# Copyright 2020 Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: MIT-0

AWSTemplateFormatVersion: '2010-09-09'

Parameters:
  pApp:
    Description: Provide the name of the app component
    Type: String
  pAppURL:
    Description: URL of the application Site to be tested after deployment
    Type: String 
  pAppTestingString:
    Description: String expected to be tested on the Application Site URL page 
    Type: String     

Resources:
  rAfterInstallHookLambdaRole:
    Type: AWS::IAM::Role
    Properties:
      RoleName: !Sub "${pApp}-codedeploy-lifecyclehook-lambda-role"
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
        - Effect: Allow
          Principal:
            Service:
            - lambda.amazonaws.com
          Action:
          - sts:AssumeRole
      Path: /
      ManagedPolicyArns:
        - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole
      Policies:
      - PolicyName: !Sub "${pApp}-codedeploy-lifecyclehook-lambda-policy"
        PolicyDocument:
          Version: '2012-10-17'
          Statement:
          - Effect: Allow
            Action: 
              - 'codedeploy:PutLifecycleEventHookExecutionStatus'
            Resource: '*'

  rAfterInstallHookLambda:
    Type: "AWS::Lambda::Function"
    Properties:
      FunctionName: !Sub "${pApp}-codedeploy-afterinstall-hook-lambda"
      Description: This function tests the deployed application as a AfterInstall Hook
      Handler: index.lambda_handler
      Code:
        ZipFile: |
          import os
          from datetime import datetime
          from urllib.request import Request, urlopen
          import json
          import ssl
          import boto3

          SITE = os.environ['site_url']  # URL of the site to check, stored in the site environment variable
          EXPECTED = os.environ['page_expected_string']  # String expected to be on the page, stored in the expected environment variable

          ctx = ssl.create_default_context()
          ctx.check_hostname = False
          ctx.verify_mode = ssl.CERT_NONE

          codedeploy = boto3.client('codedeploy')

          def send_status(deploymentId, hooksExecutionId, status):
              response = codedeploy.put_lifecycle_event_hook_execution_status(
                              deploymentId=deploymentId,
                              lifecycleEventHookExecutionId=hooksExecutionId,
                              status=status
                          )

          def validate(res):
              '''Return False to trigger the canary

              Currently this simply checks whether the EXPECTED string is present.
              However, you could modify this to perform any number of arbitrary
              checks on the contents of SITE.
              '''
              return EXPECTED in res

          def lambda_handler(event, context):
              print(json.dumps(event))
              status = 'Succeeded'
              deploymentId = event['DeploymentId']
              hooksExecutionId = event['LifecycleEventHookExecutionId']
              #print('Checking {} at {}...'.format(SITE, event['time']))
              try:
                  req = Request(SITE, headers={'User-Agent': 'AWS Lambda'})
                  if not validate(str(urlopen(req, context=ctx).read())):
                      status = 'Failed'
              except:
                  print('Check failed!')
                  status = 'Failed'
              else:
                  print('Check passed!')
                  return str(datetime.now())
              finally:
                  send_status(deploymentId, hooksExecutionId, status)
                  print('Check complete at {}'.format(str(datetime.now())))

      Runtime: python3.8
      Role: !GetAtt rAfterInstallHookLambdaRole.Arn
      Timeout: 30
      MemorySize: 512
      Environment:
        Variables: 
          site_url: !Ref pAppURL
          page_expected_string: !Ref pAppTestingString

Outputs:
  oAfterInstallHookLambdaArn:
    Description: AfterInstallHookLambda ARN
    Value: !GetAtt rAfterInstallHookLambda.Arn