added config parameter 'restart' and added functionality to restart watchers on close

config.json

@@ -6,6 +6,7 @@
   "watchers": [
     {
       "device": "usb-Razer_Razer_Blade_Stealth-if01-event-kbd",
+      "restart": true,
       "grep": "EV_KEY",
       "keys": [
         {

libs/watcher.js

@@ -16,21 +16,23 @@ class Watcher {
             this[key] = config[key];
         }
         this.keyfilter = new Keyfilter(config.keys);
+        this.restart = config.restart;
         this.grep = config.grep;
         this.callback = callback;
     }
     start() {
-        if (this.process != undefined) {
-            return;
-        }
-        logger.debug('starting watcher \'' + this.device + '\'...');
-        var args = [this.device];
-        if (this.grep) {
-            args.push('|', 'grep', this.grep);
-        }
-        this.process = spawn("evtest", args);
-        this.attachListeners();
-        logger.info('watcher \'' + this.device + '\' initialized and capturing configured events');
+        return new Promise((resolve, reject) => {
+            if (this.process != undefined) {
+                return;
+            }
+            logger.debug('starting watcher \'' + this.device + '\'...');
+            var args = [this.device];
+            if (this.grep) {
+                args.push('|', 'grep', this.grep);
+            }
+            this.process = spawn("evtest", args);
+            this.attachListeners(resolve, reject);
+        });
     }
     stop() {
         if (this.process == undefined) {
@@ -40,14 +42,15 @@ class Watcher {
         this.process.kill();
         logger.info('watcher \'' + this.device + '\' stopped');
     }
-    attachListeners() {
+    attachListeners(resolve, reject) {
         if (this.process == undefined) {
             return;
         }
+        this.addSpawnListener(resolve);
+        this.addErrorListener(reject);
+        this.addCloseListener();
         this.addStdOutListener();
         this.addStdErrListener();
-        this.addCloseListener();
-        this.addErrorListener();
     }
     addStdOutListener() {
         if (this.process == undefined) {
@@ -82,6 +85,13 @@ class Watcher {
             logger.error(data);
         });
     }
+    addSpawnListener(resolve) {
+        logger.debug('adding spawn listener to watcher \'' + this.device + '\'...');
+        this.process.on('spawn', () => {
+            logger.info('watcher \'' + this.device + '\' initialized and capturing configured events');
+            resolve();
+        });
+    }
     addCloseListener() {
         if (this.process == undefined) {
             return;
@@ -91,20 +101,21 @@ class Watcher {
             if (code == undefined) {
                 code = 0;
             }
+            this.process = undefined;
             this.code = code;
             logger.info('watcher \'' + this.device + '\' finished with exit code ' + code);
             if (this.callback != undefined) {
-                this.callback(this.device);
+                this.callback(this);
             }
         });
     }
-    addErrorListener() {
+    addErrorListener(reject) {
         if (this.process == undefined) {
             return;
         }
         logger.debug('adding error listener to \'' + this.device + '\'...');
         this.process.on('error', (err) => {
-            logger.error('watcher \'' + this.device + '\' encountered an error >>> ' + err);
+            reject(logger.error('watcher \'' + this.device + '\' encountered an error >>> ' + err));
         });
     }
     check() {

libs/watchers.js

@@ -14,7 +14,7 @@ async function initialize() {
         var watcher = new Watcher(global.config.watchers[index], watcherCallback);
         try {
             await watcher.check();
-            watchers.push(watcher)
+            watchers.push(watcher);
             logger.debug('added watcher \'' + watcher.device + '\' to internal map');
         } catch(err) {
             logger.error(err);
@@ -44,9 +44,18 @@ async function stop() {
     }
 }
 
-function watcherCallback(watcher) {
+async function watcherCallback(watcher) {
+    if (watcher.restart) {
+        await watcher.start();
+        return;
+    }
     watchers.splice(watchers.findIndex((foundWatcher) => foundWatcher.device == watcher), 1);
     logger.debug('removed watcher \'' + watcher + '\' from internal map');
+    if (watchers.length === 0) {
+        logger.info('no watchers are active any longer');
+        logger.info(global.appName + ' ' + global.appVersion + ' exiting with code \'0\'');
+        process.exit(0);
+    }
 }
 
 module.exports = {

ninwa.js

@@ -5,6 +5,8 @@ const packageJSON = require('./package.json');
 
 const INTERRUPTS = ['SIGINT', 'SIGTERM'];
 
+global.appName = packageJSON.name;
+global.appVersion = packageJSON.version;
 global.config = process.argv[2] || __dirname + '/config.json';
 
 handleInterrupts();
@@ -21,7 +23,7 @@ util.fileExists(config)
     })
     .then(logger.initialize)
     .then(() => {
-        logger.info(packageJSON.name + ' ' + packageJSON.version + ' starting...');
+        logger.info(appName + ' ' + appVersion + ' starting...');
     })
     .then(watchers.initialize)
     .then(watchers.start)
@@ -32,7 +34,7 @@ util.fileExists(config)
 
 function exit(code) {
     code = code || 0;
-    logger.info(packageJSON.name + ' ' + packageJSON.version + ' exiting with code \'' + code + '\'...');
+    logger.info(appName + ' ' + appVersion + ' exiting with code \'' + code + '\'...');
     process.exit(code);
 }