Trigger AppSync subscription notification asynchronously

Question

I have some processing that takes place asynchronously and I would like to notify my AppSync subscribers when the processing finishes. How can I have my asynchronous Lambda function notify Apollo-AppSync client subscribers when the processing is complete?

I am only using Cognito User Pool authentication with my API.

Why is there no AppSync topic on re:Post?

I am only using Cognito User Pool authentication with my API.

Why is there no AppSync topic on re:Post?

Accepted Answer

IAM authentication is what I was looking for: https://docs.aws.amazon.com/appsync/latest/devguide/security-authz.html#aws-iam-authorization

Answer

You can leverage the concept of [Local Resolvers](https://docs.aws.amazon.com/appsync/latest/devguide/tutorial-local-resolvers.html) for your task.

Asynchronous Lambda can invoke mutation on a None datasource, which will cause mutation result (can be as simple as an echo of all input arguments) to be forwarded to all subscription clients.

You can review [How do I notify AWS AppSync subscribers of external database updates that aren't performed by client-side mutations?](https://aws.amazon.com/premiumsupport/knowledge-center/appsync-notify-subscribers-real-time/) for more details and step-by-step implementation guidelines.

Answer

What is the best practice for having my Lambda invoke a mutation? Right now my AppSync API is authorized via Cognito User Pools.

Trigger AppSync subscription notification asynchronously

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