feat: Discover config files in home dir, working dir

src/config.js

@@ -1,34 +1,41 @@
 /* @flow */
+import os from 'os';
 import path from 'path';
 
 import requireUncached from 'require-uncached';
 import camelCase from 'camelcase';
 import decamelize from 'decamelize';
 
+import fileExists from './util/file-exists';
 import {createLogger} from './util/logger';
 import {UsageError, WebExtError} from './errors';
 
 const log = createLogger(__filename);
 
 type ApplyConfigToArgvParams = {|
+  // This is the argv object which will get updated by each
+  // config applied.
   argv: Object,
+  // This is the argv that only has CLI values applies to it.
+  argvFromCLI: Object,
   configObject: Object,
   options: Object,
   configFileName: string,
 |};
 
 export function applyConfigToArgv({
   argv,
+  argvFromCLI,
   configObject,
   options,
   configFileName,
 }: ApplyConfigToArgvParams): Object {
   let newArgv = {...argv};
 
   for (const option in configObject) {
-
     if (camelCase(option) !== option) {
-      throw new UsageError(`The config option "${option}" must be ` +
+      throw new UsageError(
+        `The config option "${option}" must be ` +
         `specified in camel case: "${camelCase(option)}"`);
     }
 
@@ -37,6 +44,7 @@ export function applyConfigToArgv({
       // Descend into the nested configuration for a sub-command.
       newArgv = applyConfigToArgv({
         argv: newArgv,
+        argvFromCLI,
         configObject: configObject[option],
         options: options[option],
         configFileName});
@@ -74,15 +82,19 @@ export function applyConfigToArgv({
       }
     }
 
-    // we assume the value was set on the CLI if the default value is
-    // not the same as that on the argv object as there is a very rare chance
-    // of this happening
+    // This is our best effort (without patching yargs) to detect
+    // if a value was set on the CLI instead of in the config.
+    // It looks for a default value and if the argv value is
+    // different, it assumes that the value was configured on the CLI.
 
-    const wasValueSetOnCLI = typeof(argv[option]) !== 'undefined' &&
-      (argv[option] !== defaultValue);
+    const wasValueSetOnCLI =
+      typeof argvFromCLI[option] !== 'undefined' &&
+      argvFromCLI[option] !== defaultValue;
     if (wasValueSetOnCLI) {
-      log.debug(`Favoring CLI: ${option}=${argv[option]} over ` +
+      log.debug(
+        `Favoring CLI: ${option}=${argvFromCLI[option]} over ` +
         `configuration: ${option}=${configObject[option]}`);
+      newArgv[option] = argvFromCLI[option];
       continue;
     }
 
@@ -118,3 +130,43 @@ export function loadJSConfigFile(filePath: string): Object {
   }
   return configObject;
 }
+
+type DiscoverConfigFilesParams = {|
+  getHomeDir: () => string,
+|};
+
+export async function discoverConfigFiles(
+  {getHomeDir = os.homedir}: DiscoverConfigFilesParams = {}
+): Promise<Array<string>> {
+  const magicConfigName = 'web-ext-config.js';
+
+  // Config files will be loaded in this order.
+  const possibleConfigs = [
+    // Look for a magic hidden config (preceded by dot) in home dir.
+    path.join(getHomeDir(), `.${magicConfigName}`),
+    // Look for a magic config in the current working directory.
+    path.join(process.cwd(), magicConfigName),
+  ];
+
+  const configs = await Promise.all(possibleConfigs.map(
+    async (fileName) => {
+      const resolvedFileName = path.resolve(fileName);
+      if (await fileExists(resolvedFileName)) {
+        return resolvedFileName;
+      } else {
+        log.debug(
+          `Discovered config "${resolvedFileName}" does not ` +
+          'exist or is not readable');
+        return false;
+      }
+    }
+  ));
+
+  const existingConfigs = [];
+  configs.forEach((f) => {
+    if (f) {
+      existingConfigs.push(f);
+    }
+  });
+  return existingConfigs;
+}

src/program.js

@@ -1,4 +1,5 @@
 /* @flow */
+import os from 'os';
 import path from 'path';
 import {readFileSync} from 'fs';
 
@@ -12,6 +13,7 @@ import {createLogger, consoleStream as defaultLogStream} from './util/logger';
 import {coerceCLICustomPreference} from './firefox/preferences';
 import {checkForUpdates as defaultUpdateChecker} from './util/updates';
 import {
+  discoverConfigFiles as defaultConfigDiscovery,
   loadJSConfigFile as defaultLoadJSConfigFile,
   applyConfigToArgv as defaultApplyConfigToArgv,
 } from './config';
@@ -37,6 +39,7 @@ type ExecuteOptions = {
   loadJSConfigFile?: typeof defaultLoadJSConfigFile,
   shouldExitProgram?: boolean,
   globalEnv?: string,
+  discoverConfigFiles?: typeof defaultConfigDiscovery,
 }
 
 
@@ -121,11 +124,15 @@ export class Program {
   async execute(
     absolutePackageDir: string,
     {
-      checkForUpdates = defaultUpdateChecker, systemProcess = process,
-      logStream = defaultLogStream, getVersion = defaultVersionGetter,
+      checkForUpdates = defaultUpdateChecker,
+      systemProcess = process,
+      logStream = defaultLogStream,
+      getVersion = defaultVersionGetter,
       applyConfigToArgv = defaultApplyConfigToArgv,
       loadJSConfigFile = defaultLoadJSConfigFile,
-      shouldExitProgram = true, globalEnv = WEBEXT_BUILD_ENV,
+      shouldExitProgram = true,
+      globalEnv = WEBEXT_BUILD_ENV,
+      discoverConfigFiles = defaultConfigDiscovery,
     }: ExecuteOptions = {}
   ): Promise<void> {
 
@@ -155,19 +162,46 @@ export class Program {
         });
       }
 
-      let argvFromConfig = {...argv};
+      let adjustedArgv = {...argv};
+      const configFiles = [];
+
+      if (argv.configDiscovery) {
+        log.debug(
+          'Discovering config files. ' +
+          'Set --no-config-discovery to disable');
+        const discoveredConfigs = await discoverConfigFiles();
+        configFiles.push(...discoveredConfigs);
+      } else {
+        log.debug('Not discovering config files');
+      }
+
       if (argv.config) {
-        const configFileName = path.resolve(argv.config);
+        configFiles.push(path.resolve(argv.config));
+      }
+
+      if (configFiles.length) {
+        const niceFileList = configFiles
+          .map((f) => f.replace(process.cwd(), '.'))
+          .map((f) => f.replace(os.homedir(), '~'))
+          .join(', ');
+        log.info(
+          'Applying config file' +
+          `${configFiles.length !== 1 ? 's' : ''}: ` +
+          `${niceFileList}`);
+      }
+
+      configFiles.forEach((configFileName) => {
         const configObject = loadJSConfigFile(configFileName);
-        argvFromConfig = applyConfigToArgv({
-          argv,
+        adjustedArgv = applyConfigToArgv({
+          argv: adjustedArgv,
+          argvFromCLI: argv,
           configFileName,
           configObject,
           options: this.options,
         });
-      }
+      });
 
-      await runCommand(argvFromConfig, {shouldExitProgram});
+      await runCommand(adjustedArgv, {shouldExitProgram});
 
     } catch (error) {
       if (!(error instanceof UsageError) || argv.verbose) {
@@ -289,11 +323,20 @@ Example: $0 --help run.
     },
     'config': {
       alias: 'c',
-      describe: 'Path to the config file',
+      describe: 'Path to a CommonJS config file to set ' +
+        'option defaults',
       default: undefined,
+      demand: false,
       requiresArg: true,
       type: 'string',
     },
+    'config-discovery': {
+      describe: 'Discover config files in home directory and ' +
+        'working directory. Disable with --no-config-discovery.',
+      demand: false,
+      default: true,
+      type: 'boolean',
+    },
   });
 
   program

src/util/file-exists.js

@@ -0,0 +1,37 @@
+/* @flow */
+import {fs} from 'mz';
+
+import {isErrorWithCode} from '../errors';
+
+type FileExistsOptions = {|
+  fileIsReadable: (filePath: string) => Promise<boolean>,
+|};
+
+/*
+ * Resolves true if the path is a readable file.
+ *
+ * Usage:
+ *
+ * const exists = await fileExists(filePath);
+ * if (exists) {
+ *   // ...
+ * }
+ *
+ * */
+export default async function fileExists(
+  path: string,
+  {
+    fileIsReadable = (f) => fs.access(f, fs.constants.R_OK),
+  }: FileExistsOptions = {}
+): Promise<boolean> {
+  try {
+    await fileIsReadable(path);
+    const stat = await fs.stat(path);
+    return stat.isFile();
+  } catch (error) {
+    if (isErrorWithCode(['EACCES', 'ENOENT'], error)) {
+      return false;
+    }
+    throw error;
+  }
+}

tests/unit/helpers.js

@@ -272,7 +272,7 @@ export class TCPConnectError extends ExtendableError {
 export class ErrorWithCode extends Error {
   code: string;
   constructor(code: ?string, message: ?string) {
-    super(message || 'pretend this is a system error');
+    super(`${code || ''}: ${message || 'pretend this is a system error'}`);
     this.code = code || 'SOME_CODE';
   }
 }

tests/unit/test-util/test.artifacts.js

@@ -142,7 +142,7 @@ describe('prepareArtifactsDir', () => {
          return prepareArtifactsDir(tmpPath, {asyncMkdirp: fakeAsyncMkdirp})
            .then(makeSureItFails(), (error) => {
              sinon.assert.called(fakeAsyncMkdirp);
-             assert.equal(error.message, 'an error');
+             assert.equal(error.message, 'ENOSPC: an error');
            });
        }
      ));

tests/unit/test-util/test.file-exists.js

@@ -0,0 +1,49 @@
+/* @flow */
+import path from 'path';
+
+import {assert} from 'chai';
+import {describe, it} from 'mocha';
+import {fs} from 'mz';
+
+import fileExists from '../../../src/util/file-exists';
+import {withTempDir} from '../../../src/util/temp-dir';
+import {ErrorWithCode} from '../helpers';
+
+
+describe('util/file-exists', () => {
+  it('returns true for existing files', () => {
+    return withTempDir(
+      async (tmpDir) => {
+        const someFile = path.join(tmpDir.path(), 'file.txt');
+        await fs.writeFile(someFile, '');
+
+        assert.equal(await fileExists(someFile), true);
+      });
+  });
+
+  it('returns false for non-existent files', () => {
+    return withTempDir(
+      async (tmpDir) => {
+        // This file does not exist.
+        const someFile = path.join(tmpDir.path(), 'file.txt');
+
+        assert.equal(await fileExists(someFile), false);
+      });
+  });
+
+  it('returns false for directories', () => {
+    return withTempDir(
+      async (tmpDir) => {
+        assert.equal(await fileExists(tmpDir.path()), false);
+      });
+  });
+
+  it('returns false for unreadable files', async () => {
+    const exists = await fileExists('pretend/unreadable/file', {
+      fileIsReadable: async () => {
+        throw new ErrorWithCode('EACCES', 'permission denied');
+      },
+    });
+    assert.equal(exists, false);
+  });
+});