

        :param title: The title of the movie.
        :param year: The release year of the movie.
        :param plot: The plot summary of the movie.
        :param rating: The quality rating of the movie.
        """
        try:
            self.table.put_item(
                Item={
                    "year": year,
                    "title": title,
                    "info": {"plot": plot, "rating": Decimal(str(rating))},
                }
            )
        except ClientError as err:
            logger.error(
                "Couldn't add movie %s to table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise


    def get_movie(self, title, year):
        """
        Gets movie data from the table for a specific movie.

        :param title: The title of the movie.
        :param year: The release year of the movie.
        :return: The data about the requested movie.
        """
        try:
            response = self.table.get_item(Key={"year": year, "title": title})
        except ClientError as err:
            logger.error(
                "Couldn't get movie %s from table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Item"]


    def update_movie(self, title, year, rating, plot):
        """
        Updates rating and plot data for a movie in the table.

        :param title: The title of the movie to update.
        :param year: The release year of the movie to update.
        :param rating: The updated rating to the give the movie.
        :param plot: The updated plot summary to give the movie.
        :return: The fields that were updated, with their new values.
        """
        try:
            response = self.table.update_item(
                Key={"year": year, "title": title},
                UpdateExpression="set info.rating=:r, info.plot=:p",
                ExpressionAttributeValues={":r": Decimal(str(rating)), ":p": plot},
                ReturnValues="UPDATED_NEW",
            )
        except ClientError as err:
            logger.error(
                "Couldn't update movie %s in table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Attributes"]


    def query_movies(self, year):
        """
        Queries for movies that were released in the specified year.

        :param year: The year to query.
        :return: The list of movies that were released in the specified year.
        """
        try:
            response = self.table.query(KeyConditionExpression=Key("year").eq(year))
        except ClientError as err:
            logger.error(
                "Couldn't query for movies released in %s. Here's why: %s: %s",
                year,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Items"]


    def scan_movies(self, year_range):
        """
        Scans for movies that were released in a range of years.
        Uses a projection expression to return a subset of data for each movie.

        :param year_range: The range of years to retrieve.
        :return: The list of movies released in the specified years.
        """
        movies = []
        scan_kwargs = {
            "FilterExpression": Key("year").between(
                year_range["first"], year_range["second"]
            ),
            "ProjectionExpression": "#yr, title, info.rating",
            "ExpressionAttributeNames": {"#yr": "year"},
        }
        try:
            done = False
            start_key = None
            while not done:
                if start_key:
                    scan_kwargs["ExclusiveStartKey"] = start_key
                response = self.table.scan(**scan_kwargs)
                movies.extend(response.get("Items", []))
                start_key = response.get("LastEvaluatedKey", None)
                done = start_key is None
        except ClientError as err:
            logger.error(
                "Couldn't scan for movies. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

        return movies


    def delete_movie(self, title, year):
        """
        Deletes a movie from the table.

        :param title: The title of the movie to delete.
        :param year: The release year of the movie to delete.
        """
        try:
            self.table.delete_item(Key={"year": year, "title": title})
        except ClientError as err:
            logger.error(
                "Couldn't delete movie %s. Here's why: %s: %s",
                title,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise


    def delete_table(self):
        """
        Deletes the table.
        """
        try:
            self.table.delete()
            self.table = None
        except ClientError as err:
            logger.error(
                "Couldn't delete table. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

创建一个辅助函数来下载和提取示例JSON文件。

def get_sample_movie_data(movie_file_name):
    """
    Gets sample movie data, either from a local file or by first downloading it from
    the Amazon DynamoDB developer guide.

    :param movie_file_name: The local file name where the movie data is stored in JSON format.
    :return: The movie data as a dict.
    """
    if not os.path.isfile(movie_file_name):
        print(f"Downloading {movie_file_name}...")
        movie_content = requests.get(
            "https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/samples/moviedata.zip"
        )
        movie_zip = ZipFile(BytesIO(movie_content.content))
        movie_zip.extractall()

    try:
        with open(movie_file_name) as movie_file:
            movie_data = json.load(movie_file, parse_float=Decimal)
    except FileNotFoundError:
        print(
            f"File {movie_file_name} not found. You must first download the file to "
            "run this demo. See the README for instructions."
        )
        raise
    else:
        # The sample file lists over 4000 movies, return only the first 250.
        return movie_data[:250]

运行交互式场景以创建表并对其执行操作。

def run_scenario(table_name, movie_file_name, dyn_resource):
    logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")

    print("-" * 88)
    print("Welcome to the Amazon DynamoDB getting started demo.")
    print("-" * 88)

    movies = Movies(dyn_resource)
    movies_exists = movies.exists(table_name)
    if not movies_exists:
        print(f"\nCreating table {table_name}...")
        movies.create_table(table_name)
        print(f"\nCreated table {movies.table.name}.")

    my_movie = Question.ask_questions(
        [
            Question(
                "title", "Enter the title of a movie you want to add to the table: "
            ),
            Question("year", "What year was it released? ", Question.is_int),
            Question(
                "rating",
                "On a scale of 1 - 10, how do you rate it? ",
                Question.is_float,
                Question.in_range(1, 10),
            ),
            Question("plot", "Summarize the plot for me: "),
        ]
    )
    movies.add_movie(**my_movie)
    print(f"\nAdded '{my_movie['title']}' to '{movies.table.name}'.")
    print("-" * 88)

    movie_update = Question.ask_questions(
        [
            Question(
                "rating",
                f"\nLet's update your movie.\nYou rated it {my_movie['rating']}, what new "
                f"rating would you give it? ",
                Question.is_float,
                Question.in_range(1, 10),
            ),
            Question(
                "plot",
                f"You summarized the plot as '{my_movie['plot']}'.\nWhat would you say now? ",
            ),
        ]
    )
    my_movie.update(movie_update)
    updated = movies.update_movie(**my_movie)
    print(f"\nUpdated '{my_movie['title']}' with new attributes:")
    pprint(updated)
    print("-" * 88)

    if not movies_exists:
        movie_data = get_sample_movie_data(movie_file_name)
        print(f"\nReading data from '{movie_file_name}' into your table.")
        movies.write_batch(movie_data)
        print(f"\nWrote {len(movie_data)} movies into {movies.table.name}.")
    print("-" * 88)

    title = "The Lord of the Rings: The Fellowship of the Ring"
    if Question.ask_question(
        f"Let's move on...do you want to get info about '{title}'? (y/n) ",
        Question.is_yesno,
    ):
        movie = movies.get_movie(title, 2001)
        print("\nHere's what I found:")
        pprint(movie)
    print("-" * 88)

    ask_for_year = True
    while ask_for_year:
        release_year = Question.ask_question(
            f"\nLet's get a list of movies released in a given year. Enter a year between "
            f"1972 and 2018: ",
            Question.is_int,
            Question.in_range(1972, 2018),
        )
        releases = movies.query_movies(release_year)
        if releases:
            print(f"There were {len(releases)} movies released in {release_year}:")
            for release in releases:
                print(f"\t{release['title']}")
            ask_for_year = False
        else:
            print(f"I don't know about any movies released in {release_year}!")
            ask_for_year = Question.ask_question(
                "Try another year? (y/n) ", Question.is_yesno
            )
    print("-" * 88)

    years = Question.ask_questions(
        [
            Question(
                "first",
                f"\nNow let's scan for movies released in a range of years. Enter a year: ",
                Question.is_int,
                Question.in_range(1972, 2018),
            ),
            Question(
                "second",
                "Now enter another year: ",
                Question.is_int,
                Question.in_range(1972, 2018),
            ),
        ]
    )
    releases = movies.scan_movies(years)
    if releases:
        count = Question.ask_question(
            f"\nFound {len(releases)} movies. How many do you want to see? ",
            Question.is_int,
            Question.in_range(1, len(releases)),
        )
        print(f"\nHere are your {count} movies:\n")
        pprint(releases[:count])
    else:
        print(
            f"I don't know about any movies released between {years['first']} "
            f"and {years['second']}."
        )
    print("-" * 88)

    if Question.ask_question(
        f"\nLet's remove your movie from the table. Do you want to remove "
        f"'{my_movie['title']}'? (y/n)",
        Question.is_yesno,
    ):
        movies.delete_movie(my_movie["title"], my_movie["year"])
        print(f"\nRemoved '{my_movie['title']}' from the table.")
    print("-" * 88)

    if Question.ask_question(f"\nDelete the table? (y/n) ", Question.is_yesno):
        movies.delete_table()
        print(f"Deleted {table_name}.")
    else:
        print(
            "Don't forget to delete the table when you're done or you might incur "
            "charges on your account."
        )

    print("\nThanks for watching!")
    print("-" * 88)


if __name__ == "__main__":
    try:
        run_scenario(
            "doc-example-table-movies", "moviedata.json", boto3.resource("dynamodb")
        )
    except Exception as e:
        print(f"Something went wrong with the demo! Here's what: {e}")

此场景使用以下帮助程序类在命令提示符处提问。

class Question:
    """
    A helper class to ask questions at a command prompt and validate and convert
    the answers.
    """

    def __init__(self, key, question, *validators):
        """
        :param key: The key that is used for storing the answer in a dict, when
                    multiple questions are asked in a set.
        :param question: The question to ask.
        :param validators: The answer is passed through the list of validators until
                           one fails or they all pass. Validators may also convert the
                           answer to another form, such as from a str to an int.
        """
        self.key = key
        self.question = question
        self.validators = Question.non_empty, *validators

    @staticmethod
    def ask_questions(questions):
        """
        Asks a set of questions and stores the answers in a dict.

        :param questions: The list of questions to ask.
        :return: A dict of answers.
        """
        answers = {}
        for question in questions:
            answers[question.key] = Question.ask_question(
                question.question, *question.validators
            )
        return answers

    @staticmethod
    def ask_question(question, *validators):
        """
        Asks a single question and validates it against a list of validators.
        When an answer fails validation, the complaint is printed and the question
        is asked again.

        :param question: The question to ask.
        :param validators: The list of validators that the answer must pass.
        :return: The answer, converted to its final form by the validators.
        """
        answer = None
        while answer is None:
            answer = input(question)
            for validator in validators:
                answer, complaint = validator(answer)
                if answer is None:
                    print(complaint)
                    break
        return answer

    @staticmethod
    def non_empty(answer):
        """
        Validates that the answer is not empty.
        :return: The non-empty answer, or None.
        """
        return answer if answer != "" else None, "I need an answer. Please?"

    @staticmethod
    def is_yesno(answer):
        """
        Validates a yes/no answer.
        :return: True when the answer is 'y'; otherwise, False.
        """
        return answer.lower() == "y", ""

    @staticmethod
    def is_int(answer):
        """
        Validates that the answer can be converted to an int.
        :return: The int answer; otherwise, None.
        """
        try:
            int_answer = int(answer)
        except ValueError:
            int_answer = None
        return int_answer, f"{answer} must be a valid integer."

    @staticmethod
    def is_letter(answer):
        """
        Validates that the answer is a letter.
        :return The letter answer, converted to uppercase; otherwise, None.
        """
        return (
            answer.upper() if answer.isalpha() else None,
            f"{answer} must be a single letter.",
        )

    @staticmethod
    def is_float(answer):
        """
        Validate that the answer can be converted to a float.
        :return The float answer; otherwise, None.
        """
        try:
            float_answer = float(answer)
        except ValueError:
            float_answer = None
        return float_answer, f"{answer} must be a valid float."

    @staticmethod
    def in_range(lower, upper):
        """
        Validate that the answer is within a range. The answer must be of a type that can
        be compared to the lower and upper bounds.
        :return: The answer, if it is within the range; otherwise, None.
        """

        def _validate(answer):
            return (
                answer if lower <= answer <= upper else None,
                f"{answer} must be between {lower} and {upper}.",
            )

        return _validate

class PartiQLBatchWrapper:
    """
    Encapsulates a DynamoDB resource to run PartiQL statements.
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource


    def run_partiql(self, statements, param_list):
        """
        Runs a PartiQL statement. A Boto3 resource is used even though
        `execute_statement` is called on the underlying `client` object because the
        resource transforms input and output from plain old Python objects (POPOs) to
        the DynamoDB format. If you create the client directly, you must do these
        transforms yourself.

        :param statements: The batch of PartiQL statements.
        :param param_list: The batch of PartiQL parameters that are associated with
                           each statement. This list must be in the same order as the
                           statements.
        :return: The responses returned from running the statements, if any.
        """
        try:
            output = self.dyn_resource.meta.client.batch_execute_statement(
                Statements=[
                    {"Statement": statement, "Parameters": params}
                    for statement, params in zip(statements, param_list)
                ]
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ResourceNotFoundException":
                logger.error(
                    "Couldn't execute batch of PartiQL statements because the table "
                    "does not exist."
                )
            else:
                logger.error(
                    "Couldn't execute batch of PartiQL statements. Here's why: %s: %s",
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            raise
        else:
            return output

import decimal
import json
import logging
import os
import pprint
import time
import boto3
from botocore.exceptions import ClientError

logger = logging.getLogger(__name__)
dynamodb = boto3.resource("dynamodb")

MAX_GET_SIZE = 100  # Amazon DynamoDB rejects a get batch larger than 100 items.


def do_batch_get(batch_keys):
    """
    Gets a batch of items from Amazon DynamoDB. Batches can contain keys from
    more than one table.

    When Amazon DynamoDB cannot process all items in a batch, a set of unprocessed
    keys is returned. This function uses an exponential backoff algorithm to retry
    getting the unprocessed keys until all are retrieved or the specified
    number of tries is reached.

    :param batch_keys: The set of keys to retrieve. A batch can contain at most 100
                       keys. Otherwise, Amazon DynamoDB returns an error.
    :return: The dictionary of retrieved items grouped under their respective
             table names.
    """
    tries = 0
    max_tries = 5
    sleepy_time = 1  # Start with 1 second of sleep, then exponentially increase.
    retrieved = {key: [] for key in batch_keys}
    while tries < max_tries:
        response = dynamodb.batch_get_item(RequestItems=batch_keys)
        # Collect any retrieved items and retry unprocessed keys.
        for key in response.get("Responses", []):
            retrieved[key] += response["Responses"][key]
        unprocessed = response["UnprocessedKeys"]
        if len(unprocessed) > 0:
            batch_keys = unprocessed
            unprocessed_count = sum(
                [len(batch_key["Keys"]) for batch_key in batch_keys.values()]
            )
            logger.info(
                "%s unprocessed keys returned. Sleep, then retry.", unprocessed_count
            )
            tries += 1
            if tries < max_tries:
                logger.info("Sleeping for %s seconds.", sleepy_time)
                time.sleep(sleepy_time)
                sleepy_time = min(sleepy_time * 2, 32)
        else:
            break

    return retrieved

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def write_batch(self, movies):
        """
        Fills an Amazon DynamoDB table with the specified data, using the Boto3
        Table.batch_writer() function to put the items in the table.
        Inside the context manager, Table.batch_writer builds a list of
        requests. On exiting the context manager, Table.batch_writer starts sending
        batches of write requests to Amazon DynamoDB and automatically
        handles chunking, buffering, and retrying.

        :param movies: The data to put in the table. Each item must contain at least
                       the keys required by the schema that was specified when the
                       table was created.
        """
        try:
            with self.table.batch_writer() as writer:
                for movie in movies:
                    writer.put_item(Item=movie)
        except ClientError as err:
            logger.error(
                "Couldn't load data into table %s. Here's why: %s: %s",
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

创建用于存储电影数据的表。

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def create_table(self, table_name):
        """
        Creates an Amazon DynamoDB table that can be used to store movie data.
        The table uses the release year of the movie as the partition key and the
        title as the sort key.

        :param table_name: The name of the table to create.
        :return: The newly created table.
        """
        try:
            self.table = self.dyn_resource.create_table(
                TableName=table_name,
                KeySchema=[
                    {"AttributeName": "year", "KeyType": "HASH"},  # Partition key
                    {"AttributeName": "title", "KeyType": "RANGE"},  # Sort key
                ],
                AttributeDefinitions=[
                    {"AttributeName": "year", "AttributeType": "N"},
                    {"AttributeName": "title", "AttributeType": "S"},
                ],
                ProvisionedThroughput={
                    "ReadCapacityUnits": 10,
                    "WriteCapacityUnits": 10,
                },
            )
            self.table.wait_until_exists()
        except ClientError as err:
            logger.error(
                "Couldn't create table %s. Here's why: %s: %s",
                table_name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return self.table

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def delete_movie(self, title, year):
        """
        Deletes a movie from the table.

        :param title: The title of the movie to delete.
        :param year: The release year of the movie to delete.
        """
        try:
            self.table.delete_item(Key={"year": year, "title": title})
        except ClientError as err:
            logger.error(
                "Couldn't delete movie %s. Here's why: %s: %s",
                title,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

您可以指定条件，以便只有在项目满足特定条件时才会被删除。

class UpdateQueryWrapper:
    def __init__(self, table):
        self.table = table


    def delete_underrated_movie(self, title, year, rating):
        """
        Deletes a movie only if it is rated below a specified value. By using a
        condition expression in a delete operation, you can specify that an item is
        deleted only when it meets certain criteria.

        :param title: The title of the movie to delete.
        :param year: The release year of the movie to delete.
        :param rating: The rating threshold to check before deleting the movie.
        """
        try:
            self.table.delete_item(
                Key={"year": year, "title": title},
                ConditionExpression="info.rating <= :val",
                ExpressionAttributeValues={":val": Decimal(str(rating))},
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ConditionalCheckFailedException":
                logger.warning(
                    "Didn't delete %s because its rating is greater than %s.",
                    title,
                    rating,
                )
            else:
                logger.error(
                    "Couldn't delete movie %s. Here's why: %s: %s",
                    title,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            raise

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def delete_table(self):
        """
        Deletes the table.
        """
        try:
            self.table.delete()
            self.table = None
        except ClientError as err:
            logger.error(
                "Couldn't delete table. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def exists(self, table_name):
        """
        Determines whether a table exists. As a side effect, stores the table in
        a member variable.

        :param table_name: The name of the table to check.
        :return: True when the table exists; otherwise, False.
        """
        try:
            table = self.dyn_resource.Table(table_name)
            table.load()
            exists = True
        except ClientError as err:
            if err.response["Error"]["Code"] == "ResourceNotFoundException":
                exists = False
            else:
                logger.error(
                    "Couldn't check for existence of %s. Here's why: %s: %s",
                    table_name,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
                raise
        else:
            self.table = table
        return exists

import boto3

def describe_ttl(table_name, region):
    """
    Describes TTL on an existing table, as well as a region.

    :param table_name: String representing the name of the table
    :param region: AWS Region of the table - example `us-east-1`
    :return: Time to live description.
    """
    try:
        dynamodb = boto3.resource('dynamodb', region_name=region)
        ttl_description = dynamodb.describe_time_to_live(TableName=table_name)
        print(
            f"TimeToLive for table {table_name} is status {ttl_description['TimeToLiveDescription']['TimeToLiveStatus']}")

        return ttl_description
    except Exception as e:
        print(f"Error describing table: {e}")
        raise


# Enter your own table name and AWS region
describe_ttl('your-table-name', 'us-east-1')

class PartiQLWrapper:
    """
    Encapsulates a DynamoDB resource to run PartiQL statements.
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource


    def run_partiql(self, statement, params):
        """
        Runs a PartiQL statement. A Boto3 resource is used even though
        `execute_statement` is called on the underlying `client` object because the
        resource transforms input and output from plain old Python objects (POPOs) to
        the DynamoDB format. If you create the client directly, you must do these
        transforms yourself.

        :param statement: The PartiQL statement.
        :param params: The list of PartiQL parameters. These are applied to the
                       statement in the order they are listed.
        :return: The items returned from the statement, if any.
        """
        try:
            output = self.dyn_resource.meta.client.execute_statement(
                Statement=statement, Parameters=params
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ResourceNotFoundException":
                logger.error(
                    "Couldn't execute PartiQL '%s' because the table does not exist.",
                    statement,
                )
            else:
                logger.error(
                    "Couldn't execute PartiQL '%s'. Here's why: %s: %s",
                    statement,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            raise
        else:
            return output

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def get_movie(self, title, year):
        """
        Gets movie data from the table for a specific movie.

        :param title: The title of the movie.
        :param year: The release year of the movie.
        :return: The data about the requested movie.
        """
        try:
            response = self.table.get_item(Key={"year": year, "title": title})
        except ClientError as err:
            logger.error(
                "Couldn't get movie %s from table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Item"]

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def list_tables(self):
        """
        Lists the Amazon DynamoDB tables for the current account.

        :return: The list of tables.
        """
        try:
            tables = []
            for table in self.dyn_resource.tables.all():
                print(table.name)
                tables.append(table)
        except ClientError as err:
            logger.error(
                "Couldn't list tables. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return tables

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def add_movie(self, title, year, plot, rating):
        """
        Adds a movie to the table.

        :param title: The title of the movie.
        :param year: The release year of the movie.
        :param plot: The plot summary of the movie.
        :param rating: The quality rating of the movie.
        """
        try:
            self.table.put_item(
                Item={
                    "year": year,
                    "title": title,
                    "info": {"plot": plot, "rating": Decimal(str(rating))},
                }
            )
        except ClientError as err:
            logger.error(
                "Couldn't add movie %s to table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

使用关键条件表达式查询项目。

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def query_movies(self, year):
        """
        Queries for movies that were released in the specified year.

        :param year: The year to query.
        :return: The list of movies that were released in the specified year.
        """
        try:
            response = self.table.query(KeyConditionExpression=Key("year").eq(year))
        except ClientError as err:
            logger.error(
                "Couldn't query for movies released in %s. Here's why: %s: %s",
                year,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Items"]

查询项目并将其投影以返回数据的子集。

class UpdateQueryWrapper:
    def __init__(self, table):
        self.table = table


    def query_and_project_movies(self, year, title_bounds):
        """
        Query for movies that were released in a specified year and that have titles
        that start within a range of letters. A projection expression is used
        to return a subset of data for each movie.

        :param year: The release year to query.
        :param title_bounds: The range of starting letters to query.
        :return: The list of movies.
        """
        try:
            response = self.table.query(
                ProjectionExpression="#yr, title, info.genres, info.actors[0]",
                ExpressionAttributeNames={"#yr": "year"},
                KeyConditionExpression=(
                    Key("year").eq(year)
                    & Key("title").between(
                        title_bounds["first"], title_bounds["second"]
                    )
                ),
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ValidationException":
                logger.warning(
                    "There's a validation error. Here's the message: %s: %s",
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            else:
                logger.error(
                    "Couldn't query for movies. Here's why: %s: %s",
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
                raise
        else:
            return response["Items"]

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def scan_movies(self, year_range):
        """
        Scans for movies that were released in a range of years.
        Uses a projection expression to return a subset of data for each movie.

        :param year_range: The range of years to retrieve.
        :return: The list of movies released in the specified years.
        """
        movies = []
        scan_kwargs = {
            "FilterExpression": Key("year").between(
                year_range["first"], year_range["second"]
            ),
            "ProjectionExpression": "#yr, title, info.rating",
            "ExpressionAttributeNames": {"#yr": "year"},
        }
        try:
            done = False
            start_key = None
            while not done:
                if start_key:
                    scan_kwargs["ExclusiveStartKey"] = start_key
                response = self.table.scan(**scan_kwargs)
                movies.extend(response.get("Items", []))
                start_key = response.get("LastEvaluatedKey", None)
                done = start_key is None
        except ClientError as err:
            logger.error(
                "Couldn't scan for movies. Here's why: %s: %s",
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise

        return movies

使用更新表达式更新项目

class Movies:
    """Encapsulates an Amazon DynamoDB table of movie data.

    Example data structure for a movie record in this table:
        {
            "year": 1999,
            "title": "For Love of the Game",
            "info": {
                "directors": ["Sam Raimi"],
                "release_date": "1999-09-15T00:00:00Z",
                "rating": 6.3,
                "plot": "A washed up pitcher flashes through his career.",
                "rank": 4987,
                "running_time_secs": 8220,
                "actors": [
                    "Kevin Costner",
                    "Kelly Preston",
                    "John C. Reilly"
                ]
            }
        }
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource
        # The table variable is set during the scenario in the call to
        # 'exists' if the table exists. Otherwise, it is set by 'create_table'.
        self.table = None


    def update_movie(self, title, year, rating, plot):
        """
        Updates rating and plot data for a movie in the table.

        :param title: The title of the movie to update.
        :param year: The release year of the movie to update.
        :param rating: The updated rating to the give the movie.
        :param plot: The updated plot summary to give the movie.
        :return: The fields that were updated, with their new values.
        """
        try:
            response = self.table.update_item(
                Key={"year": year, "title": title},
                UpdateExpression="set info.rating=:r, info.plot=:p",
                ExpressionAttributeValues={":r": Decimal(str(rating)), ":p": plot},
                ReturnValues="UPDATED_NEW",
            )
        except ClientError as err:
            logger.error(
                "Couldn't update movie %s in table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Attributes"]

使用包含算术运算的更新表达式更新项目。

class UpdateQueryWrapper:
    def __init__(self, table):
        self.table = table


    def update_rating(self, title, year, rating_change):
        """
        Updates the quality rating of a movie in the table by using an arithmetic
        operation in the update expression. By specifying an arithmetic operation,
        you can adjust a value in a single request, rather than first getting its
        value and then setting its new value.

        :param title: The title of the movie to update.
        :param year: The release year of the movie to update.
        :param rating_change: The amount to add to the current rating for the movie.
        :return: The updated rating.
        """
        try:
            response = self.table.update_item(
                Key={"year": year, "title": title},
                UpdateExpression="set info.rating = info.rating + :val",
                ExpressionAttributeValues={":val": Decimal(str(rating_change))},
                ReturnValues="UPDATED_NEW",
            )
        except ClientError as err:
            logger.error(
                "Couldn't update movie %s in table %s. Here's why: %s: %s",
                title,
                self.table.name,
                err.response["Error"]["Code"],
                err.response["Error"]["Message"],
            )
            raise
        else:
            return response["Attributes"]

只有在项目满足特定条件时才更新项目。

class UpdateQueryWrapper:
    def __init__(self, table):
        self.table = table


    def remove_actors(self, title, year, actor_threshold):
        """
        Removes an actor from a movie, but only when the number of actors is greater
        than a specified threshold. If the movie does not list more than the threshold,
        no actors are removed.

        :param title: The title of the movie to update.
        :param year: The release year of the movie to update.
        :param actor_threshold: The threshold of actors to check.
        :return: The movie data after the update.
        """
        try:
            response = self.table.update_item(
                Key={"year": year, "title": title},
                UpdateExpression="remove info.actors[0]",
                ConditionExpression="size(info.actors) > :num",
                ExpressionAttributeValues={":num": actor_threshold},
                ReturnValues="ALL_NEW",
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ConditionalCheckFailedException":
                logger.warning(
                    "Didn't update %s because it has fewer than %s actors.",
                    title,
                    actor_threshold + 1,
                )
            else:
                logger.error(
                    "Couldn't update movie %s. Here's why: %s: %s",
                    title,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            raise
        else:
            return response["Attributes"]

在现有 DynamoDB 表TTL上启用。

import boto3

def enable_ttl(table_name, ttl_attribute_name):
    """
    Enables TTL on DynamoDB table for a given attribute name
        on success, returns a status code of 200
        on error, throws an exception

    :param table_name: Name of the DynamoDB table
    :param ttl_attribute_name: The name of the TTL attribute being provided to the table.
    """
    try:
        dynamodb = boto3.client('dynamodb')

        # Enable TTL on an existing DynamoDB table
        response = dynamodb.update_time_to_live(
            TableName=table_name,
            TimeToLiveSpecification={
                'Enabled': True,
                'AttributeName': ttl_attribute_name
            }
        )

        # In the returned response, check for a successful status code.
        if response['ResponseMetadata']['HTTPStatusCode'] == 200:
            print("TTL has been enabled successfully.")
        else:
            print(f"Failed to enable TTL, status code {response['ResponseMetadata']['HTTPStatusCode']}")
        return response
    except Exception as ex:
        print("Couldn't enable TTL in table %s. Here's why: %s" % (table_name, ex))
        raise


# your values
enable_ttl('your-table-name', 'expireAt')

在现有 DynamoDB 表TTL上禁用。

import boto3

def disable_ttl(table_name, ttl_attribute_name):
    """
    Disables TTL on DynamoDB table for a given attribute name
        on success, returns a status code of 200
        on error, throws an exception

    :param table_name: Name of the DynamoDB table being modified
    :param ttl_attribute_name: The name of the TTL attribute being provided to the table.
    """
    try:
        dynamodb = boto3.client('dynamodb')

        # Enable TTL on an existing DynamoDB table
        response = dynamodb.update_time_to_live(
            TableName=table_name,
            TimeToLiveSpecification={
                'Enabled': False,
                'AttributeName': ttl_attribute_name
            }
        )

        # In the returned response, check for a successful status code.
        if response['ResponseMetadata']['HTTPStatusCode'] == 200:
            print("TTL has been disabled successfully.")
        else:
            print(f"Failed to disable TTL, status code {response['ResponseMetadata']['HTTPStatusCode']}")
    except Exception as ex:
        print("Couldn't disable TTL in table %s. Here's why: %s" % (table_name, ex))
        raise


# your values
disable_ttl('your-table-name', 'expireAt')

使用DAX或 Boto3 客户端创建表。

import boto3


def create_dax_table(dyn_resource=None):
    """
    Creates a DynamoDB table.

    :param dyn_resource: Either a Boto3 or DAX resource.
    :return: The newly created table.
    """
    if dyn_resource is None:
        dyn_resource = boto3.resource("dynamodb")

    table_name = "TryDaxTable"
    params = {
        "TableName": table_name,
        "KeySchema": [
            {"AttributeName": "partition_key", "KeyType": "HASH"},
            {"AttributeName": "sort_key", "KeyType": "RANGE"},
        ],
        "AttributeDefinitions": [
            {"AttributeName": "partition_key", "AttributeType": "N"},
            {"AttributeName": "sort_key", "AttributeType": "N"},
        ],
        "ProvisionedThroughput": {"ReadCapacityUnits": 10, "WriteCapacityUnits": 10},
    }
    table = dyn_resource.create_table(**params)
    print(f"Creating {table_name}...")
    table.wait_until_exists()
    return table


if __name__ == "__main__":
    dax_table = create_dax_table()
    print(f"Created table.")

将测试数据写入表中。

import boto3


def write_data_to_dax_table(key_count, item_size, dyn_resource=None):
    """
    Writes test data to the demonstration table.

    :param key_count: The number of partition and sort keys to use to populate the
                      table. The total number of items is key_count * key_count.
    :param item_size: The size of non-key data for each test item.
    :param dyn_resource: Either a Boto3 or DAX resource.
    """
    if dyn_resource is None:
        dyn_resource = boto3.resource("dynamodb")

    table = dyn_resource.Table("TryDaxTable")
    some_data = "X" * item_size

    for partition_key in range(1, key_count + 1):
        for sort_key in range(1, key_count + 1):
            table.put_item(
                Item={
                    "partition_key": partition_key,
                    "sort_key": sort_key,
                    "some_data": some_data,
                }
            )
            print(f"Put item ({partition_key}, {sort_key}) succeeded.")


if __name__ == "__main__":
    write_key_count = 10
    write_item_size = 1000
    print(
        f"Writing {write_key_count*write_key_count} items to the table. "
        f"Each item is {write_item_size} characters."
    )
    write_data_to_dax_table(write_key_count, write_item_size)

获取客户端和 Boto3 DAX 客户端多次迭代的项目，并报告每次迭代所花费的时间。

import argparse
import sys
import time
import amazondax
import boto3


def get_item_test(key_count, iterations, dyn_resource=None):
    """
    Gets items from the table a specified number of times. The time before the
    first iteration and the time after the last iteration are both captured
    and reported.

    :param key_count: The number of items to get from the table in each iteration.
    :param iterations: The number of iterations to run.
    :param dyn_resource: Either a Boto3 or DAX resource.
    :return: The start and end times of the test.
    """
    if dyn_resource is None:
        dyn_resource = boto3.resource("dynamodb")

    table = dyn_resource.Table("TryDaxTable")
    start = time.perf_counter()
    for _ in range(iterations):
        for partition_key in range(1, key_count + 1):
            for sort_key in range(1, key_count + 1):
                table.get_item(
                    Key={"partition_key": partition_key, "sort_key": sort_key}
                )
                print(".", end="")
                sys.stdout.flush()
    print()
    end = time.perf_counter()
    return start, end


if __name__ == "__main__":
    # pylint: disable=not-context-manager
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "endpoint_url",
        nargs="?",
        help="When specified, the DAX cluster endpoint. Otherwise, DAX is not used.",
    )
    args = parser.parse_args()

    test_key_count = 10
    test_iterations = 50
    if args.endpoint_url:
        print(
            f"Getting each item from the table {test_iterations} times, "
            f"using the DAX client."
        )
        # Use a with statement so the DAX client closes the cluster after completion.
        with amazondax.AmazonDaxClient.resource(endpoint_url=args.endpoint_url) as dax:
            test_start, test_end = get_item_test(
                test_key_count, test_iterations, dyn_resource=dax
            )
    else:
        print(
            f"Getting each item from the table {test_iterations} times, "
            f"using the Boto3 client."
        )
        test_start, test_end = get_item_test(test_key_count, test_iterations)
    print(
        f"Total time: {test_end - test_start:.4f} sec. Average time: "
        f"{(test_end - test_start)/ test_iterations}."
    )

在表格中查询客户端和 Boto3 DAX 客户端的迭代次数，并报告每次迭代所花费的时间。

import argparse
import time
import sys
import amazondax
import boto3
from boto3.dynamodb.conditions import Key


def query_test(partition_key, sort_keys, iterations, dyn_resource=None):
    """
    Queries the table a specified number of times. The time before the
    first iteration and the time after the last iteration are both captured
    and reported.

    :param partition_key: The partition key value to use in the query. The query
                          returns items that have partition keys equal to this value.
    :param sort_keys: The range of sort key values for the query. The query returns
                      items that have sort key values between these two values.
    :param iterations: The number of iterations to run.
    :param dyn_resource: Either a Boto3 or DAX resource.
    :return: The start and end times of the test.
    """
    if dyn_resource is None:
        dyn_resource = boto3.resource("dynamodb")

    table = dyn_resource.Table("TryDaxTable")
    key_condition_expression = Key("partition_key").eq(partition_key) & Key(
        "sort_key"
    ).between(*sort_keys)

    start = time.perf_counter()
    for _ in range(iterations):
        table.query(KeyConditionExpression=key_condition_expression)
        print(".", end="")
        sys.stdout.flush()
    print()
    end = time.perf_counter()
    return start, end


if __name__ == "__main__":
    # pylint: disable=not-context-manager
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "endpoint_url",
        nargs="?",
        help="When specified, the DAX cluster endpoint. Otherwise, DAX is not used.",
    )
    args = parser.parse_args()

    test_partition_key = 5
    test_sort_keys = (2, 9)
    test_iterations = 100
    if args.endpoint_url:
        print(f"Querying the table {test_iterations} times, using the DAX client.")
        # Use a with statement so the DAX client closes the cluster after completion.
        with amazondax.AmazonDaxClient.resource(endpoint_url=args.endpoint_url) as dax:
            test_start, test_end = query_test(
                test_partition_key, test_sort_keys, test_iterations, dyn_resource=dax
            )
    else:
        print(f"Querying the table {test_iterations} times, using the Boto3 client.")
        test_start, test_end = query_test(
            test_partition_key, test_sort_keys, test_iterations
        )

    print(
        f"Total time: {test_end - test_start:.4f} sec. Average time: "
        f"{(test_end - test_start)/test_iterations}."
    )

在表格中扫描客户端和 Boto3 DAX 客户端的多次迭代，并报告每个迭代所花费的时间。

import argparse
import time
import sys
import amazondax
import boto3


def scan_test(iterations, dyn_resource=None):
    """
    Scans the table a specified number of times. The time before the
    first iteration and the time after the last iteration are both captured
    and reported.

    :param iterations: The number of iterations to run.
    :param dyn_resource: Either a Boto3 or DAX resource.
    :return: The start and end times of the test.
    """
    if dyn_resource is None:
        dyn_resource = boto3.resource("dynamodb")

    table = dyn_resource.Table("TryDaxTable")
    start = time.perf_counter()
    for _ in range(iterations):
        table.scan()
        print(".", end="")
        sys.stdout.flush()
    print()
    end = time.perf_counter()
    return start, end


if __name__ == "__main__":
    # pylint: disable=not-context-manager
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "endpoint_url",
        nargs="?",
        help="When specified, the DAX cluster endpoint. Otherwise, DAX is not used.",
    )
    args = parser.parse_args()

    test_iterations = 100
    if args.endpoint_url:
        print(f"Scanning the table {test_iterations} times, using the DAX client.")
        # Use a with statement so the DAX client closes the cluster after completion.
        with amazondax.AmazonDaxClient.resource(endpoint_url=args.endpoint_url) as dax:
            test_start, test_end = scan_test(test_iterations, dyn_resource=dax)
    else:
        print(f"Scanning the table {test_iterations} times, using the Boto3 client.")
        test_start, test_end = scan_test(test_iterations)
    print(
        f"Total time: {test_end - test_start:.4f} sec. Average time: "
        f"{(test_end - test_start)/test_iterations}."
    )

删除表。

import boto3


def delete_dax_table(dyn_resource=None):
    """
    Deletes the demonstration table.

    :param dyn_resource: Either a Boto3 or DAX resource.
    """
    if dyn_resource is None:
        dyn_resource = boto3.resource("dynamodb")

    table = dyn_resource.Table("TryDaxTable")
    table.delete()

    print(f"Deleting {table.name}...")
    table.wait_until_not_exists()


if __name__ == "__main__":
    delete_dax_table()
    print("Table deleted!")

import boto3
from datetime import datetime, timedelta
from botocore.exceptions import ClientError

def update_dynamodb_item(table_name, region, primary_key, sort_key, ttl_attribute):
    """
    Updates an existing record in a DynamoDB table with a new or updated TTL attribute.

    :param table_name: Name of the DynamoDB table
    :param region: AWS Region of the table - example `us-east-1`
    :param primary_key: one attribute known as the partition key.
    :param sort_key: Also known as a range attribute.
    :param ttl_attribute: name of the TTL attribute in the target DynamoDB table
    :return:
    """
    try:
        dynamodb = boto3.resource('dynamodb', region_name=region)
        table = dynamodb.Table(table_name)

        # Generate updated TTL in epoch second format
        updated_expiration_time = int((datetime.now() + timedelta(days=90)).timestamp())

        # Define the update expression for adding/updating a new attribute
        update_expression = "SET newAttribute = :val1"

        # Define the condition expression for checking if 'expireAt' is not expired
        condition_expression = "expireAt > :val2"

        # Define the expression attribute values
        expression_attribute_values = {
            ':val1': ttl_attribute,
            ':val2': updated_expiration_time
        }

        response = table.update_item(
            Key={
                'primaryKey': primary_key,
                'sortKey': sort_key
            },
            UpdateExpression=update_expression,
            ConditionExpression=condition_expression,
            ExpressionAttributeValues=expression_attribute_values
        )

        print("Item updated successfully.")
        return response['ResponseMetadata']['HTTPStatusCode']  # Ideally a 200 OK
    except ClientError as e:
        if e.response['Error']['Code'] == "ConditionalCheckFailedException":
            print("Condition check failed: Item's 'expireAt' is expired.")
        else:
            print(f"Error updating item: {e}")
    except Exception as e:
        print(f"Error updating item: {e}")

# replace with your values
update_dynamodb_item('your-table-name', 'us-east-1', 'your-partition-key-value', 'your-sort-key-value',
                     'your-ttl-attribute-value')

演示如何使用 AWS Chalice 和创建RESTAPI使用 Amazon Gate API way 和 Amazon DynamoDB AWS Lambda的无服务器。 AWS SDK for Python (Boto3) RESTAPI它模拟了一个使用虚构数据追踪美国每天 COVID 19例病例的系统。了解如何：

有关如何设置和运行的完整源代码和说明，请参阅上的完整示例GitHub。

演示如何使用 with 创建信使应用程序，该 AWS SDK for Python (Boto3) 应用程序从 Amazon DynamoDB 表中检索消息记录并通过亚马逊简单队列服务 (Amazon) 将其发送。 AWS Step Functions SQS状态机集成了扫描数据库中是否有未发送消息的 AWS Lambda 功能。

有关如何设置和运行的完整源代码和说明，请参阅上的完整示例GitHub。

演示如何使用创建一项REST服务，通过亚马逊简单电子邮件服务 (Amazon) 来跟踪亚马逊 DynamoDB 中的工作项目并通过电子邮件发送报告。 AWS SDK for Python (Boto3) SES此示例使用 Flask Web 框架来处理HTTP路由，并与 React 网页集成以呈现功能齐全的 Web 应用程序。

有关完整的源代码以及如何设置和运行的说明，请参阅上的 “AWS 代码示例存储库” 中的完整示例 GitHub。

演示如何使用 with Amazon API Gateway V2 来创建 AWS SDK for Python (Boto3) 与亚马逊 DynamoDB 集成API的 websocket。 AWS Lambda

有关如何设置和运行的完整源代码和说明，请参阅上的完整示例GitHub。

import boto3
from datetime import datetime, timedelta

def create_dynamodb_item(table_name, region, primary_key, sort_key):
    """
    Creates a DynamoDB item with an attached expiry attribute.

    :param table_name: Table name for the boto3 resource to target when creating an item
    :param region: string representing the AWS region. Example: `us-east-1`
    :param primary_key: one attribute known as the partition key.
    :param sort_key: Also known as a range attribute.
    :return: Void (nothing)
    """
    try:
        dynamodb = boto3.resource('dynamodb', region_name=region)
        table = dynamodb.Table(table_name)

        # Get the current time in epoch second format
        current_time = int(datetime.now().timestamp())

        # Calculate the expiration time (90 days from now) in epoch second format
        expiration_time = int((datetime.now() + timedelta(days=90)).timestamp())

        item = {
            'primaryKey': primary_key,
            'sortKey': sort_key,
            'creationDate': current_time,
            'expireAt': expiration_time
        }

        table.put_item(Item=item)

        print("Item created successfully.")
    except Exception as e:
        print(f"Error creating item: {e}")
        raise


# Use your own values
create_dynamodb_item('your-table-name', 'us-west-2', 'your-partition-key-value', 'your-sort-key-value')

创建一个可以运行批量 PartiQL 语句的类。

from datetime import datetime
from decimal import Decimal
import logging
from pprint import pprint

import boto3
from botocore.exceptions import ClientError

from scaffold import Scaffold

logger = logging.getLogger(__name__)

class PartiQLBatchWrapper:
    """
    Encapsulates a DynamoDB resource to run PartiQL statements.
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource


    def run_partiql(self, statements, param_list):
        """
        Runs a PartiQL statement. A Boto3 resource is used even though
        `execute_statement` is called on the underlying `client` object because the
        resource transforms input and output from plain old Python objects (POPOs) to
        the DynamoDB format. If you create the client directly, you must do these
        transforms yourself.

        :param statements: The batch of PartiQL statements.
        :param param_list: The batch of PartiQL parameters that are associated with
                           each statement. This list must be in the same order as the
                           statements.
        :return: The responses returned from running the statements, if any.
        """
        try:
            output = self.dyn_resource.meta.client.batch_execute_statement(
                Statements=[
                    {"Statement": statement, "Parameters": params}
                    for statement, params in zip(statements, param_list)
                ]
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ResourceNotFoundException":
                logger.error(
                    "Couldn't execute batch of PartiQL statements because the table "
                    "does not exist."
                )
            else:
                logger.error(
                    "Couldn't execute batch of PartiQL statements. Here's why: %s: %s",
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            raise
        else:
            return output

运行创建表并批量运行 PartIQL 查询的场景。

def run_scenario(scaffold, wrapper, table_name):
    logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")

    print("-" * 88)
    print("Welcome to the Amazon DynamoDB PartiQL batch statement demo.")
    print("-" * 88)

    print(f"Creating table '{table_name}' for the demo...")
    scaffold.create_table(table_name)
    print("-" * 88)

    movie_data = [
        {
            "title": f"House PartiQL",
            "year": datetime.now().year - 5,
            "info": {
                "plot": "Wacky high jinks result from querying a mysterious database.",
                "rating": Decimal("8.5"),
            },
        },
        {
            "title": f"House PartiQL 2",
            "year": datetime.now().year - 3,
            "info": {
                "plot": "Moderate high jinks result from querying another mysterious database.",
                "rating": Decimal("6.5"),
            },
        },
        {
            "title": f"House PartiQL 3",
            "year": datetime.now().year - 1,
            "info": {
                "plot": "Tepid high jinks result from querying yet another mysterious database.",
                "rating": Decimal("2.5"),
            },
        },
    ]

    print(f"Inserting a batch of movies into table '{table_name}.")
    statements = [
        f'INSERT INTO "{table_name}" ' f"VALUE {{'title': ?, 'year': ?, 'info': ?}}"
    ] * len(movie_data)
    params = [list(movie.values()) for movie in movie_data]
    wrapper.run_partiql(statements, params)
    print("Success!")
    print("-" * 88)

    print(f"Getting data for a batch of movies.")
    statements = [f'SELECT * FROM "{table_name}" WHERE title=? AND year=?'] * len(
        movie_data
    )
    params = [[movie["title"], movie["year"]] for movie in movie_data]
    output = wrapper.run_partiql(statements, params)
    for item in output["Responses"]:
        print(f"\n{item['Item']['title']}, {item['Item']['year']}")
        pprint(item["Item"])
    print("-" * 88)

    ratings = [Decimal("7.7"), Decimal("5.5"), Decimal("1.3")]
    print(f"Updating a batch of movies with new ratings.")
    statements = [
        f'UPDATE "{table_name}" SET info.rating=? ' f"WHERE title=? AND year=?"
    ] * len(movie_data)
    params = [
        [rating, movie["title"], movie["year"]]
        for rating, movie in zip(ratings, movie_data)
    ]
    wrapper.run_partiql(statements, params)
    print("Success!")
    print("-" * 88)

    print(f"Getting projected data from the table to verify our update.")
    output = wrapper.dyn_resource.meta.client.execute_statement(
        Statement=f'SELECT title, info.rating FROM "{table_name}"'
    )
    pprint(output["Items"])
    print("-" * 88)

    print(f"Deleting a batch of movies from the table.")
    statements = [f'DELETE FROM "{table_name}" WHERE title=? AND year=?'] * len(
        movie_data
    )
    params = [[movie["title"], movie["year"]] for movie in movie_data]
    wrapper.run_partiql(statements, params)
    print("Success!")
    print("-" * 88)

    print(f"Deleting table '{table_name}'...")
    scaffold.delete_table()
    print("-" * 88)

    print("\nThanks for watching!")
    print("-" * 88)


if __name__ == "__main__":
    try:
        dyn_res = boto3.resource("dynamodb")
        scaffold = Scaffold(dyn_res)
        movies = PartiQLBatchWrapper(dyn_res)
        run_scenario(scaffold, movies, "doc-example-table-partiql-movies")
    except Exception as e:
        print(f"Something went wrong with the demo! Here's what: {e}")

创建一个可以运行 PartiQL 语句的类。

from datetime import datetime
from decimal import Decimal
import logging
from pprint import pprint

import boto3
from botocore.exceptions import ClientError

from scaffold import Scaffold

logger = logging.getLogger(__name__)

class PartiQLWrapper:
    """
    Encapsulates a DynamoDB resource to run PartiQL statements.
    """

    def __init__(self, dyn_resource):
        """
        :param dyn_resource: A Boto3 DynamoDB resource.
        """
        self.dyn_resource = dyn_resource


    def run_partiql(self, statement, params):
        """
        Runs a PartiQL statement. A Boto3 resource is used even though
        `execute_statement` is called on the underlying `client` object because the
        resource transforms input and output from plain old Python objects (POPOs) to
        the DynamoDB format. If you create the client directly, you must do these
        transforms yourself.

        :param statement: The PartiQL statement.
        :param params: The list of PartiQL parameters. These are applied to the
                       statement in the order they are listed.
        :return: The items returned from the statement, if any.
        """
        try:
            output = self.dyn_resource.meta.client.execute_statement(
                Statement=statement, Parameters=params
            )
        except ClientError as err:
            if err.response["Error"]["Code"] == "ResourceNotFoundException":
                logger.error(
                    "Couldn't execute PartiQL '%s' because the table does not exist.",
                    statement,
                )
            else:
                logger.error(
                    "Couldn't execute PartiQL '%s'. Here's why: %s: %s",
                    statement,
                    err.response["Error"]["Code"],
                    err.response["Error"]["Message"],
                )
            raise
        else:
            return output

运行创建表并运行 PartiQL 查询的场景。

def run_scenario(scaffold, wrapper, table_name):
    logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s")

    print("-" * 88)
    print("Welcome to the Amazon DynamoDB PartiQL single statement demo.")
    print("-" * 88)

    print(f"Creating table '{table_name}' for the demo...")
    scaffold.create_table(table_name)
    print("-" * 88)

    title = "24 Hour PartiQL People"
    year = datetime.now().year
    plot = "A group of data developers discover a new query language they can't stop using."
    rating = Decimal("9.9")

    print(f"Inserting movie '{title}' released in {year}.")
    wrapper.run_partiql(
        f"INSERT INTO \"{table_name}\" VALUE {{'title': ?, 'year': ?, 'info': ?}}",
        [title, year, {"plot": plot, "rating": rating}],
    )
    print("Success!")
    print("-" * 88)

    print(f"Getting data for movie '{title}' released in {year}.")
    output = wrapper.run_partiql(
        f'SELECT * FROM "{table_name}" WHERE title=? AND year=?', [title, year]
    )
    for item in output["Items"]:
        print(f"\n{item['title']}, {item['year']}")
        pprint(output["Items"])
    print("-" * 88)

    rating = Decimal("2.4")
    print(f"Updating movie '{title}' with a rating of {float(rating)}.")
    wrapper.run_partiql(
        f'UPDATE "{table_name}" SET info.rating=? WHERE title=? AND year=?',
        [rating, title, year],
    )
    print("Success!")
    print("-" * 88)

    print(f"Getting data again to verify our update.")
    output = wrapper.run_partiql(
        f'SELECT * FROM "{table_name}" WHERE title=? AND year=?', [title, year]
    )
    for item in output["Items"]:
        print(f"\n{item['title']}, {item['year']}")
        pprint(output["Items"])
    print("-" * 88)

    print(f"Deleting movie '{title}' released in {year}.")
    wrapper.run_partiql(
        f'DELETE FROM "{table_name}" WHERE title=? AND year=?', [title, year]
    )
    print("Success!")
    print("-" * 88)

    print(f"Deleting table '{table_name}'...")
    scaffold.delete_table()
    print("-" * 88)

    print("\nThanks for watching!")
    print("-" * 88)


if __name__ == "__main__":
    try:
        dyn_res = boto3.resource("dynamodb")
        scaffold = Scaffold(dyn_res)
        movies = PartiQLWrapper(dyn_res)
        run_scenario(scaffold, movies, "doc-example-table-partiql-movies")
    except Exception as e:
        print(f"Something went wrong with the demo! Here's what: {e}")

import boto3
from datetime import datetime

def query_dynamodb_items(table_name, partition_key):
    """

    :param table_name: Name of the DynamoDB table
    :param partition_key:
    :return:
    """
    try:
        # Initialize a DynamoDB resource
        dynamodb = boto3.resource('dynamodb',
                                  region_name='us-east-1')

        # Specify your table
        table = dynamodb.Table(table_name)

        # Get the current time in epoch format
        current_time = int(datetime.now().timestamp())

        # Perform the query operation with a filter expression to exclude expired items
        # response = table.query(
        #    KeyConditionExpression=boto3.dynamodb.conditions.Key('partitionKey').eq(partition_key),
        #    FilterExpression=boto3.dynamodb.conditions.Attr('expireAt').gt(current_time)
        # )
        response = table.query(
            KeyConditionExpression=dynamodb.conditions.Key('partitionKey').eq(partition_key),
            FilterExpression=dynamodb.conditions.Attr('expireAt').gt(current_time)
        )

        # Print the items that are not expired
        for item in response['Items']:
            print(item)

    except Exception as e:
        print(f"Error querying items: {e}")


# Call the function with your values
query_dynamodb_items('Music', 'your-partition-key-value')

import boto3
from datetime import datetime, timedelta

def update_dynamodb_item(table_name, region, primary_key, sort_key):
    """
    Update an existing DynamoDB item with a TTL.
    :param table_name: Name of the DynamoDB table
    :param region: AWS Region of the table - example `us-east-1`
    :param primary_key: one attribute known as the partition key.
    :param sort_key: Also known as a range attribute.
    :return: Void (nothing)
    """
    try:
        # Create the DynamoDB resource.
        dynamodb = boto3.resource('dynamodb', region_name=region)
        table = dynamodb.Table(table_name)

        # Get the current time in epoch second format
        current_time = int(datetime.now().timestamp())

        # Calculate the expireAt time (90 days from now) in epoch second format
        expire_at = int((datetime.now() + timedelta(days=90)).timestamp())

        table.update_item(
            Key={
                'partitionKey': primary_key,
                'sortKey': sort_key
            },
            UpdateExpression="set updatedAt=:c, expireAt=:e",
            ExpressionAttributeValues={
                ':c': current_time,
                ':e': expire_at
            },
        )

        print("Item updated successfully.")
    except Exception as e:
        print(f"Error updating item: {e}")


# Replace with your own values
update_dynamodb_item('your-table-name', 'us-west-2', 'your-partition-key-value', 'your-sort-key-value')

通过 Python 将 DynamoDB 事件与 Lambda 结合使用。

import json

def lambda_handler(event, context):
    print(json.dumps(event, indent=2))

    for record in event['Records']:
        log_dynamodb_record(record)

def log_dynamodb_record(record):
    print(record['eventID'])
    print(record['eventName'])
    print(f"DynamoDB Record: {json.dumps(record['dynamodb'])}")

报告使用 Python 通过 Lambda 进行 DynamoDB 批处理项目失败。

# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0
def handler(event, context):
    records = event.get("Records")
    curRecordSequenceNumber = ""
    
    for record in records:
        try:
            # Process your record
            curRecordSequenceNumber = record["dynamodb"]["SequenceNumber"]
        except Exception as e:
            # Return failed record's sequence number
            return {"batchItemFailures":[{"itemIdentifier": curRecordSequenceNumber}]}

    return {"batchItemFailures":[]}