refactor(modules/pipeline/webpackProcess): load pipeline config in Config class

to configure pipeline specific options like TypeScript support.

At the time this has been added, `core/config` didn't handle the loading
of configuration files for pipeline related tasks yet.

This commit ensures a dapp's `pipeline.json` will be loaded and used to
configure Embark's webpack process as part of Embark's `Config` initialization.

lib/core/config.js

@@ -19,7 +19,7 @@ var Config = function(options) {
   this.chainTracker     = {};
   this.assetFiles = {};
   this.contractsFiles = [];
-  this.configDir = options.configDir || 'config/';
+  this.configDir = options.configDir || DEFAULT_CONFIG_PATH;
   this.chainsFile = options.chainsFile || './chains.json';
   this.plugins = options.plugins;
   this.logger = options.logger;
@@ -67,6 +67,7 @@ Config.prototype.loadConfigFiles = function(options) {
   this.loadCommunicationConfigFile();
   this.loadNameSystemConfigFile();
   this.loadPipelineConfigFile();
+  this.loadAssetFiles();
   this.loadContractsConfigFile();
   this.loadExternalContractsFiles();
   this.loadWebServerConfigFile();
@@ -83,6 +84,7 @@ Config.prototype.reloadConfig = function() {
   this.loadCommunicationConfigFile();
   this.loadNameSystemConfigFile();
   this.loadPipelineConfigFile();
+  this.loadAssetFiles();
   this.loadContractsConfigFile();
   this.loadExternalContractsFiles();
   this.loadChainTrackerFile();
@@ -388,10 +390,39 @@ Config.prototype.loadEmbarkConfigFile = function() {
 };
 
 Config.prototype.loadPipelineConfigFile = function() {
-  var assets = this.embarkConfig.app;
-  for(var targetFile in assets) {
-    this.assetFiles[targetFile] = this.loadFiles(assets[targetFile]);
+
+  const defaultPipelineConfig = {
+    typescript: false
+  };
+
+  let pipelineConfigPath = this._getFileOrOject(this.configDir, 'pipeline', 'pipeline');
+
+  // Embark applications in "simple" mode that aren't aware of `pipeline.js` configuration capabilities
+  // won't have a pipeline config path so we need to perform this safety check here, otherwise the
+  // next expression is going to throw.
+  if (pipelineConfigPath !== undefined) {
+    // At this point, `pipelineConfigPath` could be either `config/pipeline` or a filepath including its extension.
+    // We need to make sure that we always have an extension.
+    pipelineConfigPath = `${fs.dappPath(pipelineConfigPath)}${path.extname(pipelineConfigPath) === '.js' ? '' : '.js'}`;
   }
+
+  let pipelineConfig = defaultPipelineConfig;
+
+  if (pipelineConfigPath && fs.existsSync(pipelineConfigPath)) {
+    delete require.cache[pipelineConfigPath];
+    pipelineConfig = utils.recursiveMerge(
+      utils.recursiveMerge(true, pipelineConfig),
+      require(pipelineConfigPath)
+    );
+  }
+
+  this.pipelineConfig = pipelineConfig;
+};
+
+Config.prototype.loadAssetFiles = function () {
+  Object.keys(this.embarkConfig.app).forEach(targetFile => {
+    this.assetFiles[targetFile] = this.loadFiles(this.embarkConfig.app[targetFile]);
+  });
 };
 
 Config.prototype.loadChainTrackerFile = function() {

lib/modules/pipeline/index.js

@@ -15,6 +15,7 @@ class Pipeline {
     this.plugins = embark.config.plugins;
     this.webpackConfigName = options.webpackConfigName;
     this.pipelinePlugins = this.plugins.getPluginsFor('pipeline');
+    this.pipelineConfig = embark.config.pipelineConfig;
     this.isFirstBuild = true;
 
     this.events.setCommandHandler('pipeline:build', (options, callback) => this.build(callback));
@@ -104,7 +105,13 @@ class Pipeline {
             }
           }
         });
-        webpackProcess.send({action: constants.pipeline.init, options: {webpackConfigName: self.webpackConfigName}});
+        webpackProcess.send({
+          action: constants.pipeline.init,
+          options: {
+            webpackConfigName: self.webpackConfigName,
+            pipelineConfig: self.pipelineConfig
+          }
+        });
         webpackProcess.send({action: constants.pipeline.build, assets: self.assetFiles, importsList});
 
         webpackProcess.once('result', constants.pipeline.built, (msg) => {

lib/modules/pipeline/webpackProcess.js

@@ -3,17 +3,7 @@ const fs = require('../../core/fs');
 const ProcessWrapper = require('../../core/processes/processWrapper');
 const webpack = require('webpack');
 const writeFile = require('util').promisify(require('fs').writeFile);
-const {errorMessage, recursiveMerge} = require('../../utils/utils');
-
-// TODO: refactor into lib/core/config once pipeline is a proper embark module
-const defaultPipelineConfig = {
-  typescript: false
-};
-
-const pipelineConfigPath = fs.dappPath(
-  require(fs.dappPath('embark.json')).config || 'config/',
-  'pipeline.js'
-);
+const {errorMessage} = require('../../utils/utils');
 
 let webpackProcess;
 
@@ -21,6 +11,7 @@ class WebpackProcess extends ProcessWrapper {
   constructor(options) {
     super(options);
     this.webpackConfigName = options.webpackConfigName;
+    this.pipelineConfig = options.pipelineConfig;
   }
 
   async build(assets, importsList, callback) {
@@ -41,17 +32,9 @@ class WebpackProcess extends ProcessWrapper {
         fs.dappPath('.embark/embark-assets.json'),
         JSON.stringify(assets)
       );
-      let pipelineConfig = defaultPipelineConfig;
-      if (fs.existsSync(pipelineConfigPath)) {
-        delete require.cache[pipelineConfigPath];
-        pipelineConfig = recursiveMerge(
-          recursiveMerge(true, pipelineConfig),
-          require(pipelineConfigPath)
-        );
-      }
       await writeFile(
         fs.dappPath('.embark/embark-pipeline.json'),
-        JSON.stringify(pipelineConfig)
+        JSON.stringify(this.pipelineConfig)
       );
     } catch (e) {
       return callback(errorMessage(e));