chore(examples): lint examples/express using shared top-level eslint config

examples/express/.eslintrc.js

@@ -0,0 +1,26 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+'use strict';
+
+const baseConfig = require('../../eslint.config');
+
+module.exports = {
+  ...baseConfig,
+  env: {
+    node: true,
+  },
+};

examples/express/package.json

@@ -4,6 +4,8 @@
   "version": "0.1.0",
   "description": "Example of Express integration with OpenTelemetry",
   "scripts": {
+    "lint": "eslint . --ext=ts,js,mjs",
+    "lint:fix": "eslint . --ext=ts,js,mjs --fix",
     "server": "ts-node src/server.ts",
     "client": "ts-node src/client.ts",
     "compile": "tsc -p ."

examples/express/src/client.ts

@@ -1,32 +1,57 @@
-'use strict';
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
-// eslint-disable-next-line import/order
-import { setupTracing } from "./tracer";
-const tracer = setupTracing('example-express-client');
+// eslint-disable-next-line import/order, import/extensions
+import { setupTracing } from './tracer';
 
 import * as api from '@opentelemetry/api';
-import { default as axios } from 'axios';
+import * as axios from 'axios';
+
+const tracer = setupTracing('example-express-client');
 
-function makeRequest() {
+async function makeRequest() {
   const span = tracer.startSpan('client.makeRequest()', {
     kind: api.SpanKind.CLIENT,
   });
 
-  api.context.with(api.trace.setSpan(api.ROOT_CONTEXT, span), async () => {
-    try {
-      const res = await axios.get('http://localhost:8080/run_test');
-      console.log('status:', res.statusText);
-      span.setStatus({ code: api.SpanStatusCode.OK });
-    } catch (e) {
-      if (e instanceof Error) {
-        console.log('failed:', e.message);
-        span.setStatus({ code: api.SpanStatusCode.ERROR, message: e.message });
+  await api.context.with(
+    api.trace.setSpan(api.ROOT_CONTEXT, span),
+    async () => {
+      try {
+        const res = await axios.get('http://localhost:8080/run_test');
+        console.log('status:', res.statusText);
+        span.setStatus({ code: api.SpanStatusCode.OK });
+      } catch (e) {
+        if (e instanceof Error) {
+          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.'
+      );
+      setTimeout(() => {
+        console.log('Completed.');
+      }, 5000);
     }
-    span.end();
-    console.log('Sleeping 5 seconds before shutdown to ensure all records are flushed.');
-    setTimeout(() => { console.log('Completed.'); }, 5000);
-  });
+  );
 }
 
-makeRequest();
+makeRequest().catch(err => console.log(err));

examples/express/src/server.ts

@@ -1,11 +1,28 @@
-import { setupTracing } from './tracer'
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
-setupTracing('example-express-server');
+// eslint-disable-next-line import/order, import/extensions
+import { setupTracing } from './tracer';
 
 // Require in rest of modules
 import * as express from 'express';
-import { default as axios } from 'axios';
-import { RequestHandler } from "express";
+import * as axios from 'axios';
+import { RequestHandler } from 'express';
+
+setupTracing('example-express-server');
 
 // Setup express
 const app = express();
@@ -32,19 +49,21 @@ const authMiddleware: RequestHandler = (req, res, next) => {
 };
 
 app.use(express.json());
-app.get('/health', (req, res) => res.status(200).send("HEALTHY")); // endpoint that is called by framework/cluster
+app.get('/health', (req, res) => res.status(200).send('HEALTHY')); // endpoint that is called by framework/cluster
 app.get('/run_test', async (req, res) => {
   // Calls another endpoint of the same API, somewhat mimicking an external API call
-  const createdCat = await axios.post(`http://localhost:${PORT}/cats`, {
-    name: 'Tom',
-    friends: [
-      'Jerry',
-    ],
-  }, {
-    headers: {
-      Authorization: 'secret_token',
+  const createdCat = await axios.post(
+    `http://localhost:${PORT}/cats`,
+    {
+      name: 'Tom',
+      friends: ['Jerry'],
     },
-  });
+    {
+      headers: {
+        Authorization: 'secret_token',
+      },
+    }
+  );
 
   return res.status(201).send(createdCat.data);
 });

examples/express/src/tracer.ts

@@ -1,24 +1,49 @@
-'use strict';
+/*
+ * Copyright The OpenTelemetry Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
 
-import { trace, SamplingDecision, SpanKind, Attributes } from '@opentelemetry/api';
+import {
+  trace,
+  SamplingDecision,
+  SpanKind,
+  Attributes,
+} from '@opentelemetry/api';
 import { registerInstrumentations } from '@opentelemetry/instrumentation';
 import { NodeTracerProvider } from '@opentelemetry/sdk-trace-node';
-import { Sampler, AlwaysOnSampler, SimpleSpanProcessor } from '@opentelemetry/sdk-trace-base';
+import {
+  Sampler,
+  AlwaysOnSampler,
+  SimpleSpanProcessor,
+} from '@opentelemetry/sdk-trace-base';
 import { OTLPTraceExporter } from '@opentelemetry/exporter-trace-otlp-proto';
 import { Resource } from '@opentelemetry/resources';
-import { ATTR_SERVICE_NAME, ATTR_HTTP_ROUTE } from '@opentelemetry/semantic-conventions';
+import {
+  ATTR_SERVICE_NAME,
+  ATTR_HTTP_ROUTE,
+} from '@opentelemetry/semantic-conventions';
 import { ExpressInstrumentation } from '@opentelemetry/instrumentation-express';
 import { HttpInstrumentation } from '@opentelemetry/instrumentation-http';
 
+// eslint-disable-next-line import/prefer-default-export
 export const setupTracing = (serviceName: string) => {
   const exporter = new OTLPTraceExporter({});
   const provider = new NodeTracerProvider({
     resource: new Resource({
       [ATTR_SERVICE_NAME]: serviceName,
     }),
-    spanProcessors: [
-      new SimpleSpanProcessor(exporter),
-    ],
+    spanProcessors: [new SimpleSpanProcessor(exporter)],
     sampler: filterSampler(ignoreHealthCheck, new AlwaysOnSampler()),
   });
   registerInstrumentations({
@@ -36,7 +61,11 @@ export const setupTracing = (serviceName: string) => {
   return trace.getTracer(serviceName);
 };
 
-type FilterFunction = (spanName: string, spanKind: SpanKind, attributes: Attributes) => boolean;
+type FilterFunction = (
+  spanName: string,
+  spanKind: SpanKind,
+  attributes: Attributes
+) => boolean;
 
 function filterSampler(filterFn: FilterFunction, parent: Sampler): Sampler {
   return {
@@ -48,10 +77,16 @@ function filterSampler(filterFn: FilterFunction, parent: Sampler): Sampler {
     },
     toString() {
       return `FilterSampler(${parent.toString()})`;
-    }
-  }
+    },
+  };
 }
 
-function ignoreHealthCheck(spanName: string, spanKind: SpanKind, attributes: Attributes) {
-  return spanKind !== SpanKind.SERVER || attributes[ATTR_HTTP_ROUTE] !== "/health";
+function ignoreHealthCheck(
+  spanName: string,
+  spanKind: SpanKind,
+  attributes: Attributes
+) {
+  return (
+    spanKind !== SpanKind.SERVER || attributes[ATTR_HTTP_ROUTE] !== '/health'
+  );
 }