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fix(cli): cdk watch for Lambdas with Advanced Logging Controls do not stream logs to the terminal (#29451)
### Issue Closes #29448 ### Reason for this change After the release of Advanced Logging Controls for Lambda (see https://aws.amazon.com/blogs/compute/introducing-advanced-logging-controls-for-aws-lambda-functions/) I've decided to move all the logs of my multi-stack deployment to a single unified Log Group per deployed tenant. It goes likes this: The main stack creates the LogGroup like `/aws/lambda/{tenant}`; The secondary stacks refers to the LogGroup using `LogGroup.fromLogGroupArn(...)`; Then I discovered that running cdk watch on the main stack I can see the cloudwatch logs on my terminal while on the secondary stacks it does not; I found at that the cloudwatch log group resolver for the logs basically just assumes the log group is `/aws/lambda/{physicalId}` https://github.com/aws/aws-cdk/blob/main/packages/aws-cdk/lib/api/logs/find-cloudwatch-logs.ts#L114 ### Description of changes Use the Template JSON to resolve the `LoggingConfig.LogGroupName` of the Lambda Function; ### Description of how you validated changes I've replace the node_modules/aws-cdk of my project with the one built from this PR and I was able to see the logs of my lambda that has custom LogConfig, as you can see it is grabbing the logs of `/aws/lambda/dev` cloudwatch logs ![2024-03-13T10-46-48](https://github.com/aws/aws-cdk/assets/980905/d12113f6-67b6-4a54-96cf-66df6138d7f7) ### Checklist - [x] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)
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3 files changed

Lines changed: 117 additions & 33 deletions

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‎packages/aws-cdk/lib/api/evaluate-cloudformation-template.ts‎

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@@ -314,6 +314,10 @@ export class EvaluateCloudFormationTemplate {
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return cfnExpression;
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}
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public getResourceProperty(logicalId: string, propertyName: string): any {
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return this.template.Resources?.[logicalId]?.Properties?.[propertyName];
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}
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private references(logicalId: string, templateElement: any): boolean {
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if (typeof templateElement === 'string') {
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return logicalId === templateElement;

‎packages/aws-cdk/lib/api/logs/find-cloudwatch-logs.ts‎

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@@ -1,22 +1,12 @@
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import * as cxapi from '@aws-cdk/cx-api';
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import { CloudFormation } from 'aws-sdk';
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import { Mode, SdkProvider, ISDK } from '../aws-auth';
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import { ISDK, Mode, SdkProvider } from '../aws-auth';
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import { Deployments } from '../deployments';
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import { EvaluateCloudFormationTemplate, LazyListStackResources } from '../evaluate-cloudformation-template';
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// resource types that have associated CloudWatch Log Groups that should _not_ be monitored
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const IGNORE_LOGS_RESOURCE_TYPES = ['AWS::EC2::FlowLog', 'AWS::CloudTrail::Trail', 'AWS::CodeBuild::Project'];
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// Resource types that will create a CloudWatch log group with a specific name if one is not provided.
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// The keys are CFN resource types, and the values are the name of the physical name property of that resource
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// and the service name that is used in the automatically created CloudWatch log group.
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const RESOURCE_TYPES_WITH_IMPLICIT_LOGS: { [cfnResourceType: string]: { [key: string]: string } } = {
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'AWS::Lambda::Function': {
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PhysicalNamePropertyName: 'FunctionName',
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LogGroupServiceName: 'lambda',
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},
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};
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/**
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* Configuration needed to monitor CloudWatch Log Groups
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* found in a given CloudFormation Stack
@@ -84,38 +74,68 @@ function isReferencedFromIgnoredResource(
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logGroupResource: CloudFormation.StackResourceSummary,
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evaluateCfnTemplate: EvaluateCloudFormationTemplate,
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): boolean {
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let foundReference = false;
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const resourcesReferencingLogGroup = evaluateCfnTemplate.findReferencesTo(logGroupResource.LogicalResourceId);
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for (const reference of resourcesReferencingLogGroup) {
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if (IGNORE_LOGS_RESOURCE_TYPES.includes(reference.Type)) {
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foundReference = true;
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}
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}
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return foundReference;
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return resourcesReferencingLogGroup.some(reference => {
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return IGNORE_LOGS_RESOURCE_TYPES.includes(reference.Type);
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});
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}
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type CloudWatchLogsResolver = (
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resource: CloudFormation.StackResourceSummary,
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evaluateCfnTemplate: EvaluateCloudFormationTemplate
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) => string | undefined;
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const cloudWatchLogsResolvers: Record<string, CloudWatchLogsResolver> = {
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'AWS::Logs::LogGroup': (resource, evaluateCfnTemplate) => {
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if (isReferencedFromIgnoredResource(resource, evaluateCfnTemplate)) {
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return undefined;
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}
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return resource.PhysicalResourceId?.toString();
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},
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// Resource types that will create a CloudWatch log group with a specific name if one is not provided.
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// The keys are CFN resource types, and the values are the name of the physical name property of that resource
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// and the service name that is used in the automatically created CloudWatch log group.
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'AWS::Lambda::Function': (resource, evaluateCfnTemplate) => {
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const loggingConfig = evaluateCfnTemplate.getResourceProperty(resource.LogicalResourceId, 'LoggingConfig');
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if (loggingConfig?.LogGroup) {
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// if LogGroup is a string then use it as the LogGroupName as it is referred by LogGroup.fromLogGroupArn in CDK
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if (typeof loggingConfig.LogGroup === 'string') {
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return loggingConfig.LogGroup;
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}
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// if { Ref: '...' } is used then try to resolve the LogGroupName from the referenced resource in the template
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if (typeof loggingConfig.LogGroup === 'object') {
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if (loggingConfig.LogGroup.Ref) {
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return evaluateCfnTemplate.getResourceProperty(loggingConfig.LogGroup.Ref, 'LogGroupName');
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}
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}
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}
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return `/aws/lambda/${resource.PhysicalResourceId}`;
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},
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};
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/**
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* Find all CloudWatch Log Groups in the deployed template.
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* This will find both explicitely created Log Groups (excluding those associated with ignored resources)
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* as well as Log Groups created implicitely (i.e. Lambda Functions)
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* This will find both explicitly created Log Groups (excluding those associated with ignored resources)
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* and Log Groups created implicitly (i.e. Lambda Functions)
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*/
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function findAllLogGroupNames(
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stackResources: CloudFormation.StackResourceSummary[],
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evaluateCfnTemplate: EvaluateCloudFormationTemplate,
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): string[] {
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return stackResources.reduce((logGroupNames: string[], resource) => {
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let logGroupName;
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if (resource.ResourceType === 'AWS::Logs::LogGroup') {
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if (!isReferencedFromIgnoredResource(resource, evaluateCfnTemplate)) {
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logGroupName = resource.PhysicalResourceId;
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const logGroupNames: string[] = [];
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for (const resource of stackResources) {
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const logGroupResolver = cloudWatchLogsResolvers[resource.ResourceType];
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if (logGroupResolver) {
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const logGroupName = logGroupResolver(resource, evaluateCfnTemplate);
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if (logGroupName) {
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logGroupNames.push(logGroupName);
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}
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} else if (RESOURCE_TYPES_WITH_IMPLICIT_LOGS[resource.ResourceType]) {
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const servicePart = RESOURCE_TYPES_WITH_IMPLICIT_LOGS[resource.ResourceType].LogGroupServiceName;
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logGroupName = `/aws/${servicePart}/${resource.PhysicalResourceId}`;
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}
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if (logGroupName) {
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logGroupNames.push(logGroupName);
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}
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return logGroupNames;
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}, []);
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}
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return logGroupNames;
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}

‎packages/aws-cdk/test/api/logs/find-cloudwatch-logs.test.ts‎

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@@ -39,6 +39,66 @@ test('add log groups from lambda function', async () => {
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expect(result.logGroupNames).toEqual(['/aws/lambda/my-function']);
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});
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test('add log groups from lambda function when using custom LoggingConfig', async () => {
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// GIVEN
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const cdkStackArtifact = cdkStackArtifactOf({
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template: {
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Resources: {
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Func: {
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Type: 'AWS::Lambda::Function',
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Properties: {
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FunctionName: 'my-function',
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LoggingConfig: {
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LogGroup: '/this/custom/my-custom-log-group',
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},
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},
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},
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},
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},
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});
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pushStackResourceSummaries(stackSummaryOf('Func', 'AWS::Lambda::Function', 'my-function'));
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// WHEN
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const result = await findCloudWatchLogGroups(logsMockSdkProvider.mockSdkProvider, cdkStackArtifact);
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// THEN
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expect(result.logGroupNames).toEqual(['/this/custom/my-custom-log-group']);
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});
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test('add log groups from lambda function when using custom LoggingConfig using Ref', async () => {
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// GIVEN
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const cdkStackArtifact = cdkStackArtifactOf({
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template: {
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Resources: {
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MyCustomLogGroupLogicalId: {
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Type: 'AWS::Logs::LogGroup',
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Properties: {
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LogGroupName: '/this/custom/my-custom-log-group',
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},
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},
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Func: {
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Type: 'AWS::Lambda::Function',
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Properties: {
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FunctionName: 'my-function',
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LoggingConfig: {
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LogGroup: {
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Ref: 'MyCustomLogGroupLogicalId',
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},
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},
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},
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},
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},
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},
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});
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pushStackResourceSummaries(stackSummaryOf('Func', 'AWS::Lambda::Function', 'my-function'));
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// WHEN
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const result = await findCloudWatchLogGroups(logsMockSdkProvider.mockSdkProvider, cdkStackArtifact);
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// THEN
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expect(result.logGroupNames).toEqual(['/this/custom/my-custom-log-group']);
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});
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test('add log groups from lambda function without physical name', async () => {
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// GIVEN
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const cdkStackArtifact = cdkStackArtifactOf({

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