Cloudformation Topic to GoogleChat Webhook

gistfile1.txt

AWSTemplateFormatVersion: '2010-09-09'
Description: 'Alarms to GoogleChat'
Metadata:
  AWS::CloudFormation::Interface:
    ParameterGroups:
    - Label:
        default: General
      Parameters:
      - Environment
    - Label:
        default: Referenced Stacks
      Parameters:
      - AlarmStack
    - Label:
        default: Alerts
      Parameters:
      - HangoutsHookUrl
Parameters:
  AlarmStack:
    Description: Stack tht 
    Type: String
    AllowedPattern: ^$|^[a-zA-Z][-a-zA-Z0-9]*$
  HangoutsHookUrl:
    Description: Hook url to send alerts to hangouts
    Type: String
    NoEcho: true
Conditions:
  AlarmStackOn: !Not [!Equals [!Ref AlarmStack,'']]
Resources:    
  AlarmLambdaRole:
    Type: "AWS::IAM::Role"
    Properties: 
      Path: "/"
      ManagedPolicyArns:
          - "arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole"
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          -
            Sid: "AllowLambdaServiceToAssumeRole"
            Effect: "Allow"
            Action: 
              - "sts:AssumeRole"
            Principal:
              Service: 
                - "lambda.amazonaws.com"
  AlarmLambdaFunction:
    Type: "AWS::Lambda::Function"
    Properties: 
      Code:
        ZipFile: |
          from __future__ import print_function
          
          import boto3
          import json
          import logging
          import os
          
          from base64 import b64decode
          from urllib.request import Request, urlopen
          from urllib.error import URLError, HTTPError

          HOOK_URL = os.environ['HookUrl']
          
          logger = logging.getLogger()
          logger.setLevel(logging.INFO)
          
          def handler(event, context):
            logger.info("Event: " + json.dumps(event))
            message = json.loads(event['Records'][0]['Sns']['Message'])
          
            alarm_name = message['AlarmName']
            alarm_description = message['AlarmDescription']
            old_state = message['OldStateValue']
            new_state = message['NewStateValue']
            reason = message['NewStateReason']
              
            if (old_state == new_state):
              logger.info("State did not change for %s.", alarm_name)
              return
              
            if HOOK_URL == '':
              logger.info("State change from %s to %s for alarm %s, but notification url not set.", old_state, new_state, alarm_name)
              return
              
            request_headers = { 'Content-Type': 'application/json; charset=UTF-8'}
              
            font_color = '#008000' if new_state == 'OK' else '#FF0000'
            status = '<b><font color="' + font_color + '">' + new_state + '</font></b>'
            link = 'https://console.aws.amazon.com/cloudwatch/home?region=us-east-1#alarmsV2:alarm/' + alarm_name + '?'
              
            message = {
              "cards": [{
                "sections": [{
                  "widgets": [{
                    "keyValue": {
                      "topLabel": "Status",
                      "content": "%s" % (status),
                      "contentMultiline": True
                    }
                  },{
                    "keyValue": {
                      "topLabel": "Description",
                      "content": "%s" % (alarm_description),
                      "contentMultiline": True
                    }
                  },{
                    "keyValue": {
                      "topLabel": "Alarm Name",
                      "content": "%s" % (alarm_name),
                      "contentMultiline": True
                    }
                  },{
                    "keyValue": {
                      "topLabel": "Alarm Reason",
                      "content": "%s" % (reason),
                      "contentMultiline": True
                    }
                  }]
                },{
                  "widgets": [{
                    "buttons": [{
                      "textButton": {
                        "text": "Abrir no console",
                        "onClick": {
                          "openLink": {
                            "url": "%s" % (link)
                          }
                        }
                      }
                    }]
                  }]
                }]
              }]
            }
          
            req = Request(HOOK_URL, data=json.dumps(message).encode('utf-8'), headers=request_headers)
            try:
              response = urlopen(req)
              response.read()
              logger.info("Message posted to %s", HOOK_URL)
            except HTTPError as e:
              logger.error("Request to %s failed: %d %s", HOOK_URL, e.code, e.reason)
            except URLError as e:
              logger.error("Server connection to %s failed: %s", HOOK_URL, e.reason)
      Description: Sends alerts to mythbusters at hangouts
      Environment:
        Variables:
          HookUrl: !Ref 'HangoutsHookUrl'
      Handler: index.handler
      MemorySize: 128
      Role: !GetAtt ['AlarmLambdaRole', Arn]
      Runtime: python3.8
      Timeout: 3
      TracingConfig:
        Mode: PassThrough
  AlertsSnsTopicAlarmLambdaFunctionSubscription:
    Type: AWS::SNS::Subscription
    Condition: AlarmStackOn
    Properties:
      Endpoint: !GetAtt [AlarmLambdaFunction, Arn]
      Protocol: lambda
      TopicArn: 
        Fn::ImportValue: 
          !Sub "${AlarmStack}-AlarmTopic"  
  AlarmLambdaInvokePermission: 
    Type: AWS::Lambda::Permission
    Condition: AlarmStackOn
    Properties: 
      Action: lambda:InvokeFunction
      Principal: sns.amazonaws.com
      SourceArn: 
        Fn::ImportValue: !Sub "${AlarmStack}-AlarmTopic"
      FunctionName: !Ref AlarmLambdaFunction

AWS Alarms Google Chat Webhook notification

The ideia here is that you have a Cloudformation exporting a SNS AlarmTopic.