# Gerenciar métricas e alarmes do CloudWatch usando um AWS SDK O código de exemplo abaixo mostra como: + Criar um alarme para observar uma métrica do CloudWatch. + Inserir dados em uma métrica e acionar o alarme. + Obter dados do alarme. + Excluir o alarme. ------ #### [ Python ] **SDK para Python (Boto3).** Há mais no GitHub. Encontre o exemplo completo e saiba como configurar e executar no [AWS Code Examples Repository](https://github.com/awsdocs/aws-doc-sdk-examples/tree/main/python/example_code/cloudwatch#code-examples). Crie uma classe que envolva operações do CloudWatch. ``` from datetime import datetime, timedelta import logging from pprint import pprint import random import time import boto3 from botocore.exceptions import ClientError logger = logging.getLogger(__name__) class CloudWatchWrapper: """Encapsulates Amazon CloudWatch functions.""" def __init__(self, cloudwatch_resource): """ :param cloudwatch_resource: A Boto3 CloudWatch resource. """ self.cloudwatch_resource = cloudwatch_resource def put_metric_data_set(self, namespace, name, timestamp, unit, data_set): """ Sends a set of data to CloudWatch for a metric. All of the data in the set have the same timestamp and unit. :param namespace: The namespace of the metric. :param name: The name of the metric. :param timestamp: The UTC timestamp for the metric. :param unit: The unit of the metric. :param data_set: The set of data to send. This set is a dictionary that contains a list of values and a list of corresponding counts. The value and count lists must be the same length. """ try: metric = self.cloudwatch_resource.Metric(namespace, name) metric.put_data( Namespace=namespace, MetricData=[ { "MetricName": name, "Timestamp": timestamp, "Values": data_set["values"], "Counts": data_set["counts"], "Unit": unit, } ], ) logger.info("Put data set for metric %s.%s.", namespace, name) except ClientError: logger.exception("Couldn't put data set for metric %s.%s.", namespace, name) raise def create_metric_alarm( self, metric_namespace, metric_name, alarm_name, stat_type, period, eval_periods, threshold, comparison_op, ): """ Creates an alarm that watches a metric. :param metric_namespace: The namespace of the metric. :param metric_name: The name of the metric. :param alarm_name: The name of the alarm. :param stat_type: The type of statistic the alarm watches. :param period: The period in which metric data are grouped to calculate statistics. :param eval_periods: The number of periods that the metric must be over the alarm threshold before the alarm is set into an alarmed state. :param threshold: The threshold value to compare against the metric statistic. :param comparison_op: The comparison operation used to compare the threshold against the metric. :return: The newly created alarm. """ try: metric = self.cloudwatch_resource.Metric(metric_namespace, metric_name) alarm = metric.put_alarm( AlarmName=alarm_name, Statistic=stat_type, Period=period, EvaluationPeriods=eval_periods, Threshold=threshold, ComparisonOperator=comparison_op, ) logger.info( "Added alarm %s to track metric %s.%s.", alarm_name, metric_namespace, metric_name, ) except ClientError: logger.exception( "Couldn't add alarm %s to metric %s.%s", alarm_name, metric_namespace, metric_name, ) raise else: return alarm def put_metric_data(self, namespace, name, value, unit): """ Sends a single data value to CloudWatch for a metric. This metric is given a timestamp of the current UTC time. :param namespace: The namespace of the metric. :param name: The name of the metric. :param value: The value of the metric. :param unit: The unit of the metric. """ try: metric = self.cloudwatch_resource.Metric(namespace, name) metric.put_data( Namespace=namespace, MetricData=[{"MetricName": name, "Value": value, "Unit": unit}], ) logger.info("Put data for metric %s.%s", namespace, name) except ClientError: logger.exception("Couldn't put data for metric %s.%s", namespace, name) raise def get_metric_statistics(self, namespace, name, start, end, period, stat_types): """ Gets statistics for a metric within a specified time span. Metrics are grouped into the specified period. :param namespace: The namespace of the metric. :param name: The name of the metric. :param start: The UTC start time of the time span to retrieve. :param end: The UTC end time of the time span to retrieve. :param period: The period, in seconds, in which to group metrics. The period must match the granularity of the metric, which depends on the metric's age. For example, metrics that are older than three hours have a one-minute granularity, so the period must be at least 60 and must be a multiple of 60. :param stat_types: The type of statistics to retrieve, such as average value or maximum value. :return: The retrieved statistics for the metric. """ try: metric = self.cloudwatch_resource.Metric(namespace, name) stats = metric.get_statistics( StartTime=start, EndTime=end, Period=period, Statistics=stat_types ) logger.info( "Got %s statistics for %s.", len(stats["Datapoints"]), stats["Label"] ) except ClientError: logger.exception("Couldn't get statistics for %s.%s.", namespace, name) raise else: return stats def get_metric_alarms(self, metric_namespace, metric_name): """ Gets the alarms that are currently watching the specified metric. :param metric_namespace: The namespace of the metric. :param metric_name: The name of the metric. :returns: An iterator that yields the alarms. """ metric = self.cloudwatch_resource.Metric(metric_namespace, metric_name) alarm_iter = metric.alarms.all() logger.info("Got alarms for metric %s.%s.", metric_namespace, metric_name) return alarm_iter def delete_metric_alarms(self, metric_namespace, metric_name): """ Deletes all of the alarms that are currently watching the specified metric. :param metric_namespace: The namespace of the metric. :param metric_name: The name of the metric. """ try: metric = self.cloudwatch_resource.Metric(metric_namespace, metric_name) metric.alarms.delete() logger.info( "Deleted alarms for metric %s.%s.", metric_namespace, metric_name ) except ClientError: logger.exception( "Couldn't delete alarms for metric %s.%s.", metric_namespace, metric_name, ) raise ``` Use a classe criada para colocar dados em uma métrica, acionar um alarme que observa a métrica e obter dados do alarme. ``` def usage_demo(): print("-" * 88) print("Welcome to the Amazon CloudWatch metrics and alarms demo!") print("-" * 88) logging.basicConfig(level=logging.INFO, format="%(levelname)s: %(message)s") cw_wrapper = CloudWatchWrapper(boto3.resource("cloudwatch")) minutes = 20 metric_namespace = "doc-example-metric" metric_name = "page_views" start = datetime.utcnow() - timedelta(minutes=minutes) print( f"Putting data into metric {metric_namespace}.{metric_name} spanning the " f"last {minutes} minutes." ) for offset in range(0, minutes): stamp = start + timedelta(minutes=offset) cw_wrapper.put_metric_data_set( metric_namespace, metric_name, stamp, "Count", { "values": [ random.randint(bound, bound * 2) for bound in range(offset + 1, offset + 11) ], "counts": [random.randint(1, offset + 1) for _ in range(10)], }, ) alarm_name = "high_page_views" period = 60 eval_periods = 2 print(f"Creating alarm {alarm_name} for metric {metric_name}.") alarm = cw_wrapper.create_metric_alarm( metric_namespace, metric_name, alarm_name, "Maximum", period, eval_periods, 100, "GreaterThanThreshold", ) print(f"Alarm ARN is {alarm.alarm_arn}.") print(f"Current alarm state is: {alarm.state_value}.") print( f"Sending data to trigger the alarm. This requires data over the threshold " f"for {eval_periods} periods of {period} seconds each." ) while alarm.state_value == "INSUFFICIENT_DATA": print("Sending data for the metric.") cw_wrapper.put_metric_data( metric_namespace, metric_name, random.randint(100, 200), "Count" ) alarm.load() print(f"Current alarm state is: {alarm.state_value}.") if alarm.state_value == "INSUFFICIENT_DATA": print(f"Waiting for {period} seconds...") time.sleep(period) else: print("Wait for a minute for eventual consistency of metric data.") time.sleep(period) if alarm.state_value == "OK": alarm.load() print(f"Current alarm state is: {alarm.state_value}.") print( f"Getting data for metric {metric_namespace}.{metric_name} during timespan " f"of {start} to {datetime.utcnow()} (times are UTC)." ) stats = cw_wrapper.get_metric_statistics( metric_namespace, metric_name, start, datetime.utcnow(), 60, ["Average", "Minimum", "Maximum"], ) print( f"Got {len(stats['Datapoints'])} data points for metric " f"{metric_namespace}.{metric_name}." ) pprint(sorted(stats["Datapoints"], key=lambda x: x["Timestamp"])) print(f"Getting alarms for metric {metric_name}.") alarms = cw_wrapper.get_metric_alarms(metric_namespace, metric_name) for alarm in alarms: print(f"Alarm {alarm.name} is currently in state {alarm.state_value}.") print(f"Deleting alarms for metric {metric_name}.") cw_wrapper.delete_metric_alarms(metric_namespace, metric_name) print("Thanks for watching!") print("-" * 88) ``` + Para obter detalhes da API, consulte os tópicos a seguir na *Referência da API AWS SDK para Python (Boto3)*. + [DeleteAlarms](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/DeleteAlarms) + [DescribeAlarmsForMetric](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/DescribeAlarmsForMetric) + [DisableAlarmActions](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/DisableAlarmActions) + [EnableAlarmActions](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/EnableAlarmActions) + [GetMetricStatistics](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/GetMetricStatistics) + [ListMetrics](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/ListMetrics) + [PutMetricAlarm](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/PutMetricAlarm) + [PutMetricData](https://docs.aws.amazon.com/goto/boto3/monitoring-2010-08-01/PutMetricData) ------ Para ver uma lista completa dos guias de desenvolvedor e exemplos de código do SDK da AWS, consulte [Como usar o CloudWatch com um AWS SDK](sdk-general-information-section.md). Este tópico também inclui informações sobre como começar e detalhes sobre versões anteriores do SDK.