From f533ba2d2c00c6c1a8d143aea4b29857a6ed018a Mon Sep 17 00:00:00 2001
From: go-to-k <24818752+go-to-k@users.noreply.github.com>
Date: Fri, 17 Nov 2023 15:04:02 +0900
Subject: [PATCH 1/3] chore(lambda): validate logLevel with JSON logFormat for
 advanced logging

---
 .../aws-cdk-lib/aws-lambda/lib/function.ts    |  4 ++
 .../aws-lambda/test/logging-config.test.ts    | 56 ++++++++++++++++++-
 2 files changed, 59 insertions(+), 1 deletion(-)

diff --git a/packages/aws-cdk-lib/aws-lambda/lib/function.ts b/packages/aws-cdk-lib/aws-lambda/lib/function.ts
index 5c64c7069f65e..cc461fa788607 100644
--- a/packages/aws-cdk-lib/aws-lambda/lib/function.ts
+++ b/packages/aws-cdk-lib/aws-lambda/lib/function.ts
@@ -1077,6 +1077,10 @@ export class Function extends FunctionBase {
    * function and undefined if not.
    */
   private getLoggingConfig(props: FunctionProps): CfnFunction.LoggingConfigProperty | undefined {
+    if ((props.applicationLogLevel || props.systemLogLevel) && props.logFormat !== LogFormat.JSON) {
+      throw new Error('ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON.');
+    }
+
     let loggingConfig: CfnFunction.LoggingConfigProperty;
     if (props.logFormat || props.logGroup) {
       loggingConfig = {
diff --git a/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts b/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts
index ad4c5dd2b956b..73405aa805b9f 100644
--- a/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts
+++ b/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts
@@ -133,6 +133,60 @@ describe('logging Config', () => {
           logGroupName: 'customLogGroup',
         }),
       });
-    }).toThrowError('CDK does not support setting logRetention and logGroup');
+    }).toThrow(/CDK does not support setting logRetention and logGroup/);
+  });
+
+  test('Throws when applicationLogLevel is specified with TEXT logFormat', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'stack');
+    expect(() => {
+      new lambda.Function(stack, 'Lambda', {
+        code: new lambda.InlineCode('foo'),
+        handler: 'index.handler',
+        runtime: lambda.Runtime.NODEJS_18_X,
+        logFormat: lambda.LogFormat.TEXT,
+        applicationLogLevel: lambda.ApplicationLogLevel.INFO,
+      });
+    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+  });
+
+  test('Throws when systemLogLevel is specified with TEXT logFormat', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'stack');
+    expect(() => {
+      new lambda.Function(stack, 'Lambda', {
+        code: new lambda.InlineCode('foo'),
+        handler: 'index.handler',
+        runtime: lambda.Runtime.NODEJS_18_X,
+        logFormat: lambda.LogFormat.TEXT,
+        systemLogLevel: lambda.SystemLogLevel.INFO,
+      });
+    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+  });
+
+  test('Throws when applicationLogLevel is specified if logFormat is undefined', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'stack');
+    expect(() => {
+      new lambda.Function(stack, 'Lambda', {
+        code: new lambda.InlineCode('foo'),
+        handler: 'index.handler',
+        runtime: lambda.Runtime.NODEJS_18_X,
+        applicationLogLevel: lambda.ApplicationLogLevel.INFO,
+      });
+    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+  });
+
+  test('Throws when systemLogLevel is specified if logFormat is undefined', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app, 'stack');
+    expect(() => {
+      new lambda.Function(stack, 'Lambda', {
+        code: new lambda.InlineCode('foo'),
+        handler: 'index.handler',
+        runtime: lambda.Runtime.NODEJS_18_X,
+        systemLogLevel: lambda.SystemLogLevel.INFO,
+      });
+    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
   });
 });

From 37d73baba15ce9e09c0ecd3908fa5ee3661e307d Mon Sep 17 00:00:00 2001
From: go-to-k <24818752+go-to-k@users.noreply.github.com>
Date: Sat, 18 Nov 2023 05:12:50 +0900
Subject: [PATCH 2/3] fix by the review

---
 packages/aws-cdk-lib/aws-lambda/README.md                 | 2 ++
 packages/aws-cdk-lib/aws-lambda/lib/function.ts           | 2 +-
 .../aws-cdk-lib/aws-lambda/test/logging-config.test.ts    | 8 ++++----
 3 files changed, 7 insertions(+), 5 deletions(-)

diff --git a/packages/aws-cdk-lib/aws-lambda/README.md b/packages/aws-cdk-lib/aws-lambda/README.md
index bf78d75090b26..79d8a5484ea1a 100644
--- a/packages/aws-cdk-lib/aws-lambda/README.md
+++ b/packages/aws-cdk-lib/aws-lambda/README.md
@@ -173,6 +173,8 @@ new lambda.Function(this, 'Lambda', {
 });
 ```
 
+To use `ApplicationLogLevel` and/or `SystemLogLevel` you must set `LogFormat` to `LogFormat.JSON`.
+
 ## Resource-based Policies
 
 AWS Lambda supports resource-based policies for controlling access to Lambda
diff --git a/packages/aws-cdk-lib/aws-lambda/lib/function.ts b/packages/aws-cdk-lib/aws-lambda/lib/function.ts
index cc461fa788607..cd0f60157cedd 100644
--- a/packages/aws-cdk-lib/aws-lambda/lib/function.ts
+++ b/packages/aws-cdk-lib/aws-lambda/lib/function.ts
@@ -1078,7 +1078,7 @@ export class Function extends FunctionBase {
    */
   private getLoggingConfig(props: FunctionProps): CfnFunction.LoggingConfigProperty | undefined {
     if ((props.applicationLogLevel || props.systemLogLevel) && props.logFormat !== LogFormat.JSON) {
-      throw new Error('ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON.');
+      throw new Error(`To use ApplicationLogLevel and/or SystemLogLevel you must set LogFormat to '${LogFormat.JSON}', got '${props.logFormat}'.`);
     }
 
     let loggingConfig: CfnFunction.LoggingConfigProperty;
diff --git a/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts b/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts
index 73405aa805b9f..c114405ed3827 100644
--- a/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts
+++ b/packages/aws-cdk-lib/aws-lambda/test/logging-config.test.ts
@@ -147,7 +147,7 @@ describe('logging Config', () => {
         logFormat: lambda.LogFormat.TEXT,
         applicationLogLevel: lambda.ApplicationLogLevel.INFO,
       });
-    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+    }).toThrow(/To use ApplicationLogLevel and\/or SystemLogLevel you must set LogFormat to 'JSON', got 'Text'./);
   });
 
   test('Throws when systemLogLevel is specified with TEXT logFormat', () => {
@@ -161,7 +161,7 @@ describe('logging Config', () => {
         logFormat: lambda.LogFormat.TEXT,
         systemLogLevel: lambda.SystemLogLevel.INFO,
       });
-    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+    }).toThrow(/To use ApplicationLogLevel and\/or SystemLogLevel you must set LogFormat to 'JSON', got 'Text'./);
   });
 
   test('Throws when applicationLogLevel is specified if logFormat is undefined', () => {
@@ -174,7 +174,7 @@ describe('logging Config', () => {
         runtime: lambda.Runtime.NODEJS_18_X,
         applicationLogLevel: lambda.ApplicationLogLevel.INFO,
       });
-    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+    }).toThrow(/To use ApplicationLogLevel and\/or SystemLogLevel you must set LogFormat to 'JSON', got 'undefined'./);
   });
 
   test('Throws when systemLogLevel is specified if logFormat is undefined', () => {
@@ -187,6 +187,6 @@ describe('logging Config', () => {
         runtime: lambda.Runtime.NODEJS_18_X,
         systemLogLevel: lambda.SystemLogLevel.INFO,
       });
-    }).toThrow(/ApplicationLogLevel and SystemLogLevel cannot be specified without LogFormat being set to JSON./);
+    }).toThrow(/To use ApplicationLogLevel and\/or SystemLogLevel you must set LogFormat to 'JSON', got 'undefined'./);
   });
 });

From 0e45f0512bcbf5e57443e5eeb831fecd7d2e44f0 Mon Sep 17 00:00:00 2001
From: go-to-k <24818752+go-to-k@users.noreply.github.com>
Date: Sat, 18 Nov 2023 05:13:28 +0900
Subject: [PATCH 3/3] change README

---
 packages/aws-cdk-lib/aws-lambda/README.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/aws-cdk-lib/aws-lambda/README.md b/packages/aws-cdk-lib/aws-lambda/README.md
index 79d8a5484ea1a..41ee3f6953b69 100644
--- a/packages/aws-cdk-lib/aws-lambda/README.md
+++ b/packages/aws-cdk-lib/aws-lambda/README.md
@@ -173,7 +173,7 @@ new lambda.Function(this, 'Lambda', {
 });
 ```
 
-To use `ApplicationLogLevel` and/or `SystemLogLevel` you must set `LogFormat` to `LogFormat.JSON`.
+To use `applicationLogLevel` and/or `systemLogLevel` you must set `logFormat` to `LogFormat.JSON`.
 
 ## Resource-based Policies