From 7c4d039ca0e70df9f4f5e031235485e80b17e448 Mon Sep 17 00:00:00 2001
From: Burak Aktas <buraktas@gmail.com>
Date: Thu, 6 Jun 2024 14:44:47 +0300
Subject: [PATCH 1/2] refactor(events): Define limit on Rule Targets

---
 packages/aws-cdk-lib/aws-events/lib/rule.ts   |  2 ++
 .../aws-cdk-lib/aws-events/test/rule.test.ts  | 19 +++++++++++++++++++
 2 files changed, 21 insertions(+)

diff --git a/packages/aws-cdk-lib/aws-events/lib/rule.ts b/packages/aws-cdk-lib/aws-events/lib/rule.ts
index b96347e20ba2b..840eed9e5f866 100644
--- a/packages/aws-cdk-lib/aws-events/lib/rule.ts
+++ b/packages/aws-cdk-lib/aws-events/lib/rule.ts
@@ -320,6 +320,8 @@ export class Rule extends Resource implements IRule {
   private renderTargets() {
     if (this.targets.length === 0) {
       return undefined;
+    } else if (this.targets.length > 5) {
+      throw new Error('Event rule cannot have more than 5 targets.');
     }
 
     return this.targets;
diff --git a/packages/aws-cdk-lib/aws-events/test/rule.test.ts b/packages/aws-cdk-lib/aws-events/test/rule.test.ts
index 80f3c5cbe53d6..dbcf5ad9bd01c 100644
--- a/packages/aws-cdk-lib/aws-events/test/rule.test.ts
+++ b/packages/aws-cdk-lib/aws-events/test/rule.test.ts
@@ -72,6 +72,25 @@ describe('rule', () => {
     });
   });
 
+  test('rule cannot have more than 5 targets', () => {
+    const app = new cdk.App();
+    const stack = new cdk.Stack(app);
+    const resource = new Construct(stack, 'Resource');
+    const rule = new Rule(stack, 'MyRule', {
+      schedule: Schedule.rate(cdk.Duration.minutes(10)),
+      targets: [
+        new SomeTarget('T1', resource),
+        new SomeTarget('T2', resource),
+        new SomeTarget('T3', resource),
+        new SomeTarget('T4', resource),
+        new SomeTarget('T5', resource),
+        new SomeTarget('T6', resource),
+      ],
+    });
+
+    expect(() => app.synth()).toThrow(/Event rule cannot have more than 5 targets./);
+  });
+
   test('get rate as token', () => {
     const app = new cdk.App();
     const stack = new cdk.Stack(app, 'MyScheduledStack');

From ef3bd89baf6104780efe89919fe3091cb7fd4e25 Mon Sep 17 00:00:00 2001
From: Burak Aktas <buraktas@gmail.com>
Date: Thu, 6 Jun 2024 20:47:59 +0300
Subject: [PATCH 2/2] move target length check into validate method

---
 packages/aws-cdk-lib/aws-events/lib/rule.ts | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/packages/aws-cdk-lib/aws-events/lib/rule.ts b/packages/aws-cdk-lib/aws-events/lib/rule.ts
index 840eed9e5f866..bbac64b14e63a 100644
--- a/packages/aws-cdk-lib/aws-events/lib/rule.ts
+++ b/packages/aws-cdk-lib/aws-events/lib/rule.ts
@@ -314,14 +314,16 @@ export class Rule extends Resource implements IRule {
       errors.push('Either \'eventPattern\' or \'schedule\' must be defined');
     }
 
+    if (this.targets.length > 5) {
+      errors.push('Event rule cannot have more than 5 targets.');
+    }
+
     return errors;
   }
 
   private renderTargets() {
     if (this.targets.length === 0) {
       return undefined;
-    } else if (this.targets.length > 5) {
-      throw new Error('Event rule cannot have more than 5 targets.');
     }
 
     return this.targets;