Connect cards on Application Composer's visual canvas - AWS Application Composer
Connecting enhanced component cardsConnecting standard cards

Connect cards on Application Composer's visual canvas

Use this topic to understand how to connect cards in Application Composer. This section includes details on connecting enhanced component cards and standard component cards. It also provides a few examples that illustrate the different ways cards can be connected.

Connecting enhanced component cards

On enhanced component cards, ports visually identify where connections can be made.

  • A port on the right side of a card indicates an opportunity for the card to invoke another card.

  • A port on the left side of a card indicates an opportunity for the card to be invoked by another card.

Connect cards together by clicking on a the right port of one card and dragging it onto a left port on another card.

An API Gateway card being connected to a Lambda function.

When you create a connection, a message will display, letting you know if the connection was successfully made. Select the message to see what Application Composer changed to provision a connection. If the connection was unsuccessful, you can select Template view to manually update your infrastructure code to provision the connection.

  • When successful, click on the message to view the Change inspector. Here, you can see what Application Composer modified to provision your connection.

  • When unsuccessful, a message will display. You can select the Template view and manually update your infrastructure code to provision the connection.

Bringing up the Change Inspector from the bottom of the screen.

When you connect enhanced component cards together, Application Composer automatically creates the infrastructure code in your template to provision the event-driven relationship between your resources.

Connecting standard component cards (Standard IaC resource cards)

Standard IaC resource cards do not include ports to create connections with other resources. During card configuration, you specify event-driven relationships in the template of your application, Application Composer will automatically detect these connections and visualize them with a dotted line between your cards. The following is an example of a connection between a standard component card and an enhanced component card:

A standard component card connected to an enhanced component card.

The following example shows how a Lambda function can be connected with an Amazon API Gateway rest API:

AWSTemplateFormatVersion: '2010-09-09'
Resources:
  MyApi:
    Type: 'AWS::ApiGateway::RestApi'
    Properties:
      Name: MyApi

  ApiGatewayMethod:
    Type: 'AWS::ApiGateway::Method'
    Properties:
      HttpMethod: POST  # Specify the HTTP method you want to use (e.g., GET, POST, PUT, DELETE)
      ResourceId: !GetAtt MyApi.RootResourceId
      RestApiId: !Ref MyApi
      AuthorizationType: NONE
      Integration:
        Type: AWS_PROXY
        IntegrationHttpMethod: POST
        Uri: !Sub
          - arn:aws:apigateway:${AWS::Region}:lambda:path/2015-03-31/functions/${LambdaFunctionArn}/invocations
          - { LambdaFunctionArn: !GetAtt MyLambdaFunction.Arn }
      MethodResponses:
        - StatusCode: 200

  MyLambdaFunction:
    Type: 'AWS::Lambda::Function'
    Properties:
      Handler: index.handler
      Role: !GetAtt LambdaExecutionRole.Arn
      Runtime: nodejs14.x
      Code:
        S3Bucket: your-bucket-name
        S3Key: your-lambda-zip-file.zip

  LambdaExecutionRole:
    Type: 'AWS::IAM::Role'
    Properties:
      AssumeRolePolicyDocument:
        Version: '2012-10-17'
        Statement:
          - Effect: Allow
            Principal:
              Service: lambda.amazonaws.com
            Action: 'sts:AssumeRole'
      Policies:
        - PolicyName: LambdaExecutionPolicy
          PolicyDocument:
            Version: '2012-10-17'
            Statement:
              - Effect: Allow
                Action:
                  - 'logs:CreateLogGroup'
                  - 'logs:CreateLogStream'
                  - 'logs:PutLogEvents'
                Resource: 'arn:aws:logs:*:*:*'
              - Effect: Allow
                Action:
                  - 'lambda:InvokeFunction'
                Resource: !GetAtt MyLambdaFunction.Arn

In the above example, the snippet of code listed in ApiGatewayMethod: under Integration: specifies the event-driven relationship that connects the two cards.