fix(lambda): Validate Lambda "functionName" parameter (#17970)

Closes #13264

----

*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: Dzhuneyt

packages/@aws-cdk/aws-lambda/lib/function.ts

@@ -6,7 +6,7 @@ import * as kms from '@aws-cdk/aws-kms';
 import * as logs from '@aws-cdk/aws-logs';
 import * as sns from '@aws-cdk/aws-sns';
 import * as sqs from '@aws-cdk/aws-sqs';
-import { Annotations, ArnFormat, CfnResource, Duration, Fn, Lazy, Names, Stack } from '@aws-cdk/core';
+import { Annotations, ArnFormat, CfnResource, Duration, Fn, Lazy, Names, Stack, Token } from '@aws-cdk/core';
 import { Construct } from 'constructs';
 import { Architecture } from './architecture';
 import { Code, CodeConfig } from './code';
@@ -627,6 +627,15 @@ export class Function extends FunctionBase {
       physicalName: props.functionName,
     });
 
+    if (props.functionName && !Token.isUnresolved(props.functionName)) {
+      if (props.functionName.length > 64) {
+        throw new Error(`Function name can not be longer than 64 characters but has ${props.functionName.length} characters.`);
+      }
+      if (!/^[a-zA-Z0-9-_]+$/.test(props.functionName)) {
+        throw new Error(`Function name ${props.functionName} can contain only letters, numbers, hyphens, or underscores with no spaces.`);
+      }
+    }
+
     const managedPolicies = new Array<iam.IManagedPolicy>();
 
     // the arn is in the form of - arn:aws:iam::aws:policy/service-role/AWSLambdaBasicExecutionRole

packages/@aws-cdk/aws-lambda/test/function.test.ts

@@ -12,6 +12,7 @@ import * as sns from '@aws-cdk/aws-sns';
 import * as sqs from '@aws-cdk/aws-sqs';
 import { testDeprecated } from '@aws-cdk/cdk-build-tools';
 import * as cdk from '@aws-cdk/core';
+import { Intrinsic, Token } from '@aws-cdk/core';
 import * as constructs from 'constructs';
 import * as _ from 'lodash';
 import * as lambda from '../lib';
@@ -2404,6 +2405,45 @@ describe('function', () => {
     });
     expect(fn.architecture?.name).toEqual('arm64');
   });
+
+  test('Error when function name is longer than 64 chars', () => {
+    const stack = new cdk.Stack();
+    expect(() => new lambda.Function(stack, 'MyFunction', {
+      code: lambda.Code.fromInline('foo'),
+      runtime: lambda.Runtime.NODEJS_14_X,
+      handler: 'index.handler',
+      functionName: 'a'.repeat(65),
+    })).toThrow(/Function name can not be longer than 64 characters/);
+  });
+
+  test('Error when function name contains invalid characters', () => {
+    const stack = new cdk.Stack();
+    [' ', '\n', '\r', '[', ']', '<', '>', '$'].forEach(invalidChar => {
+      expect(() => {
+        new lambda.Function(stack, `foo${invalidChar}`, {
+          code: new lambda.InlineCode('foo'),
+          handler: 'index.handler',
+          runtime: lambda.Runtime.NODEJS_14_X,
+          functionName: `foo${invalidChar}`,
+        });
+      }).toThrow(/can contain only letters, numbers, hyphens, or underscores with no spaces./);
+    });
+  });
+
+  test('No error when function name is Tokenized and Unresolved', () => {
+    const stack = new cdk.Stack();
+    expect(() => {
+      const realFunctionName = 'a'.repeat(141);
+      const tokenizedFunctionName = Token.asString(new Intrinsic(realFunctionName));
+
+      new lambda.Function(stack, 'foo', {
+        code: new lambda.InlineCode('foo'),
+        handler: 'index.handler',
+        runtime: lambda.Runtime.NODEJS_14_X,
+        functionName: tokenizedFunctionName,
+      });
+    }).not.toThrow();
+  });
 });
 
 function newTestLambda(scope: constructs.Construct) {