Extract dockery bits from Cypress' synapsedocker plugin (#9103)

* Extract dockery bits from Cypress' synapsedocker plugin

* Update cypress/plugins/docker/index.ts

Co-authored-by: David Baker <dbkr@users.noreply.github.com>

Co-authored-by: David Baker <dbkr@users.noreply.github.com>

cypress/plugins/docker/index.ts

@@ -0,0 +1,131 @@
+/*
+Copyright 2022 The Matrix.org Foundation C.I.C.
+
+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
+
+    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.
+*/
+
+/// <reference types="cypress" />
+
+import * as os from "os";
+import * as childProcess from "child_process";
+import * as fse from "fs-extra";
+
+import PluginEvents = Cypress.PluginEvents;
+import PluginConfigOptions = Cypress.PluginConfigOptions;
+
+// A cypress plugin to run docker commands
+
+export function dockerRun(args: {
+    image: string;
+    containerName: string;
+    params?: string[];
+}): Promise<string> {
+    const userInfo = os.userInfo();
+    const params = args.params ?? [];
+
+    if (userInfo.uid >= 0) {
+        // On *nix we run the docker container as our uid:gid otherwise cleaning it up its media_store can be difficult
+        params.push("-u", `${userInfo.uid}:${userInfo.gid}`);
+    }
+
+    return new Promise<string>((resolve, reject) => {
+        childProcess.execFile('docker', [
+            "run",
+            "--name", args.containerName,
+            "-d",
+            ...params,
+            args.image,
+            "run",
+        ], (err, stdout) => {
+            if (err) reject(err);
+            resolve(stdout.trim());
+        });
+    });
+}
+
+export function dockerExec(args: {
+    containerId: string;
+    params: string[];
+}): Promise<void> {
+    return new Promise<void>((resolve, reject) => {
+        childProcess.execFile("docker", [
+            "exec", args.containerId,
+            ...args.params,
+        ], { encoding: 'utf8' }, err => {
+            if (err) reject(err);
+            else resolve();
+        });
+    });
+}
+
+export async function dockerLogs(args: {
+    containerId: string;
+    stdoutFile?: string;
+    stderrFile?: string;
+}): Promise<void> {
+    const stdoutFile = args.stdoutFile ? await fse.open(args.stdoutFile, "w") : "ignore";
+    const stderrFile = args.stderrFile ? await fse.open(args.stderrFile, "w") : "ignore";
+
+    await new Promise<void>((resolve) => {
+        childProcess.spawn("docker", [
+            "logs",
+            args.containerId,
+        ], {
+            stdio: ["ignore", stdoutFile, stderrFile],
+        }).once('close', resolve);
+    });
+
+    if (args.stdoutFile) await fse.close(<number>stdoutFile);
+    if (args.stderrFile) await fse.close(<number>stderrFile);
+}
+
+export function dockerStop(args: {
+    containerId: string;
+}): Promise<void> {
+    return new Promise<void>((resolve, reject) => {
+        childProcess.execFile('docker', [
+            "stop",
+            args.containerId,
+        ], err => {
+            if (err) reject(err);
+            resolve();
+        });
+    });
+}
+
+export function dockerRm(args: {
+    containerId: string;
+}): Promise<void> {
+    return new Promise<void>((resolve, reject) => {
+        childProcess.execFile('docker', [
+            "rm",
+            args.containerId,
+        ], err => {
+            if (err) reject(err);
+            resolve();
+        });
+    });
+}
+
+/**
+ * @type {Cypress.PluginConfig}
+ */
+export function docker(on: PluginEvents, config: PluginConfigOptions) {
+    on("task", {
+        dockerRun,
+        dockerExec,
+        dockerLogs,
+        dockerStop,
+        dockerRm,
+    });
+}