fix(s3): fail early with bad notification filters (#3397)

Avoid CF deploy time errors when specifying multiple prefixes or suffixes in notification filters.

Closes #3347
Possibly something to fix in v2.0 (#3398)

Author: jogold

packages/@aws-cdk/aws-s3/lib/notifications-resource/notifications-resource.ts

@@ -122,18 +122,28 @@ function renderFilters(filters?: NotificationKeyFilter[]): Filter | undefined {
   }
 
   const renderedRules = new Array<FilterRule>();
+  let hasPrefix = false;
+  let hasSuffix = false;
 
   for (const rule of filters) {
     if (!rule.suffix && !rule.prefix) {
       throw new Error('NotificationKeyFilter must specify `prefix` and/or `suffix`');
     }
 
     if (rule.suffix) {
+      if (hasSuffix) {
+        throw new Error('Cannot specify more than one suffix rule in a filter.');
+      }
       renderedRules.push({ Name: 'suffix', Value: rule.suffix });
+      hasSuffix = true;
     }
 
     if (rule.prefix) {
+      if (hasPrefix) {
+        throw new Error('Cannot specify more than one prefix rule in a filter.');
+      }
       renderedRules.push({ Name: 'prefix', Value: rule.prefix });
+      hasPrefix = true;
     }
   }
 

packages/@aws-cdk/aws-s3/test/test.notification.ts

@@ -21,4 +21,76 @@ export = {
 
     test.done();
   },
-};
+
+  'can specify prefix and suffix filter rules'(test: Test) {
+    const stack = new cdk.Stack();
+
+    const bucket = new s3.Bucket(stack, 'MyBucket');
+
+    bucket.addEventNotification(s3.EventType.OBJECT_CREATED, {
+      bind: () => ({
+        arn: 'ARN',
+        type: s3.BucketNotificationDestinationType.TOPIC
+      }),
+    }, { prefix: 'images/', suffix: '.png' });
+
+    expect(stack).to(haveResource('Custom::S3BucketNotifications', {
+      NotificationConfiguration: {
+        TopicConfigurations: [
+          {
+            Events: [
+              's3:ObjectCreated:*'
+            ],
+            Filter: {
+              Key: {
+                FilterRules: [
+                  {
+                    Name: 'suffix',
+                    Value: '.png'
+                  },
+                  {
+                    Name: 'prefix',
+                    Value: 'images/'
+                  }
+                ]
+              }
+            },
+            TopicArn: 'ARN'
+          }
+        ]
+      }
+    }));
+
+    test.done();
+  },
+
+  'throws with multiple prefix rules in a filter'(test: Test) {
+    const stack = new cdk.Stack();
+
+    const bucket = new s3.Bucket(stack, 'MyBucket');
+
+    test.throws(() => bucket.addEventNotification(s3.EventType.OBJECT_CREATED, {
+      bind: () => ({
+        arn: 'ARN',
+        type: s3.BucketNotificationDestinationType.TOPIC
+      }),
+    }, { prefix: 'images/'}, { prefix: 'archive/' }), /prefix rule/);
+
+    test.done();
+  },
+
+  'throws with multiple suffix rules in a filter'(test: Test) {
+    const stack = new cdk.Stack();
+
+    const bucket = new s3.Bucket(stack, 'MyBucket');
+
+    test.throws(() => bucket.addEventNotification(s3.EventType.OBJECT_CREATED, {
+      bind: () => ({
+        arn: 'ARN',
+        type: s3.BucketNotificationDestinationType.TOPIC
+      }),
+    }, { suffix: '.png'}, { suffix: '.zip' }), /suffix rule/);
+
+    test.done();
+  }
+};