Create an application that references an external file in Application Composer

This example uses the AWS SAM CLI to create an application that references an external file for its state machine definition. You then load your project in Application Composer with your external file properly referenced.

Example

1. First, use the AWS SAM CLI sam init command to initialize a new application named demo. During the interactive flow, select the Multi-step workflow quick start template.

   $ sam init
   
   ...
   
   Which template source would you like to use?
           1 - AWS Quick Start Templates
           2 - Custom Template Location
   Choice: 1
   
   Choose an AWS Quick Start application template
           1 - Hello World Example
           2 - Multi-step workflow
           3 - Serverless API
           4 - Scheduled task
           ...
   Template: 2
   
   Which runtime would you like to use?
           1 - dotnet6
           2 - dotnetcore3.1
           ...
           15 - python3.7
           16 - python3.10
           17 - ruby2.7
   Runtime: 16
   
   Based on your selections, the only Package type available is Zip.
   We will proceed to selecting the Package type as Zip.
   
   Based on your selections, the only dependency manager available is pip.
   We will proceed copying the template using pip.
   
   Would you like to enable X-Ray tracing on the function(s) in your application?  [y/N]: ENTER
   
   Would you like to enable monitoring using CloudWatch Application Insights?
   For more info, please view https://docs.aws.amazon.com/AmazonCloudWatch/latest/monitoring/cloudwatch-application-insights.html [y/N]: ENTER
   
   Project name [sam-app]: demo
   
       -----------------------
       Generating application:
       -----------------------
       Name: demo
       Runtime: python3.10
       Architectures: x86_64
       Dependency Manager: pip
       Application Template: step-functions-sample-app
       Output Directory: .
       Configuration file: demo/samconfig.toml
       
       Next steps can be found in the README file at demo/README.md
   
   ...

   This application references an external file for the state machine definition.

   ...
   Resources:
     StockTradingStateMachine:
       Type: AWS::Serverless::StateMachine
       Properties:
         DefinitionUri: statemachine/stock_trader.asl.json
   ...

   The external file is located in the statemachine subdirectory of our application.

   demo
   ├── README.md
   ├── __init__.py
   ├── functions
   │   ├── __init__.py
   │   ├── stock_buyer
   │   ├── stock_checker
   │   └── stock_seller
   ├── samconfig.toml
   ├── statemachine
   │   └── stock_trader.asl.json
   ├── template.yaml
   └── tests

2. Next, load your application in Application Composer from the console. From the Application Composer home page, select Load a CloudFormation template.

3. Select our demo project folder and allow the prompt to view files. Select our template.yaml file and select Create. When prompted, select Save changes.

   

Application Composer automatically detects the external state machine definition file and loads it. Select our StockTradingStateMachine resource and choose Details to show the Resource properties panel. Here, you can see that Application Composer has automatically connected to our external state machine definition file.

Any changes made to the state machine definition file will be automatically reflected in Application Composer.