- Users can define custom metadata via comments (must be valid yaml)

- Added js-yaml dependency
DependableSystemsLab · Jun 13, 2018 · 7060821 · 7060821
1 parent 2f1d141
commit 7060821
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Showing 3 changed files with 37 additions and 11 deletions.
diff --git a/lib/core/CodeV3.js b/lib/core/CodeV3.js
@@ -6,6 +6,7 @@ var EventEmitter = require('events').EventEmitter;
 var esprima = require('esprima');
 var escodegen = require('escodegen');
 var pidusage = require('pidusage');
+var yaml = require('js-yaml');
 var jsBeautify = require('js-beautify').js_beautify;
 var chalk = require('chalk');
 var Pubsub = require('./Pubsub.js');
@@ -580,19 +581,34 @@ Code.prototype.kill = function(){
 	})
 }
 
+Code._extractMeta = function(comments){
+	var meta = {};
+	for (var i=0; i < comments.length; i++){
+		if (comments[i].type === 'Block' && comments[i].value.indexOf('things.meta') === 0){
+			var body = comments[i].value.split('\n').slice(1,-1).join('\n');
+			meta = yaml.safeLoad(body);
+			break;
+		}
+	}
+	return meta;
+}
+
 /**
  * Return instrumented code string
  * @param {string} raw_code
  */
 Code.instrument = function(pubsub, code_name, raw_code){
 	// var started = Date.now();
-	var ast = esprima.parse(raw_code);
+	var ast = esprima.parse(raw_code, { comment: true });	// Comment may contain meta info
 
 	var root_scope = new StaticScope('root');		// Create root scope (static scope)
 	var hook = new AstHook(root_scope, ast);		// Process the AST
 
+	// Process metadata about the program
+	var meta = JSON.stringify(Code._extractMeta(ast.comments));
+
 	// Prepare the things-js template
-	var template_str = `(function(${SCOPE_PREFIX}){})(require('things-js').bootstrap('${pubsub.url}', '${code_name}'));`;
+	var template_str = `(function(${SCOPE_PREFIX}){})(require('things-js').bootstrap('${pubsub.url}', '${code_name}', ${meta}));`;
 	var template = esprima.parse(template_str);
 	// WARNING: the following depends on esprima output, and might break if esprima changes its format
 	template.body[0].expression.callee.body.body = ast.body;
@@ -643,7 +659,9 @@ Code.fromSnapshot = function(snapshot, dummy_pubsub){
 		content += Timer.generateCode(snapshot.timers[id]);
 	});
 
-	code.source = `(function(${SCOPE_PREFIX}){ ${content} })(require('things-js').bootstrap('${code.pubsub.url}', '${snapshot.meta.code_name}/${snapshot.meta.instance_id}'));`;
+	var meta = JSON.stringify(snapshot.meta.extra);
+
+	code.source = `(function(${SCOPE_PREFIX}){ ${content} })(require('things-js').bootstrap('${code.pubsub.url}', '${snapshot.meta.code_name}/${snapshot.meta.instance_id}', ${meta}));`;
 	// console.log(jsBeautify(code.source));
 	// code.source = jsBeautify(code.source);
 
@@ -1209,11 +1227,13 @@ ImmediateTimer.prototype.resume = ImmediateTimer.prototype.start;
 var MasterIPCHandler = {
 	'init': function(proc, payload){
 		proc.id = payload.id;
+		proc.meta = payload.meta;
 		proc.status = Process.Status.RUNNING;
 		proc.emit('started', proc.id);
 		proc.code.pubsub.publish(PROGRAM_MONITOR_NAMESPACE, {
 			code_name: proc.code.name,
 			instance_id: proc.id,
+			meta: proc.meta,
 			status: proc.status,
 			source: proc.code.source
 		});
@@ -1257,6 +1277,7 @@ function Process(code, options, history){
 	var started, ended, elapsed;
 	self.code = code;
 	self.obj = child_process.fork(path.join(__dirname, 'vm.js'));
+	self.meta = {};
 
 	self.status = Process.Status.READY;
 	self.snapshots = [];
@@ -1541,16 +1562,17 @@ ProxyPubsub.prototype.publish = function(topic, message){
 	process.send({ ctrl: 'publish', payload: { topic: topic, message: message } });
 }
 
-function RootScope(pubsub_url, code_uri){
-	if (!(this instanceof RootScope)) return new RootScope(pubsub_url, code_uri);
+function RootScope(pubsub_url, code_uri, user_meta){
+	if (!(this instanceof RootScope)) return new RootScope(pubsub_url, code_uri, user_meta);
 	Scope.call(this, null, null, null, null, SCOPE_PREFIX);
 	var self = this;
 	var identity = code_uri.split('/');
 	// this.uid = SCOPE_PREFIX;
 	this.meta = {
 		pubsub: (process.connected ? new ProxyPubsub(pubsub_url) : new Pubsub(pubsub_url) ),
 		code_name: identity[0],
-		instance_id: (identity[1] || helpers.randKey())
+		instance_id: (identity[1] || helpers.randKey()),
+		extra: user_meta
 	};
 	this.timers = {};
 	// this.root = undefined;
@@ -1559,7 +1581,7 @@ function RootScope(pubsub_url, code_uri){
 	this.console = new ProxyConsole(this);
 
 	if (process.connected){
-		process.send({ ctrl: 'init', payload: { id: this.meta.instance_id } });
+		process.send({ ctrl: 'init', payload: { id: this.meta.instance_id, meta: user_meta } });
 		process.on('message', function(message){
 			if (message.ctrl in RuntimeHandler){
 				var result = RuntimeHandler[message.ctrl](self, message.kwargs);
@@ -1593,15 +1615,18 @@ RootScope.prototype.snapshot = function(){
 		meta : {
 			pubsub: this.meta.pubsub.url,
 			code_name: this.meta.code_name,
-			instance_id: this.meta.instance_id
+			instance_id: this.meta.instance_id,
+			extra: this.meta.extra
 		},
 		timers: {},
 		tree: undefined
 	}
 
+	// Capture scope tree
 	var scope_tree = this.extractor();
 	snapshot.tree = scope_tree;
 
+	// Capture pending timer events
 	Object.values(this.timers).forEach(function(timer){
 		snapshot.timers[timer.id] = timer.getSerializable();
 	});
@@ -1699,8 +1724,8 @@ RootScope.prototype.clearInterval = RootScope.prototype.clearTimer;
 RootScope.prototype.clearTimeout = RootScope.prototype.clearTimer;
 RootScope.prototype.clearImmediate = RootScope.prototype.clearTimer;
 
-Code.bootstrap = function(pubsub_url, code_uri){
-	return new RootScope(pubsub_url, code_uri);
+Code.bootstrap = function(pubsub_url, code_uri, user_meta){
+	return new RootScope(pubsub_url, code_uri, user_meta);
 }
 
 module.exports = Code;
diff --git a/package.json b/package.json
@@ -30,6 +30,7 @@
     "esprima": "^4.0.0",
     "express": "^4.16.2",
     "js-beautify": "^1.7.4",
+    "js-yaml": "^3.12.0",
     "jsonschema": "^1.2.0",
     "mongodb": "^2.2.33",
     "mongoose": "^5.0.17",

diff --git a/samples/motion_detector.js b/samples/motion_detector.js
@@ -20,7 +20,7 @@ var alarm_channel = 'things-videostream/alarm';
 var threshold = 0.10;
 /* end of configurable variables */
 
-var pubsub = new things.Pubsub('motion-worker-1', pubsub_url);
+var pubsub = new things.Pubsub(pubsub_url);
 
 function formatTime(ms){
 	return ('00'+Math.floor((ms/1000) / 60).toString()).slice(-2)+":"+('00'+(Math.floor(ms/1000) % 60).toString()).slice(-2)+"."+('000'+(ms%1000)).slice(-3)