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fix(cli-internal): read DynamoDB event source properties from CFN template #14895

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7ea9a12
fix(cli-internal): read DynamoDB event source properties from CFN tem…
adrianjoshua-strutt May 18, 2026
90d40ae
fix(cli-internal): fix triggers[0].props bug in createDynamoTrigger
adrianjoshua-strutt May 18, 2026
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1 change: 1 addition & 0 deletions ...ion-apps/discussions/_snapshot.post.generate/amplify/function/activityTrigger/resource.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -51,6 +51,7 @@ export function applyEscapeHatches(backend: Backend, activity: Table) {
backend.activityTrigger.resources.lambda.addEventSource(
new DynamoEventSource(activity, {
startingPosition: StartingPosition.LATEST,
batchSize: 100,
})
);
activity.grantStreamRead(backend.activityTrigger.resources.lambda.role!);
Expand Down
47 changes: 35 additions & 12 deletions ...-apps/discussions/_snapshot.post.generate/amplify/function/recorduseractivity/resource.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -48,16 +48,39 @@ export function applyEscapeHatches(backend: Backend, activity: Table) {
'dynamodb:Delete*',
'dynamodb:PartiQLDelete'
);
for (const model of ['Topic', 'Post', 'Comment']) {
const table = backend.data.resources.tables[model];
backend.recorduseractivity.resources.lambda.addEventSource(
new DynamoEventSource(table, {
startingPosition: StartingPosition.LATEST,
})
);
table.grantStreamRead(backend.recorduseractivity.resources.lambda.role!);
table.grantTableListStreams(
backend.recorduseractivity.resources.lambda.role!
);
}
const tableTopic = backend.data.resources.tables['Topic'];
backend.recorduseractivity.resources.lambda.addEventSource(
new DynamoEventSource(tableTopic, {
startingPosition: StartingPosition.LATEST,
batchSize: 100,
})
);
tableTopic.grantStreamRead(backend.recorduseractivity.resources.lambda.role!);
tableTopic.grantTableListStreams(
backend.recorduseractivity.resources.lambda.role!
);
const tablePost = backend.data.resources.tables['Post'];
backend.recorduseractivity.resources.lambda.addEventSource(
new DynamoEventSource(tablePost, {
startingPosition: StartingPosition.LATEST,
batchSize: 100,
})
);
tablePost.grantStreamRead(backend.recorduseractivity.resources.lambda.role!);
tablePost.grantTableListStreams(
backend.recorduseractivity.resources.lambda.role!
);
const tableComment = backend.data.resources.tables['Comment'];
backend.recorduseractivity.resources.lambda.addEventSource(
new DynamoEventSource(tableComment, {
startingPosition: StartingPosition.LATEST,
batchSize: 100,
})
);
tableComment.grantStreamRead(
backend.recorduseractivity.resources.lambda.role!
);
tableComment.grantTableListStreams(
backend.recorduseractivity.resources.lambda.role!
);
}
265 changes: 255 additions & 10 deletions ...rc/__tests__/commands/gen2-migration/generate/amplify/function/function.generator.test.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -1069,16 +1069,14 @@ describe('FunctionGenerator', () => {

export function applyEscapeHatches(backend: Backend) {
backend.myFunc.resources.cfnResources.cfnFunction.functionName = \`myFunc-\${branchName}\`;
for (const model of ['Todo']) {
const table = backend.data.resources.tables[model];
backend.myFunc.resources.lambda.addEventSource(
new DynamoEventSource(table, {
startingPosition: StartingPosition.LATEST,
})
);
table.grantStreamRead(backend.myFunc.resources.lambda.role!);
table.grantTableListStreams(backend.myFunc.resources.lambda.role!);
}
const tableTodo = backend.data.resources.tables['Todo'];
backend.myFunc.resources.lambda.addEventSource(
new DynamoEventSource(tableTodo, {
startingPosition: StartingPosition.LATEST,
})
);
tableTodo.grantStreamRead(backend.myFunc.resources.lambda.role!);
tableTodo.grantTableListStreams(backend.myFunc.resources.lambda.role!);
}
"
`);
Expand Down Expand Up @@ -1264,4 +1262,251 @@ describe('FunctionGenerator', () => {
const generator = createFunctionGenerator({ gen1App, backendGenerator, packageJsonGenerator, outputDir });
await expect(generator.plan()).rejects.toThrow("unsupported runtime 'python3.9'");
});

it('renders single DynamoDB trigger with custom BatchSize and StartingPosition from CFN', async () => {
const gen1App = await createGen1App({
providers: { awscloudformation: { StackName: 'amplify-test-main-123456', Region: 'us-east-1' } },
function: {
myFunc: {
service: 'Lambda',
output: { Name: 'myFunc-main-abc', Arn: 'arn:aws:lambda:us-east-1:123:function:myFunc-main-abc' },
},
},
});
jest.spyOn(gen1App, 'resourceMetaOutput').mockReturnValue('myFunc-main-abc');
jest.spyOn(gen1App, 'json').mockReturnValue({
Resources: {
EventSourceMapping: {
Type: 'AWS::Lambda::EventSourceMapping',
Properties: {
EventSourceArn: {
'Fn::ImportValue': {
'Fn::Sub': '${api}:GetAtt:TodoTable:StreamArn',
},
},
FunctionName: { Ref: 'LambdaFunction' },
BatchSize: 50,
StartingPosition: 'TRIM_HORIZON',
},
},
},
});
jest.spyOn(gen1App, 'file').mockReturnValue('{}');
jest.spyOn(gen1App, 'fileExists').mockReturnValue(false);
jest.spyOn(gen1App.aws, 'fetchFunctionConfig').mockResolvedValue({
FunctionName: 'myFunc-main-abc',
Handler: 'index.handler',
Timeout: 3,
MemorySize: 128,
Runtime: 'nodejs18.x',
Environment: { Variables: {} },
});
jest.spyOn(gen1App.aws, 'fetchFunctionSchedule').mockResolvedValue(undefined);

const generator = createFunctionGenerator({ gen1App, backendGenerator, packageJsonGenerator, outputDir });
const ops = await generator.plan();
await ops[0].execute();

expect(writtenFile('resource.ts')).toMatchInlineSnapshot(`
"import { defineFunction } from '@aws-amplify/backend';
import { DynamoEventSource } from 'aws-cdk-lib/aws-lambda-event-sources';
import { StartingPosition } from 'aws-cdk-lib/aws-lambda';
import type { Backend } from '../../backend';

const branchName = process.env.AWS_BRANCH ?? 'sandbox';

export const myFunc = defineFunction({
entry: './index.js',
name: \`myFunc-\${branchName}\`,
timeoutSeconds: 3,
memoryMB: 128,
runtime: 18,
});

export function applyEscapeHatches(backend: Backend) {
backend.myFunc.resources.cfnResources.cfnFunction.functionName = \`myFunc-\${branchName}\`;
const tableTodo = backend.data.resources.tables['Todo'];
backend.myFunc.resources.lambda.addEventSource(
new DynamoEventSource(tableTodo, {
startingPosition: StartingPosition.TRIM_HORIZON,
batchSize: 50,
})
);
tableTodo.grantStreamRead(backend.myFunc.resources.lambda.role!);
tableTodo.grantTableListStreams(backend.myFunc.resources.lambda.role!);
}
"
`);
});

it('renders multiple DynamoDB triggers with DIFFERENT BatchSize/StartingPosition per model', async () => {
const gen1App = await createGen1App({
providers: { awscloudformation: { StackName: 'amplify-test-main-123456', Region: 'us-east-1' } },
function: {
myFunc: {
service: 'Lambda',
output: { Name: 'myFunc-main-abc', Arn: 'arn:aws:lambda:us-east-1:123:function:myFunc-main-abc' },
},
},
});
jest.spyOn(gen1App, 'resourceMetaOutput').mockReturnValue('myFunc-main-abc');
jest.spyOn(gen1App, 'json').mockReturnValue({
Resources: {
TodoEventSourceMapping: {
Type: 'AWS::Lambda::EventSourceMapping',
Properties: {
EventSourceArn: {
'Fn::ImportValue': {
'Fn::Sub': '${api}:GetAtt:TodoTable:StreamArn',
},
},
FunctionName: { Ref: 'LambdaFunction' },
BatchSize: 10,
StartingPosition: 'TRIM_HORIZON',
},
},
PostEventSourceMapping: {
Type: 'AWS::Lambda::EventSourceMapping',
Properties: {
EventSourceArn: {
'Fn::ImportValue': {
'Fn::Sub': '${api}:GetAtt:PostTable:StreamArn',
},
},
FunctionName: { Ref: 'LambdaFunction' },
BatchSize: 100,
StartingPosition: 'LATEST',
},
},
},
});
jest.spyOn(gen1App, 'file').mockReturnValue('{}');
jest.spyOn(gen1App, 'fileExists').mockReturnValue(false);
jest.spyOn(gen1App.aws, 'fetchFunctionConfig').mockResolvedValue({
FunctionName: 'myFunc-main-abc',
Handler: 'index.handler',
Timeout: 3,
MemorySize: 128,
Runtime: 'nodejs18.x',
Environment: { Variables: {} },
});
jest.spyOn(gen1App.aws, 'fetchFunctionSchedule').mockResolvedValue(undefined);

const generator = createFunctionGenerator({ gen1App, backendGenerator, packageJsonGenerator, outputDir });
const ops = await generator.plan();
await ops[0].execute();

expect(writtenFile('resource.ts')).toMatchInlineSnapshot(`
"import { defineFunction } from '@aws-amplify/backend';
import { DynamoEventSource } from 'aws-cdk-lib/aws-lambda-event-sources';
import { StartingPosition } from 'aws-cdk-lib/aws-lambda';
import type { Backend } from '../../backend';

const branchName = process.env.AWS_BRANCH ?? 'sandbox';

export const myFunc = defineFunction({
entry: './index.js',
name: \`myFunc-\${branchName}\`,
timeoutSeconds: 3,
memoryMB: 128,
runtime: 18,
});

export function applyEscapeHatches(backend: Backend) {
backend.myFunc.resources.cfnResources.cfnFunction.functionName = \`myFunc-\${branchName}\`;
const tableTodo = backend.data.resources.tables['Todo'];
backend.myFunc.resources.lambda.addEventSource(
new DynamoEventSource(tableTodo, {
startingPosition: StartingPosition.TRIM_HORIZON,
batchSize: 10,
})
);
tableTodo.grantStreamRead(backend.myFunc.resources.lambda.role!);
tableTodo.grantTableListStreams(backend.myFunc.resources.lambda.role!);
const tablePost = backend.data.resources.tables['Post'];
backend.myFunc.resources.lambda.addEventSource(
new DynamoEventSource(tablePost, {
startingPosition: StartingPosition.LATEST,
batchSize: 100,
})
);
tablePost.grantStreamRead(backend.myFunc.resources.lambda.role!);
tablePost.grantTableListStreams(backend.myFunc.resources.lambda.role!);
}
"
`);
});

it('falls back to StartingPosition LATEST when not specified in CFN template', async () => {
const gen1App = await createGen1App({
providers: { awscloudformation: { StackName: 'amplify-test-main-123456', Region: 'us-east-1' } },
function: {
myFunc: {
service: 'Lambda',
output: { Name: 'myFunc-main-abc', Arn: 'arn:aws:lambda:us-east-1:123:function:myFunc-main-abc' },
},
},
});
jest.spyOn(gen1App, 'resourceMetaOutput').mockReturnValue('myFunc-main-abc');
jest.spyOn(gen1App, 'json').mockReturnValue({
Resources: {
EventSourceMapping: {
Type: 'AWS::Lambda::EventSourceMapping',
Properties: {
EventSourceArn: {
'Fn::ImportValue': {
'Fn::Sub': '${api}:GetAtt:TodoTable:StreamArn',
},
},
FunctionName: { Ref: 'LambdaFunction' },
},
},
},
});
jest.spyOn(gen1App, 'file').mockReturnValue('{}');
jest.spyOn(gen1App, 'fileExists').mockReturnValue(false);
jest.spyOn(gen1App.aws, 'fetchFunctionConfig').mockResolvedValue({
FunctionName: 'myFunc-main-abc',
Handler: 'index.handler',
Timeout: 3,
MemorySize: 128,
Runtime: 'nodejs18.x',
Environment: { Variables: {} },
});
jest.spyOn(gen1App.aws, 'fetchFunctionSchedule').mockResolvedValue(undefined);

const generator = createFunctionGenerator({ gen1App, backendGenerator, packageJsonGenerator, outputDir });
const ops = await generator.plan();
await ops[0].execute();

expect(writtenFile('resource.ts')).toMatchInlineSnapshot(`
"import { defineFunction } from '@aws-amplify/backend';
import { DynamoEventSource } from 'aws-cdk-lib/aws-lambda-event-sources';
import { StartingPosition } from 'aws-cdk-lib/aws-lambda';
import type { Backend } from '../../backend';

const branchName = process.env.AWS_BRANCH ?? 'sandbox';

export const myFunc = defineFunction({
entry: './index.js',
name: \`myFunc-\${branchName}\`,
timeoutSeconds: 3,
memoryMB: 128,
runtime: 18,
});

export function applyEscapeHatches(backend: Backend) {
backend.myFunc.resources.cfnResources.cfnFunction.functionName = \`myFunc-\${branchName}\`;
const tableTodo = backend.data.resources.tables['Todo'];
backend.myFunc.resources.lambda.addEventSource(
new DynamoEventSource(tableTodo, {
startingPosition: StartingPosition.LATEST,
})
);
tableTodo.grantStreamRead(backend.myFunc.resources.lambda.role!);
tableTodo.grantTableListStreams(backend.myFunc.resources.lambda.role!);
}
"
`);
});
});
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