React Amplify GraphQL Subscription not triggered when data changed by Lambda

Question

I have a model configured like this:

type MyModel @model
    @auth(rules: [
        { allow: owner },
        { allow: private, provider: iam, operations: [read, update] }
    ])
{
    id: ID!
    someValue: Int
    otherValue: Int
}

and a subscription to the model:

const listener = API.graphql(graphqlOperation(onUpdateMyModel, {owner: user.username})).subscribe({
            next: (updatedModel) => {
                //do something
            }
        });

I also have a lambda that when triggered, updates otherValue on the model via a graphQL mutation. This however, does not trigger the subscription listener.

I've tested that the listener picks up when the user updates the model and this works perfectly fine so I know the subscription is working in general.

The API is configured with the cognito user pool as the default auth.

I must be missing something here but I can't work out what. How do I ensure my listener picks up changes made by the Lambda?

Answer 1

The reason this was not working had nothing to do with the fact that it was a lambda updating the record but everything to do with the custom mutation in which it was using to update the record.

All I needed to do was ensure all the fields were being returned by the mutation...this includes the auto generated createdAt and updatedAt .