module.yml

---
# Copyright 2018 widdix GmbH
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
AWSTemplateFormatVersion: '2010-09-09'
Description: 'cfn-modules: AWS Lambda event source: webhook'
# cfn-modules:implements()
Parameters:
  LambdaModule:
    Description: 'Stack name of lambda-function module.'
    Type: String
  AlertingModule:
    Description: 'Optional but recommended stack name of alerting module.'
    Type: String
    Default: ''
  HttpMethod:
    Description: 'The HTTP method that clients use to call this method.'
    Type: String
    Default: ANY
    AllowedValues: [ANY, GET, HEAD, POST, PUT, DELETE, OPTIONS]
Conditions:
  HasAlertingModule: !Not [!Equals [!Ref AlertingModule, '']]
Resources:
  Permission:
    Type: 'AWS::Lambda::Permission'
    Properties:
      Action: 'lambda:InvokeFunction'
      FunctionName: {'Fn::ImportValue': !Sub '${LambdaModule}-Name'}
      Principal: 'apigateway.amazonaws.com'
      SourceArn: !Sub 'arn:aws:execute-api:${AWS::Region}:${AWS::AccountId}:${RestApi}/*/${HttpMethod}/'
  RestApi:
    Type: 'AWS::ApiGateway::RestApi'
    Properties:
      Name: !Ref 'AWS::StackName'
  Stage:
    Type: 'AWS::ApiGateway::Stage'
    Properties:
      DeploymentId: !Ref Deployment
      RestApiId: !Ref RestApi
      StageName: webhook
  Deployment:
    DependsOn: Method
    Type: 'AWS::ApiGateway::Deployment'
    Properties:
      RestApiId: !Ref RestApi
  Method:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      AuthorizationType: NONE
      HttpMethod: !Ref HttpMethod
      Integration:
        IntegrationHttpMethod: 'POST'
        PassthroughBehavior: 'WHEN_NO_MATCH'
        Type: 'AWS_PROXY'
        Uri: !Sub
        - 'arn:aws:apigateway:${Region}:lambda:path/2015-03-31/functions/${LambdaFunctionArn}/invocations'
        - Region: !Ref 'AWS::Region'
          LambdaFunctionArn: {'Fn::ImportValue': !Sub '${LambdaModule}-Arn'}
      ResourceId: !GetAtt 'RestApi.RootResourceId'
      RestApiId: !Ref RestApi
  Alarm5XXErrorTooHigh:
    Condition: HasAlertingModule
    Type: 'AWS::CloudWatch::Alarm'
    Properties:
      AlarmDescription: 'Api Gateway server-side errors captured'
      Namespace: 'AWS/ApiGateway'
      MetricName: 5XXError
      Statistic: Sum
      Period: 60
      EvaluationPeriods: 1
      ComparisonOperator: GreaterThanThreshold
      Threshold: 0
      AlarmActions:
      - 'Fn::ImportValue': !Sub '${AlertingModule}-Arn'
      Dimensions:
      - Name: ApiName
        Value: !Ref 'AWS::StackName'
      - Name: Stage
        Value: !Ref Stage
Outputs:
  ModuleId:
    Value: 'lambda-event-source-webhook'
  ModuleVersion:
    Value: '0.0.1'
  StackName:
    Value: !Ref 'AWS::StackName'
  Url:
    Value: !Sub 'https://${RestApi}.execute-api.${AWS::Region}.amazonaws.com/${Stage}'
    Export:
      Name: !Sub '${AWS::StackName}-Url'