fix(cloudfront): trim autogenerated cache policy name

packages/@aws-cdk/aws-cloudfront/lib/cache-policy.ts

@@ -129,9 +129,14 @@ export class CachePolicy extends Resource implements ICachePolicy {
       physicalName: props.cachePolicyName,
     });
 
-    const cachePolicyName = props.cachePolicyName ?? `${Names.uniqueId(this)}-${Stack.of(this).region}`;
+    const cachePolicyName = props.cachePolicyName ?? `${Names.uniqueId(this).slice(0, 110)}-${Stack.of(this).region}`;
+
     if (!Token.isUnresolved(cachePolicyName) && !cachePolicyName.match(/^[\w-]+$/i)) {
-      throw new Error(`'cachePolicyName' can only include '-', '_', and alphanumeric characters, got: '${props.cachePolicyName}'`);
+      throw new Error(`'cachePolicyName' can only include '-', '_', and alphanumeric characters, got: '${cachePolicyName}'`);
+    }
+
+    if (cachePolicyName.length > 128) {
+      throw new Error(`'cachePolicyName' cannot be longer than 128 characters, got: '${cachePolicyName.length}'`);
     }
 
     const minTtl = (props.minTtl ?? Duration.seconds(0)).toSeconds();

packages/@aws-cdk/aws-cloudfront/lib/distribution.ts

@@ -285,7 +285,7 @@ export class Distribution extends Resource implements IDistribution {
     // Comments have an undocumented limit of 128 characters
     const trimmedComment =
       props.comment && props.comment.length > 128
-        ? `${props.comment.substr(0, 128 - 3)}...`
+        ? `${props.comment.slice(0, 128 - 3)}...`
         : props.comment;
 
     const distribution = new CfnDistribution(this, 'Resource', {

packages/@aws-cdk/aws-cloudfront/test/cache-policy.test.ts

@@ -85,7 +85,12 @@ describe('CachePolicy', () => {
     });
   });
 
-  test('throws if given a cachePolicyName with invalid characters', () => {
+  test('throws on long policy names over 128 characters', () => {
+    const errorMessage = /'cachePolicyName' cannot be longer than 128 characters/;
+    expect(() => new CachePolicy(stack, 'CachePolicy1', { cachePolicyName: 'FooBarBaz'.repeat(15) })).toThrow(errorMessage);
+  });
+
+  test('throws if cachePolicyName contains invalid characters', () => {
     const errorMessage = /'cachePolicyName' can only include '-', '_', and alphanumeric characters/;
     expect(() => new CachePolicy(stack, 'CachePolicy1', { cachePolicyName: 'My Policy' })).toThrow(errorMessage);
     expect(() => new CachePolicy(stack, 'CachePolicy2', { cachePolicyName: 'MyPolicy!' })).toThrow(errorMessage);