Card connections in Application Composer
In AWS Application Composer, a connection between two cards is visually displayed by a line. These lines represent event-driven relationships within your application.
Topics
Connections between cards
How you connect cards together varies depending on the card type. Each enhanced card has at least one connector port. To connect them, you simply select one connector port and drag it to the port of another card, and Application Composer will connect the two resources or display a message stating this configuration isn’t supported.
As seen above, lines between enhanced component cards are solid. Conversely, standard IaC resource cards (also referred to as standard component cards) do not have connector ports. For these cards, you must specify these event-driven relationships in your application's template, and Application Composer will automatically detect their connections and visualize them with a dotted line between your cards.
To learn more, see the sections below.
Connections between enhanced component cards
In Application Composer, a connection between two enhanced component cards is visually displayed by a solid line. These lines represent event-driven relationships within your application.
To connect two cards, click on a port from one card and drag it onto a port on another card.
Note
Standard IaC resource cards do not have connector ports. For these cards, you must specify their event-driven relationships in your application's template, and Application Composer will automatically detect their connections and visualize them with a dotted line between your cards.
For more information, see Connect cards on Application Composer's visual canvas.
What enhanced component cards provision
Connections between two cards, visually indicated by a line, provision the following when necessary:
AWS Identity and Access Management (IAM) policies
Environment variables
Events
IAM policies
When a resource needs permission to invoke another resource, Application Composer provisions resource-based policies using AWS Serverless Application Model (AWS SAM) policy templates.
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To learn more about IAM permissions and policies, see Overview of access management: Permissions and policies in the IAM User Guide.
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To learn more about AWS SAM policy templates, see AWS SAM policy templates in the AWS Serverless Application Model Developer Guide.
Environment variables
Environment variables are temporary values that can be changed to affect the behavior of your resources. When necessary, Application Composer defines the infrastructure code to utilize environment variables between resources.
Events
Resources can invoke another resource through different types of events. When necessary, Application Composer defines the infrastructure code necessary for resources to interact through event types.
Connections to and from standard IaC resource cards
All AWS CloudFormation resources are available to use as standard IaC resource cards from the Resources palette. When you drag a standard IaC resource card onto the canvas, a standard IaC resource card becomes a standard component card, and this prompts Application Composer to create a starting template for your resource in your application.
For more information, see Standard cards in Application Composer.
