Change data source for resolver that extends Amplify-generated one

[jk171505]

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api

Amplify CLI Version
7.6.8

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Is this possible to change data source for new resolver that extends Amplify-generated one in new version of graphQL transformer (V2)?

[lazpavel]

Hi @jk171505, you should be able to achieve what you need by using CDK to define custom VTL resolvers as described here: https://docs.amplify.aws/cli/graphql/custom-business-logic/#vtl-resolver.

Please let us know if you still have any issues

[jk171505]

@lazpavel where do I define the exact slot for which I want to change the data source?

[jk171505]

Can I accomplish the same by defining the data source for specific slot in CustomResources.json?

[lazpavel]

I see, the link above will allow you to create and configure a custom resolver and not to update a different data source for a slot on an extended resolver.

For that you could use the documented way to extend a resolver (e.g: Mutation.createModelB.postAuth.2.req.vtl) and then use amplify override api and update the datasource for the specific appsyncFunction as below:

import { AmplifyApiGraphQlResourceStackTemplate } from '@aws-amplify/cli-extensibility-helper';

export function override(resources: AmplifyApiGraphQlResourceStackTemplate) { 
resources.models["**ModelB**"].appsyncFunctions["Mutationcreate**ModelB**postAuth1FunctionMutationcreate**ModelB**postAuth1Function.AppSyncFunction"].dataSourceName = "**ModelATable**";
}

[jk171505]

Thanks! That's exactly what I needed.

[Dennis-Dekker]

@lazpavel Is there a difference between the replacement of **ModelB** and **ModelATable** in your example? I'm confused by this, so if model A is named "Item" should **ModelATable** be "Item" or "ItemTable"?

[jk171505]

@Dennis-Dekker you are basically changing the dataSource for ModelB to ModelA. You should also add the suffix 'Table', so it should be:

resources.models["Item"].appsyncFunctions["MutationcreateItempostAuth1FunctionMutationcreateItempostAuth1Function.AppSyncFunction"].dataSourceName = "SomeOtherItemTable";

[ggorge-etiqa]

This is my override.ts:

import { AmplifyApiGraphQlResourceStackTemplate, AmplifyProjectInfo } from '@aws-amplify/cli-extensibility-helper';

export function override(resources: AmplifyApiGraphQlResourceStackTemplate, amplifyProjectInfo: AmplifyProjectInfo) {
    const model = resources.models["User"];
    model.appsyncFunctions["MutationcreateUserpreUpdate0Function.AppSyncFunction"].dataSourceName = "UniqueUsernameCheckLambdaDataSource";
}

On amplify push I' m getting this error:

Cannot set properties of undefined (setting 'dataSourceName')

Amplify version is 12.3.0.

Is what explained in this issue still valid?

[BradVidler]

@ggorge-etiqa Did you ever solve this? I'm facing the same issue.

[rob-lucky]

This is my override.ts:

import { AmplifyApiGraphQlResourceStackTemplate, AmplifyProjectInfo } from '@aws-amplify/cli-extensibility-helper';

export function override(resources: AmplifyApiGraphQlResourceStackTemplate, amplifyProjectInfo: AmplifyProjectInfo) {
    const model = resources.models["User"];
    model.appsyncFunctions["MutationcreateUserpreUpdate0Function.AppSyncFunction"].dataSourceName = "UniqueUsernameCheckLambdaDataSource";
}

On amplify push I' m getting this error:

Cannot set properties of undefined (setting 'dataSourceName')

Amplify version is 12.3.0.

Is what explained in this issue still valid?

Yes, this is still a valid solution with amplify cli v 12.11.1

For the function name you can also take a look into your build folder, where you can also find the generated resolvers. Here you can also find the CloudFormation stacks. Find the stack for your origin model. Find your function. The function should have this syntax: FunctionNameAppSyncFunctionRandomString.

You need the FunctionName part und use it in override.ts:
model.appsyncFunctions["FunctionName.AppSyncFunction"].dataSourceName = "SomeOtherItemTable";