fix(enabler): Add unregistration method to Node.js enabler (#1214)

Signed-off-by: at670475 <andrea.tabone@broadcom.com>

Author: taban03

onboarding-enabler-nodejs-sample-app/src/index.js

@@ -20,14 +20,15 @@ const args = {
     // The APIML stores such certificates in files with `-ebcdic` suffix
 };
 
+const app = express();
+let httpsServer;
 /**
  * Registers the service to the APIML Discovery service
  */
 /**
  * Starts the REST API service as an HTTPS server
  */
 function startHttpsService() {
-    const app = express();
 
     // Index page with a link to the REST API endpoint:
     app.get("/", (req, res) =>
@@ -49,15 +50,43 @@ function startHttpsService() {
     app.get("/api/v1/status", (req, res) => res.json({ status: "UP" }));
 
     // Static resources (contains Swagger JSON document with API documentation):
-    app.use(express.static("static"));
+    app.use(express.static("src/static"));
 
     // Start HTTPS server and register to Discovery Service:
     tlsOptions = apiLayerService.tlsOptions;
-    const httpsServer = https.createServer(tlsOptions, app);
+    httpsServer = https.createServer(tlsOptions, app);
     httpsServer.listen(args.port, function () {
         console.log(`${args.serviceId} service listening on port ${args.port}`);
         apiLayerService.connectToEureka();
     });
 }
 
 startHttpsService();
+
+process.on('SIGTERM', signal => {
+    apiLayerService.unregisterFromEureka();
+    httpsServer.close(() => {
+        process.exit(0);
+    });
+});
+
+process.on('SIGINT', signal => {
+    apiLayerService.unregisterFromEureka();
+    httpsServer.close(() => {
+        process.exit(0);
+    });
+});
+
+process.on('uncaughtException', err => {
+    apiLayerService.unregisterFromEureka();
+    httpsServer.close(() => {
+        process.exit(1);
+    });
+});
+
+process.on('unhandledRejection', (reason, promise) => {
+    apiLayerService.unregisterFromEureka();
+    httpsServer.close(() => {
+        process.exit(1);
+    });
+});

onboarding-enabler-nodejs/README.md

@@ -18,6 +18,18 @@ This is the onboarding Node.js enabler for [Zowe API Mediation Layer](https://gi
         apiLayerService.connectToEureka();
     });
 
+    ```
+   To make sure that your application will automatically unregister from Eureka once shut down, you can use the `unregisterFromEureka()` function, like shown in the example below.
+   **Example:**
+   
+    ```js
+    process.on('SIGINT', signal => {
+        apiLayerService.unregisterFromEureka();
+        httpsServer.close(() => {
+            process.exit(0);
+        });
+    });   
+        
     ```
 
 3. Create a yaml file named `service-configuration.yml`, add the configuration properties and place the yaml file inside a `/config` directory at the same level of your `index.js`. 

onboarding-enabler-nodejs/src/index.js

@@ -17,7 +17,9 @@ let keyFile = null;
 let caFile = null;
 let passPhrase = null;
 
-// Read ssl service configuration
+/**
+ * Read ssl service configuration
+ */
 function readTlsProps() {
     try {
         const config = yaml.load(fs.readFileSync('config/service-configuration.yml', 'utf8'));
@@ -47,6 +49,9 @@ const client = new Eureka({
     }
 });
 
+/**
+ * Function that uses the eureka-js-client library to register the application to Eureka
+ */
 function connectToEureka() {
     client.start(function(error) {
         if (error != null) {
@@ -55,9 +60,17 @@ function connectToEureka() {
     });
 }
 
+/**
+ * Unregister the Eureka client from Eureka (i.e. when the application down)
+ */
+function unregisterFromEureka() {
+    console.log("\nUnregistering the service from Eureka...")
+    client.stop();
+}
+
 connectToEureka();
 
-module.exports = {connectToEureka, tlsOptions};
+module.exports = {connectToEureka, tlsOptions, unregisterFromEureka};