Add delete task functionality with API integration and tests

Author: mwarman

docs/InfrastructureGuide.md

@@ -527,6 +527,40 @@ const tableName = process.env.TASK_TABLE_NAME;
 - **DynamoDB**: Read-write access (GetItem, UpdateItem) to the Task table
 - **CloudWatch Logs**: Write access to its log group
 
+#### Delete Task Function
+
+**Resource Type**: AWS Lambda Function
+
+**Configuration**:
+
+- **Function Name**: `{app-name}-delete-task-{env}`
+- **Runtime**: Node.js 24.x
+- **Handler**: `handler` (bundled with esbuild)
+- **Memory**: 256 MB
+- **Timeout**: 10 seconds
+- **Log Format**: JSON (structured logging)
+- **Bundling**: Automatic TypeScript compilation with esbuild
+- **Environment Variables**:
+  - `TASKS_TABLE`: DynamoDB table name
+  - `ENABLE_LOGGING`: Logging enabled flag (from `CDK_APP_ENABLE_LOGGING`)
+  - `LOG_LEVEL`: Minimum log level (from `CDK_APP_LOGGING_LEVEL`)
+  - `LOG_FORMAT`: Log output format (from `CDK_APP_LOGGING_FORMAT`)
+
+**CloudWatch Logs**:
+
+- **Log Group**: `/aws/lambda/{app-name}-delete-task-{env}`
+- **Log Retention**:
+  - `prd`: 30 days
+  - Other environments: 7 days
+- **Removal Policy**:
+  - `prd`: `RETAIN` (logs preserved on stack deletion)
+  - Other environments: `DESTROY` (logs deleted on stack deletion)
+
+**IAM Permissions**:
+
+- **DynamoDB**: Read-write access (DeleteItem) to the Task table
+- **CloudWatch Logs**: Write access to its log group
+
 #### Lambda Starter API
 
 **Resource Type**: API Gateway REST API
@@ -586,6 +620,15 @@ const tableName = process.env.TASK_TABLE_NAME;
     - 404 Not Found: Task ID does not exist
     - 500 Internal Server Error: Failed to update task
 
+- **DELETE /tasks/{taskId}**: Delete an existing task
+  - Integration: Lambda proxy integration with Delete Task Function
+  - Path Parameter: `taskId` - The unique identifier of the task
+  - Response: No content on successful deletion
+  - Success Status: 204 No Content
+  - Error Responses:
+    - 404 Not Found: Task ID does not exist or path parameter is missing
+    - 500 Internal Server Error: Failed to delete task
+
 **Outputs**:
 
 - `ApiUrl`: The API Gateway endpoint URL (e.g., `https://abc123.execute-api.us-east-1.amazonaws.com/dev/`)
@@ -594,6 +637,7 @@ const tableName = process.env.TASK_TABLE_NAME;
 - `GetTaskFunctionArn`: The Get Task Lambda function ARN
 - `CreateTaskFunctionArn`: The Create Task Lambda function ARN
 - `UpdateTaskFunctionArn`: The Update Task Lambda function ARN
+- `DeleteTaskFunctionArn`: The Delete Task Lambda function ARN
 
 **Logging Configuration**:
 

infrastructure/README.md

@@ -297,6 +297,13 @@ npm run cdk destroy --all
   - Handler: Updates an existing task in DynamoDB
   - IAM Permissions: Read-write access to Task table (GetItem, UpdateItem)
 
+- **Delete Task Function** (`delete-task-{env}`)
+  - Runtime: Node.js 24.x
+  - Memory: 256 MB
+  - Timeout: 10 seconds
+  - Handler: Deletes an existing task from DynamoDB
+  - IAM Permissions: Read-write access to Task table (DeleteItem)
+
 **Common Lambda Configuration:**
 
 - Log Format: JSON (structured logging)
@@ -314,6 +321,7 @@ npm run cdk destroy --all
     - `GET /tasks/{taskId}` - Get a specific task
     - `POST /tasks` - Create a new task
     - `PUT /tasks/{taskId}` - Update an existing task
+    - `DELETE /tasks/{taskId}` - Delete an existing task
   - CORS: Enabled with preflight OPTIONS support
   - Throttling: Rate and burst limits configured
   - Stage: `{env}` (e.g., `dev`, `prd`)
@@ -326,6 +334,7 @@ npm run cdk destroy --all
 - `GetTaskFunctionArn`: The Get Task Lambda function ARN
 - `CreateTaskFunctionArn`: The Create Task Lambda function ARN
 - `UpdateTaskFunctionArn`: The Update Task Lambda function ARN
+- `DeleteTaskFunctionArn`: The Delete Task Lambda function ARN
 
 **Logging Configuration:**
 

infrastructure/stacks/lambda-stack.test.ts

@@ -87,6 +87,16 @@ describe('LambdaStack', () => {
       });
     });
 
+    it('should create a delete task Lambda function', () => {
+      template.hasResourceProperties('AWS::Lambda::Function', {
+        FunctionName: 'lambda-starter-delete-task-dev',
+        Runtime: 'nodejs24.x',
+        Handler: 'handler',
+        Timeout: 10,
+        MemorySize: 256,
+      });
+    });
+
     it('should configure Lambda environment variables', () => {
       template.hasResourceProperties('AWS::Lambda::Function', {
         Environment: {
@@ -138,6 +148,12 @@ describe('LambdaStack', () => {
       });
     });
 
+    it('should create a DELETE method on /tasks/{taskId}', () => {
+      template.hasResourceProperties('AWS::ApiGateway::Method', {
+        HttpMethod: 'DELETE',
+      });
+    });
+
     it('should integrate API Gateway with Lambda', () => {
       template.hasResourceProperties('AWS::ApiGateway::Method', {
         Integration: {
@@ -250,6 +266,14 @@ describe('LambdaStack', () => {
       });
     });
 
+    it('should export delete task function ARN', () => {
+      template.hasOutput('DeleteTaskFunctionArn', {
+        Export: {
+          Name: 'lambda-starter-delete-task-function-arn-dev',
+        },
+      });
+    });
+
     it('should grant Lambda read-write access to DynamoDB for update function', () => {
       template.hasResourceProperties('AWS::IAM::Policy', {
         PolicyDocument: {

infrastructure/stacks/lambda-stack.ts

@@ -71,6 +71,11 @@ export class LambdaStack extends cdk.Stack {
    */
   public readonly updateTaskFunction: NodejsFunction;
 
+  /**
+   * The delete task Lambda function.
+   */
+  public readonly deleteTaskFunction: NodejsFunction;
+
   constructor(scope: Construct, id: string, props: LambdaStackProps) {
     super(scope, id, props);
 
@@ -198,6 +203,37 @@ export class LambdaStack extends cdk.Stack {
     // Grant the Lambda function read and write access to the DynamoDB table
     props.taskTable.grantReadWriteData(this.updateTaskFunction);
 
+    // Create the delete task Lambda function
+    this.deleteTaskFunction = new NodejsFunction(this, 'DeleteTaskFunction', {
+      functionName: `${props.appName}-delete-task-${props.envName}`,
+      runtime: lambda.Runtime.NODEJS_24_X,
+      handler: 'handler',
+      entry: path.join(__dirname, '../../src/handlers/delete-task.ts'),
+      environment: {
+        TASKS_TABLE: props.taskTable.tableName,
+        ENABLE_LOGGING: props.enableLogging.toString(),
+        LOG_LEVEL: props.loggingLevel,
+        LOG_FORMAT: props.loggingFormat,
+      },
+      timeout: cdk.Duration.seconds(10),
+      memorySize: 256,
+      bundling: {
+        minify: true,
+        sourceMap: true,
+      },
+      loggingFormat: lambda.LoggingFormat.JSON,
+      applicationLogLevelV2: lambda.ApplicationLogLevel.INFO,
+      systemLogLevelV2: lambda.SystemLogLevel.INFO,
+      logGroup: new logs.LogGroup(this, 'DeleteTaskFunctionLogGroup', {
+        logGroupName: `/aws/lambda/${props.appName}-delete-task-${props.envName}`,
+        retention: props.envName === 'prd' ? logs.RetentionDays.ONE_MONTH : logs.RetentionDays.ONE_WEEK,
+        removalPolicy: props.envName === 'prd' ? cdk.RemovalPolicy.RETAIN : cdk.RemovalPolicy.DESTROY,
+      }),
+    });
+
+    // Grant the Lambda function read and write access to the DynamoDB table
+    props.taskTable.grantReadWriteData(this.deleteTaskFunction);
+
     // Create API Gateway REST API
     this.api = new apigateway.RestApi(this, 'LambdaStarterApi', {
       restApiName: `${props.appName}-api-${props.envName}`,
@@ -232,6 +268,9 @@ export class LambdaStack extends cdk.Stack {
     // Add PUT method to /tasks/{taskId}
     taskResource.addMethod('PUT', new apigateway.LambdaIntegration(this.updateTaskFunction));
 
+    // Add DELETE method to /tasks/{taskId}
+    taskResource.addMethod('DELETE', new apigateway.LambdaIntegration(this.deleteTaskFunction));
+
     // Output the API URL
     new cdk.CfnOutput(this, 'ApiUrl', {
       value: this.api.url,
@@ -273,5 +312,12 @@ export class LambdaStack extends cdk.Stack {
       description: 'ARN of the update task Lambda function',
       exportName: `${props.appName}-update-task-function-arn-${props.envName}`,
     });
+
+    // Output the delete task function ARN
+    new cdk.CfnOutput(this, 'DeleteTaskFunctionArn', {
+      value: this.deleteTaskFunction.functionArn,
+      description: 'ARN of the delete task Lambda function',
+      exportName: `${props.appName}-delete-task-function-arn-${props.envName}`,
+    });
   }
 }