[適用於 JavaScript 的 AWS SDK V3 API 參考指南](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/)詳細說明 第 3 版 適用於 JavaScript 的 AWS SDK (V3) 的所有 API 操作。
本文為英文版的機器翻譯版本，如內容有任何歧義或不一致之處，概以英文版為準。
# 使用適用於 JavaScript 的 SDK (v3) 的 CloudWatch Logs 範例
下列程式碼範例示範如何使用 適用於 JavaScript 的 AWS SDK (v3) 搭配 CloudWatch Logs 來執行動作和實作常見案例。
*Actions* 是大型程式的程式碼摘錄，必須在內容中執行。雖然動作會告訴您如何呼叫個別服務函數，但您可以在其相關情境中查看內容中的動作。
*案例*是向您展示如何呼叫服務中的多個函數或與其他 AWS 服務組合來完成特定任務的程式碼範例。
每個範例均包含完整原始碼的連結，您可在連結中找到如何設定和執行內容中程式碼的相關指示。
**Topics**
+ [動作](#actions)
+ [案例](#scenarios)
## 動作
### `CreateLogGroup`
以下程式碼範例顯示如何使用 `CreateLogGroup`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
import { CreateLogGroupCommand } from "@aws-sdk/client-cloudwatch-logs";
import { client } from "../libs/client.js";
const run = async () => {
const command = new CreateLogGroupCommand({
// The name of the log group.
logGroupName: process.env.CLOUDWATCH_LOGS_LOG_GROUP,
});
try {
return await client.send(command);
} catch (err) {
console.error(err);
}
};
export default run();
```
+ 如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [CreateLogGroup](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/CreateLogGroupCommand)。
### `DeleteLogGroup`
以下程式碼範例顯示如何使用 `DeleteLogGroup`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
import { DeleteLogGroupCommand } from "@aws-sdk/client-cloudwatch-logs";
import { client } from "../libs/client.js";
const run = async () => {
const command = new DeleteLogGroupCommand({
// The name of the log group.
logGroupName: process.env.CLOUDWATCH_LOGS_LOG_GROUP,
});
try {
return await client.send(command);
} catch (err) {
console.error(err);
}
};
export default run();
```
+ 如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [DeleteLogGroup](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/DeleteLogGroupCommand)。
### `DeleteSubscriptionFilter`
以下程式碼範例顯示如何使用 `DeleteSubscriptionFilter`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
import { DeleteSubscriptionFilterCommand } from "@aws-sdk/client-cloudwatch-logs";
import { client } from "../libs/client.js";
const run = async () => {
const command = new DeleteSubscriptionFilterCommand({
// The name of the filter.
filterName: process.env.CLOUDWATCH_LOGS_FILTER_NAME,
// The name of the log group.
logGroupName: process.env.CLOUDWATCH_LOGS_LOG_GROUP,
});
try {
return await client.send(command);
} catch (err) {
console.error(err);
}
};
export default run();
```
+ 如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [DeleteSubscriptionFilter](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/DeleteSubscriptionFilterCommand)。
### `DescribeLogGroups`
以下程式碼範例顯示如何使用 `DescribeLogGroups`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
import {
paginateDescribeLogGroups,
CloudWatchLogsClient,
} from "@aws-sdk/client-cloudwatch-logs";
const client = new CloudWatchLogsClient({});
export const main = async () => {
const paginatedLogGroups = paginateDescribeLogGroups({ client }, {});
const logGroups = [];
for await (const page of paginatedLogGroups) {
if (page.logGroups?.every((lg) => !!lg)) {
logGroups.push(...page.logGroups);
}
}
console.log(logGroups);
return logGroups;
};
```
+ 如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [DescribeLogGroups](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/DescribeLogGroupsCommand)。
### `DescribeSubscriptionFilters`
以下程式碼範例顯示如何使用 `DescribeSubscriptionFilters`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
import { DescribeSubscriptionFiltersCommand } from "@aws-sdk/client-cloudwatch-logs";
import { client } from "../libs/client.js";
const run = async () => {
// This will return a list of all subscription filters in your account
// matching the log group name.
const command = new DescribeSubscriptionFiltersCommand({
logGroupName: process.env.CLOUDWATCH_LOGS_LOG_GROUP,
limit: 1,
});
try {
return await client.send(command);
} catch (err) {
console.error(err);
}
};
export default run();
```
+ 如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [DescribeSubscriptionFilters](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/DescribeSubscriptionFiltersCommand)。
### `GetQueryResults`
以下程式碼範例顯示如何使用 `GetQueryResults`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
/**
* Simple wrapper for the GetQueryResultsCommand.
* @param {string} queryId
*/
_getQueryResults(queryId) {
return this.client.send(new GetQueryResultsCommand({ queryId }));
}
```
+ 如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [GetQueryResults](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/GetQueryResultsCommand)。
### `PutSubscriptionFilter`
以下程式碼範例顯示如何使用 `PutSubscriptionFilter`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
import { PutSubscriptionFilterCommand } from "@aws-sdk/client-cloudwatch-logs";
import { client } from "../libs/client.js";
const run = async () => {
const command = new PutSubscriptionFilterCommand({
// An ARN of a same-account Kinesis stream, Kinesis Firehose
// delivery stream, or Lambda function.
// https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/SubscriptionFilters.html
destinationArn: process.env.CLOUDWATCH_LOGS_DESTINATION_ARN,
// A name for the filter.
filterName: process.env.CLOUDWATCH_LOGS_FILTER_NAME,
// A filter pattern for subscribing to a filtered stream of log events.
// https://docs.aws.amazon.com/AmazonCloudWatch/latest/logs/FilterAndPatternSyntax.html
filterPattern: process.env.CLOUDWATCH_LOGS_FILTER_PATTERN,
// The name of the log group. Messages in this group matching the filter pattern
// will be sent to the destination ARN.
logGroupName: process.env.CLOUDWATCH_LOGS_LOG_GROUP,
});
try {
return await client.send(command);
} catch (err) {
console.error(err);
}
};
export default run();
```
+ 如需 API 詳細資訊，請參閱*《適用於 JavaScript 的 AWS SDK API 參考》*中的 [PutSubscriptionFilter](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/PutSubscriptionFilterCommand)。
### `StartLiveTail`
以下程式碼範例顯示如何使用 `StartLiveTail`。
**適用於 JavaScript (v3) 的 SDK**
包括必需的檔案。
```
import { CloudWatchLogsClient, StartLiveTailCommand } from "@aws-sdk/client-cloudwatch-logs";
```
處理 Live Tail 工作階段的事件。
```
async function handleResponseAsync(response) {
try {
for await (const event of response.responseStream) {
if (event.sessionStart !== undefined) {
console.log(event.sessionStart);
} else if (event.sessionUpdate !== undefined) {
for (const logEvent of event.sessionUpdate.sessionResults) {
const timestamp = logEvent.timestamp;
const date = new Date(timestamp);
console.log("[" + date + "] " + logEvent.message);
}
} else {
console.error("Unknown event type");
}
}
} catch (err) {
// On-stream exceptions are captured here
console.error(err)
}
}
```
開始 Live Tail 工作階段。
```
const client = new CloudWatchLogsClient();
const command = new StartLiveTailCommand({
logGroupIdentifiers: logGroupIdentifiers,
logStreamNames: logStreamNames,
logEventFilterPattern: filterPattern
});
try{
const response = await client.send(command);
handleResponseAsync(response);
} catch (err){
// Pre-stream exceptions are captured here
console.log(err);
}
```
在經過一段時間後停止 Live Tail 工作階段。
```
/* Set a timeout to close the client. This will stop the Live Tail session. */
setTimeout(function() {
console.log("Client timeout");
client.destroy();
}, 10000);
```
+ 如需 API 詳細資訊，請參閱《*適用於 JavaScript 的 AWS SDK API 參考*》中的 [StartLiveTail](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/StartLiveTailCommand)。
### `StartQuery`
以下程式碼範例顯示如何使用 `StartQuery`。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs#code-examples)中設定和執行。
```
/**
* Wrapper for the StartQueryCommand. Uses a static query string
* for consistency.
* @param {[Date, Date]} dateRange
* @param {number} maxLogs
* @returns {Promise<{ queryId: string }>}
*/
async _startQuery([startDate, endDate], maxLogs = 10000) {
try {
return await this.client.send(
new StartQueryCommand({
logGroupNames: this.logGroupNames,
queryString: "fields @timestamp, @message | sort @timestamp asc",
startTime: startDate.valueOf(),
endTime: endDate.valueOf(),
limit: maxLogs,
}),
);
} catch (err) {
/** @type {string} */
const message = err.message;
if (message.startsWith("Query's end date and time")) {
// This error indicates that the query's start or end date occur
// before the log group was created.
throw new DateOutOfBoundsError(message);
}
throw err;
}
}
```
+ 如需 API 詳細資訊，請參閱《適用於 JavaScript 的 AWS SDK API 參考》**中的 [StartQuery](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/StartQueryCommand)。
## 案例
### 執行大型查詢
下列程式碼範例示範如何使用 CloudWatch Logs 查詢超過 10,000 筆記錄。
**適用於 JavaScript (v3) 的 SDK**
GitHub 上提供更多範例。尋找完整範例，並了解如何在 [AWS 程式碼範例儲存庫](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cloudwatch-logs/scenarios/large-query#code-examples)中設定和執行。
這是進入點。
```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import { CloudWatchLogsClient } from "@aws-sdk/client-cloudwatch-logs";
import { CloudWatchQuery } from "./cloud-watch-query.js";
console.log("Starting a recursive query...");
if (!process.env.QUERY_START_DATE || !process.env.QUERY_END_DATE) {
throw new Error(
"QUERY_START_DATE and QUERY_END_DATE environment variables are required.",
);
}
const cloudWatchQuery = new CloudWatchQuery(new CloudWatchLogsClient({}), {
logGroupNames: ["/workflows/cloudwatch-logs/large-query"],
dateRange: [
new Date(Number.parseInt(process.env.QUERY_START_DATE)),
new Date(Number.parseInt(process.env.QUERY_END_DATE)),
],
});
await cloudWatchQuery.run();
console.log(
`Queries finished in ${cloudWatchQuery.secondsElapsed} seconds.\nTotal logs found: ${cloudWatchQuery.results.length}`,
);
```
這是一種類別，可在必要時將查詢拆分為多個步驟。
```
// Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
// SPDX-License-Identifier: Apache-2.0
import {
StartQueryCommand,
GetQueryResultsCommand,
} from "@aws-sdk/client-cloudwatch-logs";
import { splitDateRange } from "@aws-doc-sdk-examples/lib/utils/util-date.js";
import { retry } from "@aws-doc-sdk-examples/lib/utils/util-timers.js";
class DateOutOfBoundsError extends Error {}
export class CloudWatchQuery {
/**
* Run a query for all CloudWatch Logs within a certain date range.
* CloudWatch logs return a max of 10,000 results. This class
* performs a binary search across all of the logs in the provided
* date range if a query returns the maximum number of results.
*
* @param {import('@aws-sdk/client-cloudwatch-logs').CloudWatchLogsClient} client
* @param {{ logGroupNames: string[], dateRange: [Date, Date], queryConfig: { limit: number } }} config
*/
constructor(client, { logGroupNames, dateRange, queryConfig }) {
this.client = client;
/**
* All log groups are queried.
*/
this.logGroupNames = logGroupNames;
/**
* The inclusive date range that is queried.
*/
this.dateRange = dateRange;
/**
* CloudWatch Logs never returns more than 10,000 logs.
*/
this.limit = queryConfig?.limit ?? 10000;
/**
* @type {import("@aws-sdk/client-cloudwatch-logs").ResultField[][]}
*/
this.results = [];
}
/**
* Run the query.
*/
async run() {
this.secondsElapsed = 0;
const start = new Date();
this.results = await this._largeQuery(this.dateRange);
const end = new Date();
this.secondsElapsed = (end - start) / 1000;
return this.results;
}
/**
* Recursively query for logs.
* @param {[Date, Date]} dateRange
* @returns {Promise}
*/
async _largeQuery(dateRange) {
const logs = await this._query(dateRange, this.limit);
console.log(
`Query date range: ${dateRange
.map((d) => d.toISOString())
.join(" to ")}. Found ${logs.length} logs.`,
);
if (logs.length < this.limit) {
return logs;
}
const lastLogDate = this._getLastLogDate(logs);
const offsetLastLogDate = new Date(lastLogDate);
offsetLastLogDate.setMilliseconds(lastLogDate.getMilliseconds() + 1);
const subDateRange = [offsetLastLogDate, dateRange[1]];
const [r1, r2] = splitDateRange(subDateRange);
const results = await Promise.all([
this._largeQuery(r1),
this._largeQuery(r2),
]);
return [logs, ...results].flat();
}
/**
* Find the most recent log in a list of logs.
* @param {import("@aws-sdk/client-cloudwatch-logs").ResultField[][]} logs
*/
_getLastLogDate(logs) {
const timestamps = logs
.map(
(log) =>
log.find((fieldMeta) => fieldMeta.field === "@timestamp")?.value,
)
.filter((t) => !!t)
.map((t) => `${t}Z`)
.sort();
if (!timestamps.length) {
throw new Error("No timestamp found in logs.");
}
return new Date(timestamps[timestamps.length - 1]);
}
/**
* Simple wrapper for the GetQueryResultsCommand.
* @param {string} queryId
*/
_getQueryResults(queryId) {
return this.client.send(new GetQueryResultsCommand({ queryId }));
}
/**
* Starts a query and waits for it to complete.
* @param {[Date, Date]} dateRange
* @param {number} maxLogs
*/
async _query(dateRange, maxLogs) {
try {
const { queryId } = await this._startQuery(dateRange, maxLogs);
const { results } = await this._waitUntilQueryDone(queryId);
return results ?? [];
} catch (err) {
/**
* This error is thrown when StartQuery returns an error indicating
* that the query's start or end date occur before the log group was
* created.
*/
if (err instanceof DateOutOfBoundsError) {
return [];
}
throw err;
}
}
/**
* Wrapper for the StartQueryCommand. Uses a static query string
* for consistency.
* @param {[Date, Date]} dateRange
* @param {number} maxLogs
* @returns {Promise<{ queryId: string }>}
*/
async _startQuery([startDate, endDate], maxLogs = 10000) {
try {
return await this.client.send(
new StartQueryCommand({
logGroupNames: this.logGroupNames,
queryString: "fields @timestamp, @message | sort @timestamp asc",
startTime: startDate.valueOf(),
endTime: endDate.valueOf(),
limit: maxLogs,
}),
);
} catch (err) {
/** @type {string} */
const message = err.message;
if (message.startsWith("Query's end date and time")) {
// This error indicates that the query's start or end date occur
// before the log group was created.
throw new DateOutOfBoundsError(message);
}
throw err;
}
}
/**
* Call GetQueryResultsCommand until the query is done.
* @param {string} queryId
*/
_waitUntilQueryDone(queryId) {
const getResults = async () => {
const results = await this._getQueryResults(queryId);
const queryDone = [
"Complete",
"Failed",
"Cancelled",
"Timeout",
"Unknown",
].includes(results.status);
return { queryDone, results };
};
return retry(
{ intervalInMs: 1000, maxRetries: 60, quiet: true },
async () => {
const { queryDone, results } = await getResults();
if (!queryDone) {
throw new Error("Query not done.");
}
return results;
},
);
}
}
```
+ 如需 API 詳細資訊，請參閱《*適用於 JavaScript 的 AWS SDK API 參考*》中的下列主題。
+ [GetQueryResults](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/GetQueryResultsCommand)
+ [StartQuery](https://docs.aws.amazon.com/AWSJavaScriptSDK/v3/latest/client/cloudwatch-logs/command/StartQueryCommand)
### 使用排程事件來調用 Lambda 函式
下列程式碼範例示範如何建立由 Amazon EventBridge 排程事件呼叫的 AWS Lambda 函數。
**適用於 JavaScript (v3) 的 SDK**
顯示如何建立叫用 AWS Lambda 函數的 Amazon EventBridge 排程事件。將 EventBridge 設定為在調用 Lambda 函式時使用 Cron 表達式來進行排程。在此範例中，您會使用 Lambda JavaScript 執行時期 API 建立 Lambda 函式。此範例會叫用不同的 AWS 服務來執行特定的使用案例。此範例示範如何建立應用程式，將行動裝置文字訊息傳送給員工，在他們的週年紀念日向他們道賀。
如需完整的原始碼和如何設定及執行的指示，請參閱 [GitHub](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/javascriptv3/example_code/cross-services/lambda-scheduled-events) 上的完整範例。
此範例也可在 [適用於 JavaScript 的 AWS SDK v3 開發人員指南](https://docs.aws.amazon.com/sdk-for-javascript/v3/developer-guide/scheduled-events-invoking-lambda-example.html)中取得。
**此範例中使用的服務**
+ CloudWatch Logs
+ DynamoDB
+ EventBridge
+ Lambda
+ Amazon SNS