From 2fcc2668a3edb33c5a29295f2b9c52e761ba1ca9 Mon Sep 17 00:00:00 2001
From: Spencer <email@spalger.com>
Date: Wed, 25 Dec 2019 06:27:21 -0700
Subject: [PATCH] remove use of experimental fs.promises api (#53346)

* remove use of experimental fs.promises api

* remove one more usage of fs.promises

* switch to an alternate fs module to maintain testing strategy

Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
---
 src/core/server/uuid/fs.ts                | 24 +++++++++++++++++++++++
 src/core/server/uuid/resolve_uuid.test.ts | 19 +++++-------------
 src/core/server/uuid/resolve_uuid.ts      |  4 +---
 utilities/visual_regression.js            |  6 +++---
 4 files changed, 33 insertions(+), 20 deletions(-)
 create mode 100644 src/core/server/uuid/fs.ts

diff --git a/src/core/server/uuid/fs.ts b/src/core/server/uuid/fs.ts
new file mode 100644
index 0000000000000..f10d6370c09d1
--- /dev/null
+++ b/src/core/server/uuid/fs.ts
@@ -0,0 +1,24 @@
+/*
+ * Licensed to Elasticsearch B.V. under one or more contributor
+ * license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright
+ * ownership. Elasticsearch B.V. licenses this file to you 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
+ *
+ *    http://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 Fs from 'fs';
+import { promisify } from 'util';
+
+export const readFile = promisify(Fs.readFile);
+export const writeFile = promisify(Fs.writeFile);
diff --git a/src/core/server/uuid/resolve_uuid.test.ts b/src/core/server/uuid/resolve_uuid.test.ts
index 1ddd667eacdee..d1332daa02057 100644
--- a/src/core/server/uuid/resolve_uuid.test.ts
+++ b/src/core/server/uuid/resolve_uuid.test.ts
@@ -17,31 +17,22 @@
  * under the License.
  */
 
-import { promises } from 'fs';
 import { join } from 'path';
+import { readFile, writeFile } from './fs';
 import { resolveInstanceUuid } from './resolve_uuid';
 import { configServiceMock } from '../config/config_service.mock';
 import { loggingServiceMock } from '../logging/logging_service.mock';
 import { BehaviorSubject } from 'rxjs';
 import { Logger } from '../logging';
 
-const { readFile, writeFile } = promises;
-
 jest.mock('uuid', () => ({
   v4: () => 'NEW_UUID',
 }));
 
-jest.mock('fs', () => {
-  const actual = jest.requireActual('fs');
-  return {
-    ...actual,
-    promises: {
-      ...actual.promises,
-      readFile: jest.fn(() => Promise.resolve('')),
-      writeFile: jest.fn(() => Promise.resolve('')),
-    },
-  };
-});
+jest.mock('./fs', () => ({
+  readFile: jest.fn(() => Promise.resolve('')),
+  writeFile: jest.fn(() => Promise.resolve('')),
+}));
 
 const DEFAULT_FILE_UUID = 'FILE_UUID';
 const DEFAULT_CONFIG_UUID = 'CONFIG_UUID';
diff --git a/src/core/server/uuid/resolve_uuid.ts b/src/core/server/uuid/resolve_uuid.ts
index 17412bfa0544c..3f5bdc7387392 100644
--- a/src/core/server/uuid/resolve_uuid.ts
+++ b/src/core/server/uuid/resolve_uuid.ts
@@ -18,16 +18,14 @@
  */
 
 import uuid from 'uuid';
-import { promises } from 'fs';
 import { join } from 'path';
 import { take } from 'rxjs/operators';
+import { readFile, writeFile } from './fs';
 import { IConfigService } from '../config';
 import { PathConfigType, config as pathConfigDef } from '../path';
 import { HttpConfigType, config as httpConfigDef } from '../http';
 import { Logger } from '../logging';
 
-const { readFile, writeFile } = promises;
-
 const FILE_ENCODING = 'utf8';
 const FILE_NAME = 'uuid';
 
diff --git a/utilities/visual_regression.js b/utilities/visual_regression.js
index f174dc4764aed..d95b3018bea96 100644
--- a/utilities/visual_regression.js
+++ b/utilities/visual_regression.js
@@ -103,8 +103,8 @@ async function compareScreenshots() {
 
     const diffImagePath = path.resolve(DIFF_SCREENSHOTS_DIR, screenshot);
 
-    const sessionImage = PNG.sync.read(await fs.promises.readFile(sessionImagePath));
-    const baselineImage = PNG.sync.read(await fs.promises.readFile(baselineImagePath));
+    const sessionImage = PNG.sync.read(await readFileAsync(sessionImagePath));
+    const baselineImage = PNG.sync.read(await readFileAsync(baselineImagePath));
     const { width, height } = sessionImage;
     const diff = new PNG({ width, height });
 
@@ -117,7 +117,7 @@ async function compareScreenshots() {
       { threshold: 0 }
     );
 
-    await fs.promises.writeFile(diffImagePath, PNG.sync.write(diff));
+    await writeFileAsync(diffImagePath, PNG.sync.write(diff));
 
     const change = numDiffPixels / (width * height);
     const changePercentage = (change * 100).toFixed(2);