From fade3c989bd698948deefd0f67707f6d91aa7260 Mon Sep 17 00:00:00 2001
From: Marc Pichler <marc.pichler@dynatrace.com>
Date: Tue, 13 Sep 2022 18:25:51 +0200
Subject: [PATCH] ci(instrumentation-http): improve metrics test stability
 (#3242)

* fix(instrumentation-http): improve metrics test stability

* fix(changelog): add changelog entry.

* fix(instrumentation-http): clean up test reader.

* fix(changlog): move entry to internal

* fix(instrumentation-http): fix TestMetricReader
---
 experimental/CHANGELOG.md                     |  2 +
 .../test/functionals/http-metrics.test.ts     |  7 +--
 .../test/utils/TestMetricReader.ts            | 49 +++++++++++++++++++
 3 files changed, 55 insertions(+), 3 deletions(-)
 create mode 100644 experimental/packages/opentelemetry-instrumentation-http/test/utils/TestMetricReader.ts

diff --git a/experimental/CHANGELOG.md b/experimental/CHANGELOG.md
index f3d709a045..0c77075056 100644
--- a/experimental/CHANGELOG.md
+++ b/experimental/CHANGELOG.md
@@ -54,6 +54,8 @@ All notable changes to experimental packages in this project will be documented
 
 ### :house: (Internal)
 
+* ci(instrumentation-http): improve metrics test stability [#3242](https://github.com/open-telemetry/opentelemetry-js/pull/3242) @pichlermarc
+
 ## 0.32.0
 
 ### :boom: Breaking Change
diff --git a/experimental/packages/opentelemetry-instrumentation-http/test/functionals/http-metrics.test.ts b/experimental/packages/opentelemetry-instrumentation-http/test/functionals/http-metrics.test.ts
index 5ab046b45f..3d80bb950d 100644
--- a/experimental/packages/opentelemetry-instrumentation-http/test/functionals/http-metrics.test.ts
+++ b/experimental/packages/opentelemetry-instrumentation-http/test/functionals/http-metrics.test.ts
@@ -18,13 +18,13 @@ import {
   DataPointType,
   InMemoryMetricExporter,
   MeterProvider,
-  PeriodicExportingMetricReader,
 } from '@opentelemetry/sdk-metrics';
 import { NodeTracerProvider } from '@opentelemetry/sdk-trace-node';
 import { SemanticAttributes } from '@opentelemetry/semantic-conventions';
 import * as assert from 'assert';
 import { HttpInstrumentation } from '../../src/http';
 import { httpRequest } from '../utils/httpRequest';
+import { TestMetricReader } from '../utils/TestMetricReader';
 
 const instrumentation = new HttpInstrumentation();
 instrumentation.enable();
@@ -40,7 +40,8 @@ const pathname = '/test';
 const tracerProvider = new NodeTracerProvider();
 const meterProvider = new MeterProvider();
 const metricsMemoryExporter = new InMemoryMetricExporter(AggregationTemporality.DELTA);
-const metricReader = new PeriodicExportingMetricReader({ exporter: metricsMemoryExporter, exportIntervalMillis: 100 });
+const metricReader = new TestMetricReader(metricsMemoryExporter);
+
 meterProvider.addMetricReader(metricReader);
 instrumentation.setTracerProvider(tracerProvider);
 instrumentation.setMeterProvider(meterProvider);
@@ -69,7 +70,7 @@ describe('metrics', () => {
     for (let i = 0; i < requestCount; i++) {
       await httpRequest.get(`${protocol}://${hostname}:${serverPort}${pathname}`);
     }
-    await new Promise(resolve => setTimeout(resolve, 300));
+    await metricReader.collectAndExport();
     const resourceMetrics = metricsMemoryExporter.getMetrics();
     const scopeMetrics = resourceMetrics[0].scopeMetrics;
     assert.strictEqual(scopeMetrics.length, 1, 'scopeMetrics count');
diff --git a/experimental/packages/opentelemetry-instrumentation-http/test/utils/TestMetricReader.ts b/experimental/packages/opentelemetry-instrumentation-http/test/utils/TestMetricReader.ts
new file mode 100644
index 0000000000..53ea687d64
--- /dev/null
+++ b/experimental/packages/opentelemetry-instrumentation-http/test/utils/TestMetricReader.ts
@@ -0,0 +1,49 @@
+/*
+ * 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 {
+  MetricReader,
+  PushMetricExporter
+} from '@opentelemetry/sdk-metrics';
+
+export class TestMetricReader extends MetricReader {
+  constructor(private _exporter: PushMetricExporter) {
+    super({
+      aggregationTemporalitySelector: _exporter.selectAggregationTemporality?.bind(_exporter),
+    });
+  }
+
+  protected onForceFlush(): Promise<void> {
+    return Promise.resolve(undefined);
+  }
+
+  protected onShutdown(): Promise<void> {
+    return Promise.resolve(undefined);
+  }
+
+  public async collectAndExport(): Promise<void> {
+    const result = await this.collect();
+    await new Promise<void>((resolve, reject) => {
+      this._exporter.export(result.resourceMetrics, result => {
+        if (result.error != null) {
+          reject(result.error);
+        } else {
+          resolve();
+        }
+      });
+    });
+  }
+}