fix: align lambda log group and propagate correlation ids on errors

Author: tukue

lib/cdk-app-stack.ts

@@ -113,7 +113,7 @@ export class CdkAppStack extends cdk.Stack {
     });
 
     const lambdaAppLogs = new logs.LogGroup(this, 'LambdaApplicationLogs', {
-      logGroupName: `/aws/lambda/${lambda_backend.functionName}-application`,
+      logGroupName: `/aws/lambda/${lambda_backend.functionName}`,
       encryptionKey,
       retention: logs.RetentionDays.ONE_MONTH,
       removalPolicy: RemovalPolicy.RETAIN,

lib/function.ts

@@ -42,12 +42,12 @@ export const handler = async (
   event: APIGatewayEvent,
   context: Context
 ): Promise<APIGatewayProxyResult> => {
-  try {
-    const correlationId =
-      event.headers?.['x-correlation-id'] ||
-      event.headers?.['X-Correlation-Id'] ||
-      context.awsRequestId;
+  const correlationId =
+    event.headers?.['x-correlation-id'] ||
+    event.headers?.['X-Correlation-Id'] ||
+    context.awsRequestId;
 
+  try {
     log('INFO', 'request-received', {
       awsRequestId: context.awsRequestId,
       correlationId,
@@ -81,6 +81,7 @@ export const handler = async (
       headers: {
         'Content-Type': 'application/json',
         'Access-Control-Allow-Origin': '*',
+        'x-correlation-id': correlationId,
       },
       body: JSON.stringify({ error: 'Internal Server Error' }),
     };