[fix] Ensure pidFile is written to disk (and updated on restart) by b…

…in/monitor

bin/monitor

@@ -1,10 +1,22 @@
-var path = require('path'),
+var fs = require('fs'),
+    path = require('path'),
     forever = require(path.resolve(__dirname, '..', 'lib', 'forever')),
     started;
 
 //
-// ### @function (options)
+// ### @function (file, pid)
+// #### @file {string} Location of the pid file.
+// #### @pid {number} pid to write to disk.
+// Write the pidFile to disk for later use
+//
+function writePid(file, pid) {
+  fs.writeFileSync(file, pid, 'utf8');
+}
+
+//
+// ### @function start (options)
 // #### @options {Object} Options for the `forever.Monitor` instance.
+// Starts the child process and disconnects from the IPC channel.
 //
 function start(options) {
   var script = process.argv[2],
@@ -14,14 +26,31 @@ function start(options) {
   monitor.start();
 
   monitor.on('start', function () {
+    //
     // This starts an nssocket server, which the forever CLI uses to
     // communicate with this monitor process after it's detached.
     // Without this, `forever list` won't show the process, even though it
     // would still be running in the background unaffected.
+    //
     forever.startServer(monitor);
+
+    //
     // Disconnect the IPC channel, letting this monitor's parent process know
     // that the child has started successfully.
+    //
     process.disconnect();
+
+    //
+    // Write the pidFile to disk
+    //
+    writePid(options.pidFile, monitor.child.pid);
+  });
+
+  //
+  // When the monitor restarts update the pid in the pidFile
+  //
+  monitor.on('restart', function () {
+    writePid(options.pidFile, monitor.child.pid);
   });
 }