Lambda Proxy Integration with Cloudformation tamplate

lambda-proxy-integration.yml

apiGateway:
    Type: "AWS::ApiGateway::RestApi"
    Properties:
      Name: "example-api-gw"
      Description: "Example API"

  ProxyResource:
    Type: "AWS::ApiGateway::Resource"
    Properties:
      ParentId: !GetAtt apiGateway.RootResourceId
      RestApiId: !Ref apiGateway
      PathPart: '{proxy+}'

  apiGatewayRootMethod:
    Type: "AWS::ApiGateway::Method"
    Properties:
      AuthorizationType: NONE
      HttpMethod: ANY
      Integration:
        IntegrationHttpMethod: POST
        Type: AWS_PROXY
        IntegrationResponses:
          -
            StatusCode: 200
        Uri: !Sub
          - "arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${lambdaArn}/invocations"
          - lambdaArn: !GetAtt "lambdaFunction.Arn"
      ResourceId: !Ref ProxyResource
      RestApiId: !Ref "apiGateway"


  apiGatewayDeployment:
    Type: "AWS::ApiGateway::Deployment"
    DependsOn:
      - "apiGatewayRootMethod"
    Properties:
      RestApiId: !Ref "apiGateway"
      StageName: !Ref "apiGatewayStageName"

  lambdaFunction:
    Type: "AWS::Lambda::Function"
    Properties:
      Code:
        ZipFile: |
          def handler(event,context):
            return {
              'body': 'Hello there {0}'.format(event['requestContext']['identity']['sourceIp']),
              'headers': {
                'Content-Type': 'text/plain'
              },
              'statusCode': 200
            }
      Description: "Node.js Express REST API with a package called aws-serverless-express"
      FunctionName: !Ref "lambdaFunctionName"
      Handler: lambda.handler
      Runtime: nodejs8.10
      MemorySize: 128
      Role: !GetAtt "lambdaIAMRole.Arn"
      Timeout: 60

  lambdaApiGatewayInvoke:
    Type: "AWS::Lambda::Permission"
    Properties:
      Action: "lambda:InvokeFunction"
      FunctionName: !GetAtt "lambdaFunction.Arn"
      Principal: "apigateway.amazonaws.com"
      SourceArn: !Sub "arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${apiGateway}/*/*/*"

  lambdaIAMRole:
    Type: "AWS::IAM::Role"
    Properties:
      AssumeRolePolicyDocument:
        Version: "2012-10-17"
        Statement:
          - Action:
              - "sts:AssumeRole"
            Effect: "Allow"
            Principal:
              Service:
                - "lambda.amazonaws.com"
      Policies:
        - PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Action:
                  - "logs:CreateLogGroup"
                  - "logs:CreateLogStream"
                  - "logs:PutLogEvents"
                Effect: "Allow"
                Resource:
                  - !Sub "arn:aws:logs:${AWS::Region}:${AWS::AccountId}:log-group:/aws/lambda/${lambdaFunctionName}:*"
          PolicyName: "lambda"
        - PolicyDocument:
            Version: "2012-10-17"
            Statement:
              - Action:
                  - "logs:CreateLogGroup"
                  - "logs:CreateLogStream"
                  - "logs:PutLogEvents"
                  - "ec2:CreateNetworkInterface"
                  - "ec2:DescribeNetworkInterfaces"
                  - "ec2:DeleteNetworkInterface"
                Effect: "Allow"
                Resource: "*"
          PolicyName: "lambdaVPC"
      

  lambdaLogGroup:
    Type: "AWS::Logs::LogGroup"
    Properties:
      LogGroupName: !Sub "/aws/lambda/${lambdaFunctionName}"
      RetentionInDays: 90

Getting a formatting error when pasting your template: