Configure webpack-dev-server (apache#5786)

* setup devserver with correct proxy

* dev server wroking with written manifest

* add comments

* Change webpack to default port 9000 and minor js formatting

* Use hash in development.

* write to disk = true

* Take ports as argument for dev-server

* update instructions

* update instructions

* add devtools

* use mode instead of NODE_ENV

* use minicssextract for prod (like before)

* remove empty line

CONTRIBUTING.md

@@ -261,23 +261,52 @@ To parse and generate bundled files for superset, run either of the
 following commands. The `dev` flag will keep the npm script running and
 re-run it upon any changes within the assets directory.
 
-```
+```bash
 # Copies a conf file from the frontend to the backend
 npm run sync-backend
 
 # Compiles the production / optimized js & css
 npm run prod
 
-# Start a web server that manages and updates your assets as you modify them
+# Start a watcher that rebundle your assets as you modify them
 npm run dev
+
+# Start a web server that manages and updates your assets as you modify them
+npm run dev-server
 ```
 
-For every development session you will have to start a flask dev server
-as well as an npm watcher
+For every development session you will have to
 
-```
+1. Start a flask dev server
+
+```bash
+superset runserver -d
+# or specify port
 superset runserver -d -p 8081
-npm run dev
+```
+
+2. Start webpack dev server
+
+```bash
+npm run dev-server
+```
+
+This will start `webpack-dev-server` at port 9000 and you can access Superset at localhost:9000.
+By default, `webpack-dev-server` is configured for flask running at port 8088.
+
+If you start flask server at another port (e.g. 8081), you have to pass an extra argument
+`supersetPort` to `webpack-dev-server`
+
+```bash
+npm run dev-server -- --supersetPort=8081
+```
+
+You can also specify port for `webpack-dev-server`
+
+```bash
+npm run dev-server -- --port=9001
+# or with both dev-server port and superset port
+npm run dev-server -- --port=9001 --supersetPort=8081
 ```
 
 #### Upgrading npm packages

superset/assets/package.json

@@ -12,6 +12,7 @@
     "test:one": "mocha --require ignore-styles --compilers js:babel-core/register --require spec/helpers/browser.js",
     "cover": "babel-node node_modules/.bin/babel-istanbul cover _mocha -- --compilers babel-core/register --require spec/helpers/browser.js --require ignore-styles 'spec/**/*_spec.*'",
     "dev": "webpack --mode=development --colors --progress --debug --watch",
+    "dev-server": "webpack-dev-server --mode=development --progress",
     "prod": "node --max_old_space_size=4096 webpack --mode=production --colors --progress",
     "build": "webpack --mode=production --colors --progress",
     "lint": "eslint --ignore-path=.eslintignore --ext .js,.jsx .",
@@ -155,6 +156,7 @@
     "less": "^2.6.1",
     "less-loader": "^4.1.0",
     "mini-css-extract-plugin": "^0.4.0",
+    "minimist": "^1.2.0",
     "mocha": "^3.5.3",
     "npm-check-updates": "^2.14.0",
     "po2json": "^0.4.5",
@@ -170,6 +172,7 @@
     "webpack": "^4.17.1",
     "webpack-assets-manifest": "^3.0.1",
     "webpack-cli": "^2.0.10",
+    "webpack-dev-server": "^3.1.7",
     "webpack-sources": "^1.1.0"
   }
 }

superset/assets/webpack.config.js

@@ -1,15 +1,68 @@
 const path = require('path');
+const webpack = require('webpack');
 const CleanWebpackPlugin = require('clean-webpack-plugin');
 const MiniCssExtractPlugin = require('mini-css-extract-plugin');
 const WebpackAssetsManifest = require('webpack-assets-manifest');
+// Parse command-line arguments
+const parsedArgs = require('minimist')(process.argv.slice(2));
 
 // input dir
 const APP_DIR = path.resolve(__dirname, './');
-
 // output dir
 const BUILD_DIR = path.resolve(__dirname, './dist');
 
-const isDevMode = process.env.NODE_ENV !== 'production';
+const {
+  mode = 'development',
+  devserverPort = 9000,
+  supersetPort = 8088,
+} = parsedArgs;
+
+const isDevMode = mode !== 'production';
+
+const plugins = [
+  // creates a manifest.json mapping of name to hashed output used in template files
+  new WebpackAssetsManifest({
+    publicPath: true,
+    // This enables us to include all relevant files for an entry
+    entrypoints: true,
+    // Also write to disk when using devServer
+    // instead of only keeping manifest.json in memory
+    // This is required to make devServer work with flask.
+    writeToDisk: isDevMode,
+  }),
+
+  // create fresh dist/ upon build
+  new CleanWebpackPlugin(['dist']),
+];
+
+if (isDevMode) {
+  // Enable hot module replacement
+  plugins.push(new webpack.HotModuleReplacementPlugin());
+  // text loading (webpack 4+)
+  plugins.push(new MiniCssExtractPlugin({
+    filename: '[name].[hash:8].entry.css',
+    chunkFilename: '[name].[hash:8].chunk.css',
+  }));
+} else {
+  // text loading (webpack 4+)
+  plugins.push(new MiniCssExtractPlugin({
+    filename: '[name].[chunkhash].entry.css',
+    chunkFilename: '[name].[chunkhash].chunk.css',
+  }));
+}
+
+const output = {
+  path: BUILD_DIR,
+  publicPath: '/static/assets/dist/', // necessary for lazy-loaded chunks
+};
+
+if (isDevMode) {
+  output.filename = '[name].[hash:8].entry.js';
+  output.chunkFilename = '[name].[hash:8].chunk.js';
+} else {
+  output.filename = '[name].[chunkhash].entry.js';
+  output.chunkFilename = '[name].[chunkhash].chunk.js';
+}
 
 const config = {
   node: {
@@ -25,12 +78,7 @@ const config = {
     welcome: ['babel-polyfill', APP_DIR + '/src/welcome/index.jsx'],
     profile: ['babel-polyfill', APP_DIR + '/src/profile/index.jsx'],
   },
-  output: {
-    path: BUILD_DIR,
-    publicPath: '/static/assets/dist/', // necessary for lazy-loaded chunks
-    filename: '[name].[chunkhash].entry.js',
-    chunkFilename: '[name].[chunkhash].chunk.js',
-  },
+  output,
   optimization: {
     splitChunks: {
       chunks: 'all',
@@ -57,13 +105,16 @@ const config = {
       {
         test: /\.css$/,
         include: APP_DIR,
-        use: [isDevMode ? MiniCssExtractPlugin.loader : 'style-loader', 'css-loader'],
+        use: [
+          MiniCssExtractPlugin.loader,
+          'css-loader',
+        ],
       },
       {
         test: /\.less$/,
         include: APP_DIR,
         use: [
-          isDevMode ? MiniCssExtractPlugin.loader : 'style-loader',
+          MiniCssExtractPlugin.loader,
           'css-loader',
           'less-loader',
         ],
@@ -97,22 +148,25 @@ const config = {
     'react/lib/ExecutionEnvironment': true,
     'react/lib/ReactContext': true,
   },
-  plugins: [
-    // creates a manifest.json mapping of name to hashed output used in template files
-    new WebpackAssetsManifest({
-      publicPath: true,
-      entrypoints: true, // this enables us to include all relevant files for an entry
-    }),
-
-    // create fresh dist/ upon build
-    new CleanWebpackPlugin(['dist']),
-
-    // text loading (webpack 4+)
-    new MiniCssExtractPlugin({
-      filename: '[name].[chunkhash].entry.css',
-      chunkFilename: '[name].[chunkhash].chunk.css',
-    }),
-  ],
+  plugins,
+  devtool: isDevMode ? 'cheap-module-eval-source-map' : false,
+  devServer: {
+    historyApiFallback: true,
+    hot: true,
+    index: '', // This line is needed to enable root proxying
+    inline: true,
+    stats: { colors: true },
+    overlay: true,
+    port: devserverPort,
+    // Only serves bundled files from webpack-dev-server
+    // and proxy everything else to Superset backend
+    proxy: {
+      context: () => true,
+      '/': `http://localhost:${supersetPort}`,
+      target: `http://localhost:${supersetPort}`,
+    },
+    contentBase: path.join(process.cwd(), '../static/assets/dist'),
+  },
 };
 
 module.exports = config;