Update metrics example

examples/metrics/metrics/observer.js

@@ -23,16 +23,23 @@ const meter = new MeterProvider({
   interval: 2000,
 }).getMeter('example-meter');
 
-meter.createObservableGauge('cpu_core_usage', async (observableResult) => { // this callback is called once per each interval
-  await new Promise((resolve) => {
-    setTimeout(() => { resolve(); }, 50);
-  });
-  observableResult.observe(getRandomValue(), { core: '1' });
-  observableResult.observe(getRandomValue(), { core: '2' });
-}, {
-  description: 'Example of a sync observable gauge with callback',
+// async callback - for operation that needs to wait for value
+meter.createObservableGauge('cpu_core_usage', {
+  description: 'Example of an async observable gauge with callback',
+}, async (observableResult) => {
+  const value = await getAsyncValue();
+  observableResult.observe(value, { core: '1' });
+  observableResult.observe(value, { core: '2' });
 });
 
-function getRandomValue() {
-  return Math.random();
+function getAsyncValue() {
+  return new Promise((resolve) => {
+    setTimeout(()=> {
+      resolve(Math.random());
+    }, 100);
+  });
 }
+
+setInterval(function(){
+  console.log("simulating an app being kept open")
+}, 5000);

examples/metrics/package.json

@@ -27,9 +27,9 @@
   },
   "dependencies": {
     "@opentelemetry/api": "^1.0.2",
-    "@opentelemetry/core": "0.25.0",
-    "@opentelemetry/exporter-prometheus": "0.25.0",
-    "@opentelemetry/sdk-metrics-base": "0.25.0"
+    "@opentelemetry/core": "^1.0.1",
+    "@opentelemetry/exporter-prometheus": "^0.27.0",
+    "@opentelemetry/sdk-metrics-base": "^0.27.0"
   },
   "homepage": "https://github.com/open-telemetry/opentelemetry-js#readme"
 }