WIP #1186 Moved backend whitelisting to execution

config/components.json

@@ -130,7 +130,7 @@
             }
         ]
     },
-    "ExecuteJob": {
-        "executionBackend": "GME"
+    "Compute": {
+        "backends": ["local", "gme"]
     }
 }

src/common/execution/index.js

@@ -1,11 +1,48 @@
+/*globals define, requirejs */
 define([
-    './backends/GME',
-    './backends/Local'
+    'underscore',
+    'module',
 ], function(
-    GME,
-    Local
+    _,
+    module
 ) {
-    // FIXME: Add more intelligent interface here...
-    // - fetch a given backend and configure
-    return Local;
+    const Execution = {};
+    const BACKENDS = ['gme', 'local'];
+
+    Execution.getBackend = function(name) {
+        name = name.toLowerCase();
+        if (!BACKENDS.includes(name)) {
+            throw new Error(`Execution backend not found: ${name}`);
+        }
+
+        const relativePath = `backends/${name}/index`;
+        const Backend = requirejs(`deepforge/execution/${relativePath}`);
+        return new Backend();
+    };
+
+    Execution.getAvailableBackends = function() {
+        const settings = {backends: ['local', 'gme']};
+        if (require.isBrowser) {
+            const ComponentSettings = requirejs('js/Utils/ComponentSettings');
+            ComponentSettings.resolveWithWebGMEGlobal(
+                settings,
+                this.getComponentId()
+            );
+        } else {  // Running in NodeJS
+            const path = require('path');
+            const dirname = path.dirname(module.uri);
+            const deploymentSettings = JSON.parse(requirejs('text!' + dirname + '/../../../config/components.json'));
+            _.extend(settings, deploymentSettings[this.getComponentId()]);
+        }
+
+        return settings.backends;
+    };
+
+    Execution.getComponentId = function() {
+        return 'Compute';
+    };
+
+    //Execution.getProjectRoot = function() {
+
+    return Execution;
 });

src/plugins/ExecuteJob/ExecuteJob.js

@@ -98,21 +98,8 @@ define([
         this.pulseClient = new ExecPulseClient(params);
         this._execHashToJobNode = {};
 
-        this.settings = _.extend({}, DEFAULT_SETTINGS);
-        if (require.isBrowser) {
-            const ComponentSettings = requirejs('js/Utils/ComponentSettings');
-            ComponentSettings.resolveWithWebGMEGlobal(
-                this.settings,
-                this.getComponentId()
-            );
-        } else {  // Running in NodeJS
-            const path = require('path');
-            const dirname = path.dirname(module.uri);
-            const deploymentSettings = JSON.parse(requirejs('text!' + dirname + '/../../../config/components.json'));
-            _.extend(this.settings, deploymentSettings[this.getComponentId()]);
-        }
-
-        const backend = Execution.getBackend(this.settings.executionBackend);
+        const name = Execution.getAvailableBackends()[0];  // FIXME: enable the user to select one
+        const backend = Execution.getBackend(name);
         this.executor = backend.getClient(this.logger);
         this.executor.on(
             'data',