Support AWS AppSync Events (Event APIs / channel namespaces)

[sid88in]

AWS AppSync Events (Event APIs) are serverless WebSocket pub/sub APIs — clients subscribe
to channels and publish events over WebSocket/HTTP without managing connections. Launched Oct
2024; CDK L2 constructs Feb 2025; data-source integrations for channel namespaces Apr 2025.

• https://aws.amazon.com/about-aws/whats-new/2024/10/aws-appsync-websocket-apis-web-mobile-experiences/
• https://aws.amazon.com/about-aws/whats-new/2025/04/aws-appsync-events-data-source-integrations-channel-namespaces

Current state (verified)

The plugin is built entirely around AWS::AppSync::GraphQLApi and its resolvers/data
sources. Event APIs use different top-level resources — AWS::AppSync::Api (with an
EventConfig) and AWS::AppSync::ChannelNamespace — which the plugin doesn't model at all.

Scope decision needed

This is a new product surface, not an increment on the GraphQL API. Options:

1. Out of scope — keep this plugin GraphQL-only; point users to the AppSync Events CDK L2
   constructs or a dedicated plugin for Event APIs.
2. In scope, separate config block — add a top-level appSyncEvents (or similar) that
   synthesizes AWS::AppSync::Api + AWS::AppSync::ChannelNamespace, with channel-namespace
   handlers (APPSYNC_JS) and the Apr-2025 data-source integrations (Lambda/DynamoDB/Aurora).

This is a large effort and a genuine direction question for the project — filing it as a
scoping discussion rather than a committed feature. Given AWS shipped CDK L2 constructs, there
is precedent/demand for IaC support, but it may belong in its own plugin.