install npm package using shell.js

lib/core/engine.js

@@ -132,7 +132,7 @@ class Engine {
   }
 
   pluginCommandService() {
-    this.registerModule('plugin_cmd');
+    this.registerModule('plugin_cmd', {embarkConfig: this.embarkConfig});
   }
 
   namingSystem(_options) {

lib/modules/plugin_cmd/index.js

@@ -1,15 +1,54 @@
+let fs = require('./../../core/fs.js');
+let utils = require('./../../utils/utils.js');
+let async = require('async');
+
 class PluginCommand {
-  constructor(embark) {
+  constructor(embark, config) {
     this.embark = embark;
+    this.config = config;
+    this.embarkConfig = fs.readJSONSync(this.config.embarkConfig);
     this.registerCommands();
   }
   registerCommands() {
-    const self = this;
-    self.embark.registerConsoleCommand((cmd, _options) => {
+    this.embark.registerConsoleCommand((cmd, _options) => {
+      let cmdArray = cmd.split(' ');
+      let cmdName = cmdArray[0];
       return {
-        match: () => cmd === 'plugin',
-        process: (cb) => {
-          //self.events.request('start-webserver', cb)
+        match: () =>  cmdName === 'plugin',
+        process: (callback) => {
+          if(cmdArray.length < 3 || cmdArray[1] !== 'install' || typeof cmdArray[2] === 'undefined') {
+            return callback(__('arguments to the command are missing or invalid'));
+          }
+          let npmInstall = ['npm', 'install'];
+          if (cmdArray[2] === '--save') {
+            if(typeof cmdArray[3] === 'undefined') {
+              return callback(__('npm package argument missing'));
+            }
+            npmInstall = npmInstall.concat(cmdArray);
+          } else {
+            npmInstall = npmInstall.concat(['--save'].concat(cmdArray.slice(2)));
+          }
+
+          async.waterfall([
+            function npmInstallAsync(cb) {
+              utils.runCmd(npmInstall.join(' '), {silent: false, exitOnError: false}, (err) => {
+                if(err) {
+                  return cb(err);
+                }
+                cb();
+              });
+            },
+            function addToEmbarkConfig(cb) {
+              //TO DO: read from package.json and update the plugins
+              cb();
+            }
+          ], (err) => {
+            if(err) {
+              callback(__(err));
+            } else {
+              callback(null, 'npm package successfully installed as a plugin');
+            }
+          });
         }
       };
     });

lib/utils/utils.js

@@ -129,17 +129,25 @@ function pingEndpoint(host, port, type, protocol, origin, callback) {
   });
 }
 
-function runCmd(cmd, options) {
+function runCmd(cmd, options, callback) {
   const shelljs = require('shelljs');
-  let result = shelljs.exec(cmd, options || {silent: true});
+  options = options || {silent: true, exitOnError: true};
+  console.log(cmd, options, typeof callback);
+  let result = shelljs.exec(cmd);
   if (result.code !== 0) {
     console.log("error doing.. " + cmd);
     console.log(result.output);
     if (result.stderr !== undefined) {
       console.log(result.stderr);
     }
-    exit();
+    if (typeof callback === 'function') {
+      return callback(result, null);
+    }
+    if (options.exitOnError) {
+      exit();
+    }
   }
+  callback(null, result);
 }
 
 function cd(folder) {