自动创建监控告警 – Lambda 1

from __future__ import print_function
import logging
import os
import json
import boto3

RDS_MetricName = "DatabaseConnections"  # os.environ['MetricName']
MaxItems = 3  # os.environ['MaxItems']
SNS_topic_suffix = "RDS_DatabaseConnections"  # os.environ['SNS_topic_suffix']

logger = logging.getLogger()
logger.setLevel(logging.INFO)

instance_connection = {
    "large": 1000,
    "xlarge": 2000,
    "2xlarge": 3000,
    "4xlarge": 5000,
    "8xlarge": 10000,
    "12xlarge": 15000,
    "16xlarge": 20000,
    "24xlarge": 30000,
    "small": 45,
    "medium": 90
}


# The 'handler' Python function is the entry point for AWS Lambda function invocations.
def lambda_handler(event, context):
    stsClient = boto3.client('sts')
    accountId = stsClient.get_caller_identity().get('Account')
    print('------')
    print('Account: ' + accountId)

    #   List metrics through the pagination interface
    CW_client = boto3.client('cloudwatch')
    CW_paginator = CW_client.get_paginator('describe_alarms')
    CW_iterator = CW_paginator.paginate()
    CW_filteredIterator = CW_iterator.search(
        "MetricAlarms[?MetricName==`" + RDS_MetricName + "` && Namespace==`AWS/RDS`]")

    #   Prepare target RDS list
    RDS_client = boto3.client('rds')
    RDS_paginator = RDS_client.get_paginator('describe_db_instances')
    RDS_iterator = RDS_paginator.paginate(
        PaginationConfig={
            # 最大创建RDS CloudWatch alarms的数量
            'MaxItems': MaxItems,
            # 演示分页，最小20，最大100
            'PageSize': 100
        }
    )

    #   Prepare RDS full list
    print('------')
    print('RDS full list:')
    RDS_rawList = []
    RDS_nameList = []
    #    RDS_idList = []
    for RDS_response in RDS_iterator:
        RDS_rawList.extend(RDS_response['DBInstances'])
    for dict in RDS_rawList:
        for i in dict.items():
            if i[0] == "DBInstanceIdentifier":
                print(i[1])
                RDS_nameList.append(i[1])
    #                RDS_idList.append(i[1].split('/',1)[1])

    #   Prepare RDS ignore list: 筛选出已经创建对应监控告警的RDS数据库实例
    print('------')
    print('RDS ignore list:')
    RDS_ignoreList = []
    for alarm in CW_filteredIterator:
        #       判断已有的监控告警是否为正准备创建的监控告警
        if alarm['MetricName'] == RDS_MetricName:
            for dimension in alarm["Dimensions"]:
                if dimension["Name"] == "DBInstanceIdentifier":
                    RDS_ignoreList.append(dimension["Value"])
                    print(dimension["Value"])

    #   Drop CloudWatch alarm cascade:
    print('------')
    for cw in RDS_ignoreList:
        if cw in RDS_nameList:
            print('Dropping CloudWatch alarm "RDS_' + RDS_MetricName + '" for: ' + cw)
            CWalarms = CW_client.delete_alarms(
                AlarmNames=['RDS_' + RDS_MetricName + '-' + cw]
            )
            print('Dropped CloudWatch alarm "RDS_' + RDS_MetricName + '" for: ' + cw)

    #   Create customized CloudWatch alarms auto:
    print('')
    for rds_record in RDS_rawList:
        #       预先定义SNS topic suffix，不同的CloudWatch告警通知会发送到不同的SNS topic
        rds_name = rds_record['DBInstanceArn'].split(':', 6)[6]
        print('------')
        #       判断是否为MySQL数据库，且未创建对应的监控告警
        if (rds_name not in RDS_ignoreList) and (RDS_rawList[0]['Engine'] == 'mysql'):
            print('------')
            print('RDS name: ' + rds_name)
            print('Creating CloudWatch alarm "RDS_' + RDS_MetricName + '" for: ' + rds_name)
            #           获取该RDS数据库对应的实例规格，查询map_maxConnections mapping所对应的max_connections
            for dict in RDS_rawList:
                if dict["DBInstanceIdentifier"] == rds_name:
                    max_connections = instance_connection[dict["DBInstanceClass"].split('.', 2)[2]]
                    print('max_connections = ' + str(max_connections))
            #           创建监控告警
            CWalarms = CW_client.put_metric_alarm(
                AlarmName='RDS_' + RDS_MetricName + '-' + rds_name,
                AlarmDescription='Auto-created customized CloudWatch Alarm <RDS_' + RDS_MetricName + '>',
                ActionsEnabled=True,
                #                OKActions=[
                #                    'string',
                #                ],
                AlarmActions=[
                    # 示例，发送到SNS
                    'arn:aws:sns:us-west-2:{}:customizedAlarmAction-{}'.format(accountId, SNS_topic_suffix)
                ],
                #                InsufficientDataActions=[
                #                    'string',
                #                ],
                MetricName=RDS_MetricName,
                Namespace="AWS/RDS",
                Statistic='Maximum',
                # 'SampleCount'|'Average'|'Sum'|'Minimum'|'Maximum'
                #                ExtendedStatistic='p100',
                Dimensions=[
                    {
                        'Name': 'DBInstanceIdentifier',
                        'Value': rds_name
                    },
                ],
                Period=60,
                #                Unit='Seconds',
                # 'Seconds'|'Microseconds'|'Milliseconds'|'Bytes'|'Kilobytes'|'Megabytes'|'Gigabytes'|'Terabytes'|'Bits'|'Kilobits'|'Megabits'|'Gigabits'|'Terabits'|'Percent'|'Count'|'Bytes/Second'|'Kilobytes/Second'|'Megabytes/Second'|'Gigabytes/Second'|'Terabytes/Second'|'Bits/Second'|'Kilobits/Second'|'Megabits/Second'|'Gigabits/Second'|'Terabits/Second'|'Count/Second'|'None'
                EvaluationPeriods=3,
                DatapointsToAlarm=2,
                Threshold=max_connections,
                ComparisonOperator='GreaterThanThreshold',
                # 'GreaterThanOrEqualToThreshold'|'GreaterThanThreshold'|'LessThanThreshold'|'LessThanOrEqualToThreshold'|'LessThanLowerOrGreaterThanUpperThreshold'|'LessThanLowerThreshold'|'GreaterThanUpperThreshold'
                TreatMissingData='ignore',

                Tags=[
                    {
                        'Key': str('RDS_' + RDS_MetricName),
                        'Value': 'autocreated'
                    },
                ],
                #                ThresholdMetricId='string'
            )

            #           为该RDS数据库标记CWalarm-DatabaseConnections标签
            RDS_tags = RDS_client.add_tags_to_resource(
                ResourceName=rds_record['DBInstanceArn'],
                Tags=[
                    {
                        'Key': str('CWalarm-' + RDS_MetricName),
                        'Value': 'enabled'
                    },
                ]
            )
            print('Added tag "CWalarm-' + RDS_MetricName + '" to: ' + rds_name)

            print('Created CloudWatch alarm "RDS_' + RDS_MetricName + '" for: ' + rds_name)
            print()
        else:
            print('No CloudWatch alarm created for: ' + rds_name)
    return {
        'statusCode': 200,
        'body': json.dumps('Mission Complete!')
    }