wp-env: override generated file directory with environment var… (#20253)

- Uses a non-hidden default directory for Linux (~/wp-env)
- Allows a user to override the directory in which wp-env
  creates generated files with the WP_ENV_HOME environment
  variable.

Work towards #20180, but will need to continue in a follow-up.

packages/env/CHANGELOG.md

@@ -2,6 +2,7 @@
 
 ### New Feature
 
+- You may now override the directory in which `wp-env` creates generated files with the `WP_ENV_HOME` environment variable. The default directory is `~/.wp-env/` (or `~/wp-env/` on Linux).
 - The `.wp-env.json` coniguration file now accepts `port` and `testsPort` options which can be used to set the ports on which the docker instance is mounted.
 
 ## 1.0.0 (2020-02-10)

packages/env/README.md

@@ -137,6 +137,8 @@ $ wp-env start
 
 ## Command reference
 
+`wp-env` creates generated files in the `wp-env` home directory. By default, this is `~/.wp-env`. The exception is Linux, where files are placed at `~/wp-env` [for compatibility with Snap Packages](https://github.com/WordPress/gutenberg/issues/20180#issuecomment-587046325). The `wp-env` home directory contains a subdirectory for each project named `/$md5_of_project_path`. To change the `wp-env` home directory, set the `WP_ENV_HOME` environment variable. For example, running `WP_ENV_HOME="something" wp-env start` will download the project files to the directory `./something/$md5_of_project_path` (relative to the current directory).
+
 ### `wp-env start [ref]`
 
 ```sh

packages/env/lib/config.js

@@ -151,8 +151,7 @@ module.exports = {
 		}
 
 		const workDirectoryPath = path.resolve(
-			os.homedir(),
-			'.wp-env',
+			getHomeDirectory(),
 			md5( configPath )
 		);
 
@@ -286,6 +285,32 @@ function getNumberFromEnvVariable( varName ) {
 	return maybeNumber;
 }
 
+/**
+ * Gets the `wp-env` home directory in which generated files are created.
+ *
+ * By default, '~/.wp-env/'. On Linux, '~/wp-env/'. Can be overriden with the
+ * WP_ENV_HOME environment variable.
+ *
+ * @return {string} The absolute path to the `wp-env` home directory.
+ */
+function getHomeDirectory() {
+	// Allow user to override download location.
+	if ( process.env.WP_ENV_HOME ) {
+		return path.resolve( process.env.WP_ENV_HOME );
+	}
+
+	/**
+	 * Installing docker with Snap Packages on Linux is common, but does not
+	 * support hidden directories. Therefore we use a public directory on Linux.
+	 *
+	 * @see https://github.com/WordPress/gutenberg/issues/20180#issuecomment-587046325
+	 */
+	return path.resolve(
+		os.homedir(),
+		os.platform() === 'linux' ? 'wp-env' : '.wp-env'
+	);
+}
+
 /**
  * Hashes the given string using the MD5 algorithm.
  *

packages/env/lib/env.js

@@ -33,6 +33,19 @@ module.exports = {
 	 * @param {Object} options.spinner A CLI spinner which indicates progress.
 	 */
 	async start( { spinner } ) {
+		/**
+		 * If the Docker image is already running and the `wp-env` files have been
+		 * deleted, the start command will not complete successfully. Stopping
+		 * the container before continuing allows the docker entrypoint script,
+		 * which restores the files, to run again when we start the containers.
+		 *
+		 * Additionally, this serves as a way to restart the container entirely
+		 * should the need arise.
+		 *
+		 * @see https://github.com/WordPress/gutenberg/pull/20253#issuecomment-587228440
+		 */
+		await module.exports.stop( { spinner } );
+
 		const config = await initConfig();
 
 		spinner.text = 'Downloading WordPress.';

packages/env/test/config.js

@@ -3,6 +3,7 @@
  * External dependencies
  */
 const { readFile } = require( 'fs' ).promises;
+const os = require( 'os' );
 
 /**
  * Internal dependencies
@@ -327,6 +328,71 @@ describe( 'readConfig', () => {
 			testsPort: 8889,
 		} );
 	} );
+
+	it( 'should use the WP_ENV_HOME environment variable only if specified', async () => {
+		readFile.mockImplementation( () =>
+			Promise.resolve( JSON.stringify( {} ) )
+		);
+		const oldEnvHome = process.env.WP_ENV_HOME;
+
+		expect.assertions( 2 );
+
+		process.env.WP_ENV_HOME = 'here/is/a/path';
+		const configWith = await readConfig( '.wp-env.json' );
+		expect(
+			configWith.workDirectoryPath.includes( 'here/is/a/path' )
+		).toBe( true );
+
+		process.env.WP_ENV_HOME = undefined;
+		const configWithout = await readConfig( '.wp-env.json' );
+		expect(
+			configWithout.workDirectoryPath.includes( 'here/is/a/path' )
+		).toBe( false );
+
+		process.env.WP_ENV_HOME = oldEnvHome;
+	} );
+
+	it( 'should use the WP_ENV_HOME environment variable on Linux', async () => {
+		readFile.mockImplementation( () =>
+			Promise.resolve( JSON.stringify( {} ) )
+		);
+		const oldEnvHome = process.env.WP_ENV_HOME;
+		const oldOsPlatform = os.platform;
+		os.platform = () => 'linux';
+
+		expect.assertions( 2 );
+
+		process.env.WP_ENV_HOME = 'here/is/a/path';
+		const configWith = await readConfig( '.wp-env.json' );
+		expect(
+			configWith.workDirectoryPath.includes( 'here/is/a/path' )
+		).toBe( true );
+
+		process.env.WP_ENV_HOME = undefined;
+		const configWithout = await readConfig( '.wp-env.json' );
+		expect(
+			configWithout.workDirectoryPath.includes( 'here/is/a/path' )
+		).toBe( false );
+
+		process.env.WP_ENV_HOME = oldEnvHome;
+		os.platform = oldOsPlatform;
+	} );
+
+	it( 'should use a non-private folder on Linux', async () => {
+		readFile.mockImplementation( () =>
+			Promise.resolve( JSON.stringify( {} ) )
+		);
+		const oldOsPlatform = os.platform;
+		os.platform = () => 'linux';
+
+		expect.assertions( 2 );
+
+		const config = await readConfig( '.wp-env.json' );
+		expect( config.workDirectoryPath.includes( '.wp-env' ) ).toBe( false );
+		expect( config.workDirectoryPath.includes( 'wp-env' ) ).toBe( true );
+
+		os.platform = oldOsPlatform;
+	} );
 } );
 
 /**