feat: add support for notifications on existing sns topics

package.json

@@ -39,9 +39,6 @@
     "pinst": "^2.1.4",
     "prettier": "^2.2.1"
   },
-  "peerDependencies": {
-    "serverless": "^2.4.0"
-  },
   "engines": {
     "node": ">=8.10.0"
   },

src/index.js

@@ -296,6 +296,28 @@ class AlertsPlugin {
         } else {
           alertTopics[key] = topic;
         }
+
+        const subscriptions = (notifications || []).reduce((memo, n) => {
+          const nameSuffix = n.name || '';
+          const cfRef = `AwsAlerts${upperFirst(key)}${upperFirst(n.protocol)}${nameSuffix}Subscription`;
+
+          if (memo[cfRef]) {
+            throw new Error('Subscription with the same protocol already exists! Use the name property to uniquely identify it');
+          }
+
+          return Object.assign(memo, {
+            [cfRef]: {
+              Type: 'AWS::SNS::Subscription',
+              Properties: {
+                TopicArn: topic,
+                Protocol: n.protocol,
+                Endpoint: n.endpoint,
+              },
+            },
+          });
+        }, {});
+
+        this.addCfResources(subscriptions);
       } else {
         const cfRef = `AwsAlerts${
           customAlarmName ? upperFirst(customAlarmName) : ''

src/index.test.js

@@ -484,7 +484,7 @@ describe('#index', () => {
       });
     });
 
-    it('should create SNS topic with notificaitons', () => {
+    it('should create SNS topic with notifications', () => {
       const topicName = 'ok-topic';
       const plugin = pluginFactory({
         topics: {
@@ -528,6 +528,93 @@ describe('#index', () => {
       });
     });
 
+    it('should create SNS subscription for existing topic', () => {
+      const plugin = pluginFactory({
+        topics: {
+          ok: {
+            topic: {
+              Ref: 'AwsAlertsAlarm',
+            },
+            notifications: [
+              {
+                protocol: 'email',
+                endpoint: '[email protected]',
+              },
+            ],
+          },
+        },
+      });
+
+      const config = plugin.getConfig();
+      const topics = plugin.compileAlertTopics(config);
+
+      expect(topics).toEqual({
+        ok: {
+          Ref: `AwsAlertsAlarm`,
+        },
+      });
+
+      expect(
+        plugin.serverless.service.provider.compiledCloudFormationTemplate
+          .Resources
+      ).toEqual({
+        AwsAlertsOkEmailSubscription: {
+          Type: 'AWS::SNS::Subscription',
+          Properties: {
+            TopicArn: {
+              Ref: 'AwsAlertsAlarm',
+            },
+            Protocol: 'email',
+            Endpoint: '[email protected]',
+          },
+        },
+      });
+    });
+
+    it('should create SNS subscription for existing topic with a custom name suffix', () => {
+      const plugin = pluginFactory({
+        topics: {
+          ok: {
+            topic: {
+              Ref: 'AwsAlertsAlarm',
+            },
+            notifications: [
+              {
+                name: 'Test',
+                protocol: 'email',
+                endpoint: '[email protected]',
+              },
+            ],
+          },
+        },
+      });
+
+      const config = plugin.getConfig();
+      const topics = plugin.compileAlertTopics(config);
+
+      expect(topics).toEqual({
+        ok: {
+          Ref: `AwsAlertsAlarm`,
+        },
+      });
+
+      expect(
+        plugin.serverless.service.provider.compiledCloudFormationTemplate
+          .Resources
+      ).toEqual({
+        AwsAlertsOkEmailTestSubscription: {
+          Type: 'AWS::SNS::Subscription',
+          Properties: {
+            TopicArn: {
+              Ref: 'AwsAlertsAlarm',
+            },
+            Protocol: 'email',
+            Endpoint: '[email protected]',
+          },
+        },
+      });
+    });
+
     it('should create SNS topic with nested definitions', () => {
       const plugin = pluginFactory({
         topics: {