feat(server): use native V8 heapdump

.gitignore

@@ -29,6 +29,7 @@ prod-sample/nginx/origin-statics
 *.key
 sample-module-bundles
 docker-compose.test.yml
+*.heapsnapshot
 
 # misc
 .DS_Store

__tests__/integration/helpers/testRunner.js

@@ -28,7 +28,11 @@ const deepMergeObjects = require('../../../src/server/utils/deepMergeObjects');
 const prodSampleDir = path.resolve('./prod-sample/');
 const pathToDockerComposeTestFile = path.resolve(prodSampleDir, 'docker-compose.test.yml');
 
-const setUpTestRunner = async ({ oneAppLocalPortToUse, oneAppMetricsLocalPortToUse } = {}) => {
+const setUpTestRunner = async ({
+  oneAppLocalPortToUse,
+  oneAppMetricsLocalPortToUse,
+  skipBrowser = false,
+} = {}) => {
   const pathToBaseDockerComposeFile = path.resolve(prodSampleDir, 'docker-compose.yml');
   const seleniumServerPort = getRandomPortNumber();
   // create docker compose file from base with changes needed for tests
@@ -53,8 +57,11 @@ const setUpTestRunner = async ({ oneAppLocalPortToUse, oneAppMetricsLocalPortToU
       },
     }
   );
-
-  delete testDockerComposeFileContents.services['selenium-chrome'].entrypoint;
+  if (skipBrowser) {
+    delete testDockerComposeFileContents.services['selenium-chrome'];
+  } else {
+    delete testDockerComposeFileContents.services['selenium-chrome'].entrypoint;
+  }
 
   fs.writeFileSync(pathToDockerComposeTestFile, yaml.safeDump(testDockerComposeFileContents));
 
@@ -73,7 +80,7 @@ const setUpTestRunner = async ({ oneAppLocalPortToUse, oneAppMetricsLocalPortToU
   try {
     await Promise.all([
       oneAppLocalPortToUse ? waitUntilServerIsUp(`https://localhost:${oneAppLocalPortToUse}/success`, serverStartupTimeout) : Promise.resolve(),
-      waitUntilServerIsUp(`http://localhost:${seleniumServerPort}`, serverStartupTimeout),
+      skipBrowser ? Promise.resolve() : waitUntilServerIsUp(`http://localhost:${seleniumServerPort}`, serverStartupTimeout),
     ]);
   } catch (err) {
     // logWatcherDuplex will buffer the logs until piped out.
@@ -84,6 +91,10 @@ const setUpTestRunner = async ({ oneAppLocalPortToUse, oneAppMetricsLocalPortToU
     );
   }
 
+  if (skipBrowser) {
+    return {};
+  }
+
   const browser = await remote({
     logLevel: 'silent',
     protocol: 'http',
@@ -102,7 +113,7 @@ const setUpTestRunner = async ({ oneAppLocalPortToUse, oneAppMetricsLocalPortToU
   return { browser };
 };
 
-const tearDownTestRunner = async ({ browser }) => {
+const tearDownTestRunner = async ({ browser } = {}) => {
   fs.removeSync(pathToDockerComposeTestFile);
   if (browser) { await browser.deleteSession(); }
 
@@ -116,7 +127,44 @@ const tearDownTestRunner = async ({ browser }) => {
   }
 };
 
+function spawnAsync(...args) {
+  const [, , options = {}] = args;
+  return new Promise((res, rej) => {
+    const spawnedProcess = childProcess.spawn(...args);
+
+    spawnedProcess
+      .on('error', rej)
+      .on('close', (exitCode) => {
+        if (exitCode !== 0) {
+          return rej(exitCode);
+        }
+        return res(exitCode);
+      });
+
+    const { stdio = ['pipe', 'pipe', 'pipe'] } = options;
+    if (stdio[1] === 'pipe') {
+      spawnedProcess.stderr.pipe(process.stderr);
+    }
+    if (stdio[2] === 'pipe') {
+      spawnedProcess.stdout.pipe(process.stdout);
+    }
+  });
+}
+
+function sendSignal(service, signal = 'SIGKILL') {
+  return spawnAsync(
+    'docker-compose',
+    [
+      '-f', pathToDockerComposeTestFile,
+      'kill',
+      '-s', signal,
+      service,
+    ]
+  );
+}
+
 module.exports = {
   setUpTestRunner,
   tearDownTestRunner,
+  sendSignal,
 };

__tests__/integration/one-app.spec.js

@@ -16,11 +16,14 @@
 
 // Headers are under a key with a dangling underscore
 /* eslint-disable no-underscore-dangle */
+import { promises as fs } from 'fs';
+import path from 'path';
+
 import fetch from 'cross-fetch';
 import yargs, { argv } from 'yargs';
 import parsePrometheusTextFormat from 'parse-prometheus-text-format';
 
-import { setUpTestRunner, tearDownTestRunner } from './helpers/testRunner';
+import { setUpTestRunner, tearDownTestRunner, sendSignal } from './helpers/testRunner';
 import { waitFor } from './helpers/wait';
 import {
   deployBrokenModule,
@@ -1329,3 +1332,49 @@ describe('Scan app instance for console errors', () => {
     });
   }
 });
+
+describe('heapdump', () => {
+  const oneAppLocalPortToUse = getRandomPortNumber();
+
+  beforeAll(async () => {
+    await setUpTestRunner({ oneAppLocalPortToUse, skipBrowser: true });
+  });
+
+  afterAll(async () => {
+    await tearDownTestRunner();
+    await waitFor(500);
+  });
+
+  it('writes a heapdump to /tmp on a SIGUSR2 signal', async () => {
+    const tmpMountDir = path.resolve(__dirname, '../../prod-sample/one-app/tmp');
+    // set up log watchers first to avoid semblance of a race condition
+    const aboutToWritePromise = searchForNextLogMatch(/about to write a heapdump to .+/);
+    // slower in Travis than on local machines
+    const didWritePromise = searchForNextLogMatch(/wrote heapdump out to .+/, 20e3);
+    await sendSignal('one-app', 'SIGUSR2');
+
+    const aboutToWriteRaw = await aboutToWritePromise;
+    const didWriteRaw = await didWritePromise;
+
+    const aboutToWriteFilePath = aboutToWriteRaw
+      .replace(/^about to write a heapdump to /, '')
+      .replace(/".+$/, '');
+
+    const didWriteFilePath = didWriteRaw
+      .replace(/^wrote heapdump out to /, '')
+      .replace(/".+$/, '');
+
+    expect(aboutToWriteFilePath).toEqual(didWriteFilePath);
+    expect(path.dirname(didWriteFilePath)).toBe('/tmp');
+    const didWriteFile = path.basename(didWriteFilePath);
+    const dirContents = await fs.readdir(tmpMountDir);
+    expect(dirContents).toContain(didWriteFile);
+
+    const { size } = await fs.stat(path.join(tmpMountDir, didWriteFile));
+    const oneMegabyte = 1024 * 1024;
+    // at the time of writing size was observed to be 14-15MB but uncertain if this
+    // is affected by my test development
+    expect(size).toBeGreaterThanOrEqual(10 * oneMegabyte);
+    expect(size).toBeLessThanOrEqual(100 * oneMegabyte);
+  });
+});

__tests__/server/config/env/runTime.spec.js

@@ -34,7 +34,6 @@ describe('runTime', () => {
   const origEnvVarVals = {};
   [
     'NODE_ENV',
-    'NODE_HEAPDUMP_OPTIONS',
     'HTTP_PORT',
     'HTTP_METRICS_PORT',
     'HOLOCRON_MODULE_MAP_URL',
@@ -126,14 +125,6 @@ describe('runTime', () => {
     });
   });
 
-  describe('NODE_HEAPDUMP_OPTIONS', () => {
-    const heapdumpOptions = getEnvVarConfig('NODE_HEAPDUMP_OPTIONS');
-
-    it('defaults to config of not writing default heapdumps', () => {
-      expect(heapdumpOptions.defaultValue).toBe('nosignal');
-    });
-  });
-
   describe('HTTP_PORT', () => {
     const httpPort = getEnvVarConfig('HTTP_PORT');
 

__tests__/server/utils/__snapshots__/heapdump.spec.js.snap

@@ -0,0 +1,3 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`heapdump warns if --report-on-signal is set, using SIGUSR2 1`] = `"--report-on-signal listens for SIGUSR2 by default, be aware that SIGUSR2 also triggers heapdumps. Use --report-signal to avoid heapdump side-effects https://nodejs.org/api/report.html"`;