Merge pull request #307 from getlift/fix-queues-construct-alarm-exten…

…sion

Fix queues construct alarm extension

docs/queue.md

@@ -424,6 +424,8 @@ constructs:
 | dlq           	| AWS::SQS::Queue         	| [Link](https://docs.aws.amazon.com/AWSCloudFormation/latest/UserGuide/aws-resource-sqs-queue.html)        	|
 | alarm         	| AWS::CloudWatch::Alarm  	| [Link](https://docs.aws.amazon.com/fr_fr/AWSCloudFormation/latest/UserGuide/aws-properties-cw-alarm.html) 	|
 
+> ⚠️  The `alarm` extension key is only available if an alarm email destination has been configured on the construct.
+
 ### More options
 
 Feel like a common extension pattern should be implemented as part of the construct configuration? [Open a GitHub issue](https://github.com/getlift/lift/issues/new).

src/constructs/aws/Queue.ts

@@ -2,6 +2,7 @@ import { Key } from "aws-cdk-lib/aws-kms";
 import type { CfnQueue } from "aws-cdk-lib/aws-sqs";
 import { Queue as CdkQueue, QueueEncryption } from "aws-cdk-lib/aws-sqs";
 import type { FromSchema } from "json-schema-to-ts";
+import type { CfnAlarm } from "aws-cdk-lib/aws-cloudwatch";
 import { Alarm, ComparisonOperator, Metric } from "aws-cdk-lib/aws-cloudwatch";
 import { Subscription, SubscriptionProtocol, Topic } from "aws-cdk-lib/aws-sns";
 import type { AlarmActionConfig } from "aws-cdk-lib/aws-cloudwatch/lib/alarm-action";
@@ -117,6 +118,7 @@ export class Queue extends AwsConstruct {
 
     private readonly queue: CdkQueue;
     private readonly dlq: CdkQueue;
+    private readonly alarm?: Alarm;
     private readonly queueArnOutput: CfnOutput;
     private readonly queueUrlOutput: CfnOutput;
     private readonly dlqUrlOutput: CfnOutput;
@@ -218,7 +220,7 @@ export class Queue extends AwsConstruct {
                 endpoint: alarmEmail,
             });
 
-            const alarm = new Alarm(this, "Alarm", {
+            this.alarm = new Alarm(this, "Alarm", {
                 alarmName: `${this.provider.stackName}-${id}-dlq-alarm`,
                 alarmDescription: "Alert triggered when there are failed jobs in the dead letter queue.",
                 metric: new Metric({
@@ -235,7 +237,7 @@ export class Queue extends AwsConstruct {
                 threshold: 0,
                 comparisonOperator: ComparisonOperator.GREATER_THAN_THRESHOLD,
             });
-            alarm.addAlarmAction({
+            this.alarm.addAlarmAction({
                 bind(): AlarmActionConfig {
                     return { alarmActionArn: alarmTopic.topicArn };
                 },
@@ -279,11 +281,16 @@ export class Queue extends AwsConstruct {
     }
 
     extend(): Record<string, CfnResource> {
-        return {
+        const extensions = {
             queue: this.queue.node.defaultChild as CfnQueue,
             dlq: this.dlq.node.defaultChild as CfnQueue,
-            alarm: this.dlq.node.defaultChild as CfnQueue,
         };
+
+        if (this.alarm !== undefined) {
+            Object.assign(extensions, { alarm: this.alarm.node.defaultChild as CfnAlarm });
+        }
+
+        return extensions;
     }
 
     private getMaximumBatchingWindow(): number {

test/unit/queues.test.ts

@@ -620,4 +620,58 @@ describe("queues", () => {
             MaximumMessageSize: 1024,
         });
     });
+
+    it("allows overriding alarm properties", async () => {
+        const { cfTemplate, computeLogicalId } = await runServerless({
+            fixture: "queues",
+            configExt: merge({}, pluginConfigExt, {
+                constructs: {
+                    emails: {
+                        alarm: "[email protected]",
+                        extensions: {
+                            alarm: {
+                                Properties: {
+                                    AlarmActions: ["arn:aws:sns:region:account-id:sns-topic-name"],
+                                },
+                            },
+                        },
+                    },
+                },
+            }),
+            command: "package",
+        });
+        expect(cfTemplate.Resources[computeLogicalId("emails", "Alarm")].Properties).toMatchObject({
+            AlarmActions: ["arn:aws:sns:region:account-id:sns-topic-name"],
+        });
+    });
+
+    it("should throw if overriding alarm properties while no alarm is configured", async () => {
+        expect.assertions(2);
+
+        try {
+            await runServerless({
+                fixture: "queues",
+                configExt: merge({}, pluginConfigExt, {
+                    constructs: {
+                        emails: {
+                            extensions: {
+                                alarm: {
+                                    Properties: {
+                                        AlarmActions: ["arn:aws:sns:region:account-id:sns-topic-name"],
+                                    },
+                                },
+                            },
+                        },
+                    },
+                }),
+                command: "package",
+            });
+        } catch (error) {
+            expect(error).toBeInstanceOf(ServerlessError);
+            expect(error).toHaveProperty(
+                "message",
+                "There is no extension 'alarm' available on this construct. Available extensions are: queue, dlq."
+            );
+        }
+    });
 });