document: fix express example

examples/express/client.js

@@ -13,10 +13,11 @@ function makeRequest() {
   api.context.with(api.setSpan(api.ROOT_CONTEXT, span), async () => {
     try {
       const res = await axios.get('http://localhost:8080/run_test');
-      span.setStatus({ code: api.StatusCode.OK });
-      console.log(res.statusText);
+      console.log('status:', res.statusText);
+      span.setStatus({ code: api.SpanStatusCode.OK });
     } catch (e) {
-      span.setStatus({ code: api.StatusCode.ERROR, message: e.message });
+      console.log('failed:', e.message);
+      span.setStatus({ code: api.SpanStatusCode.ERROR, message: e.message });
     }
     span.end();
     console.log('Sleeping 5 seconds before shutdown to ensure all records are flushed.');

examples/express/package.json

@@ -32,15 +32,14 @@
     "@opentelemetry/exporter-jaeger": "^0.18.0",
     "@opentelemetry/exporter-zipkin": "^0.18.0",
     "@opentelemetry/instrumentation": "^0.18.0",
+    "@opentelemetry/instrumentation-express": "^0.15.0",
+    "@opentelemetry/instrumentation-http": "^0.18.2",
     "@opentelemetry/node": "^0.18.0",
-    "@opentelemetry/plugin-express": "file:../../plugins/node/opentelemetry-plugin-express",
-    "@opentelemetry/plugin-http": "^0.18.0",
     "@opentelemetry/tracing": "^0.18.0",
     "axios": "^0.19.0",
+    "cross-env": "^7.0.3",
     "express": "^4.17.1"
   },
   "homepage": "https://github.com/open-telemetry/opentelemetry-js#readme",
-  "devDependencies": {
-    "cross-env": "^6.0.0"
-  }
+  "devDependencies": {}
 }

examples/express/server.js

@@ -31,27 +31,24 @@ const authMiddleware = (req, res, next) => {
   }
 };
 
-async function setupRoutes() {
-  app.use(express.json());
-
-  app.get('/run_test', async (req, res) => {
-    const createdCat = await axios.post(`http://localhost:${PORT}/cats`, {
-      name: 'Tom',
-      friends: [
-        'Jerry',
-      ],
-    }, {
-      headers: {
-        Authorization: 'secret_token',
-      },
-    });
-
-    return res.status(201).send(createdCat.data);
+app.use(express.json());
+app.get('/run_test', async (req, res) => {
+  // Calls another endpoint of the same API, somewhat mimicing an external API call
+  const createdCat = await axios.post(`http://localhost:${PORT}/cats`, {
+    name: 'Tom',
+    friends: [
+      'Jerry',
+    ],
+  }, {
+    headers: {
+      Authorization: 'secret_token',
+    },
   });
-  app.use('/cats', authMiddleware, getCrudController());
-}
 
-setupRoutes().then(() => {
-  app.listen(PORT);
+  return res.status(201).send(createdCat.data);
+});
+app.use('/cats', authMiddleware, getCrudController());
+
+app.listen(PORT, () => {
   console.log(`Listening on http://localhost:${PORT}`);
 });

examples/express/tracer.js

@@ -1,37 +1,36 @@
 'use strict';
 
 const opentelemetry = require('@opentelemetry/api');
+
+// Not functionally required but gives some insight what happens behind the scenes
+const { diag, DiagConsoleLogger, DiagLogLevel } = opentelemetry;
+diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.INFO);
+
+const { registerInstrumentations } = require('@opentelemetry/instrumentation');
 const { NodeTracerProvider } = require('@opentelemetry/node');
 const { SimpleSpanProcessor } = require('@opentelemetry/tracing');
 const { JaegerExporter } = require('@opentelemetry/exporter-jaeger');
 const { ZipkinExporter } = require('@opentelemetry/exporter-zipkin');
 
-const EXPORTER = process.env.EXPORTER || '';
+const Exporter = (process.env.EXPORTER || '')
+  .toLowerCase().startsWith('z') ? ZipkinExporter : JaegerExporter;
+const { ExpressInstrumentation } = require('@opentelemetry/instrumentation-express');
+const { HttpInstrumentation } = require('@opentelemetry/instrumentation-http');
 
 module.exports = (serviceName) => {
-  const provider = new NodeTracerProvider({
-    plugins: {
-      express: {
-        enabled: true,
-        path: '@opentelemetry/plugin-express',
-      },
-      http: {
-        enabled: true,
-        path: '@opentelemetry/plugin-http',
-      },
-    },
+  const provider = new NodeTracerProvider();
+  registerInstrumentations({
+    tracerProvider: provider,
+    instrumentations: [
+      // Express instrumentation expects HTTP layer to be instrumented
+      HttpInstrumentation,
+      ExpressInstrumentation,
+    ],
   });
 
-  let exporter;
-  if (EXPORTER.toLowerCase().startsWith('z')) {
-    exporter = new ZipkinExporter({
-      serviceName,
-    });
-  } else {
-    exporter = new JaegerExporter({
-      serviceName,
-    });
-  }
+  const exporter = new Exporter({
+    serviceName,
+  });
 
   provider.addSpanProcessor(new SimpleSpanProcessor(exporter));