Add launchd / systemd support

README.md

@@ -11,6 +11,7 @@ Features:
  * Clustering - take advantage of multiple CPU cores
  * Properly handles SIGTERM and SIGHUP for integration with service wrappers
  * Supports POSIX operating systems (does not support Windows)
+ * Supports using sockets opened by systemd or launchd
 
 Usage:
 ------
@@ -131,7 +132,6 @@ If you want to deploy on a restricted port such as 80 or 443 without sudo, try
 Note that there are 3 layers of process spawning between the naught CLI
 and your server. So you'll want to use the `--deep` option with authbind.
 
-
 Using a service wrapper:
 ------------------------
 
@@ -160,6 +160,73 @@ When you run with `--daemon-mode false`, the process tree looks like this:
      * worker 2
      * etc
 
+Using a socket from systemd or launchd
+--------------------------------------
+
+When using naught from systemd or launchd, you must use `--daemon-mode false`.
+
+systemd and launchd can be configured to listen on a port and launch naught
+when a connection is detected on that port. The intention is that your server
+will only run when it is actually needed. systemd or launchd will provide the
+open socket to naught on a file descriptor, and naught will pass that file
+descriptor on to your server as it launches it. naught will set the
+`LISTEN_FD` environment variable to the number of the file descriptor on
+which your server should listen, which it could do like this:
+
+   ```js
+   server.listen(process.env.LISTEN_FD ? {fd: parseInt(process.env.LISTEN_FD, 10)} : (process.env.PORT || 8000));
+   ```
+
+naught automatically detects if it was launched by systemd and passes the
+socket along. For use from launchd, pass the `--launchd-socket` flag when
+starting naught, and provide the name of the key you defined in the Sockets
+dictionary in your server's launchd plist. Here is a sample plist:
+
+   ```xml
+   <?xml version="1.0" encoding="UTF-8"?>
+   <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+   <plist version="1.0">
+     <dict>
+       <key>EnvironmentVariables</key>
+       <dict>
+         <key>NODE_ENV</key>
+         <string>production</string>
+         <key>PATH</key>
+         <string>/usr/local/bin:/usr/local/sbin:/usr/bin:/bin:/usr/sbin:/sbin</string>
+       </dict>
+       <key>Label</key>
+       <string>com.example.myserver</string>
+       <key>ProgramArguments</key>
+       <array>
+         <string>/usr/local/bin/node</string>
+         <string>node_modules/.bin/naught</string>
+         <string>start</string>
+         <string>--daemon-mode</string>
+         <string>false</string>
+         <string>--launchd-socket</string>
+         <string>Listeners</string>
+         <string>server.js</string>
+       </array>
+       <key>Sockets</key>
+       <dict>
+         <key>Listeners</key>
+         <dict>
+           <key>SockFamily</key>
+           <string>IPv4v6</string>
+           <key>SockServiceName</key>
+           <integer>8000</integer>
+         </dict>
+       </dict>
+       <key>WorkingDirectory</key>
+       <string>/opt/myserver</string>
+     </dict>
+   </plist>
+   ```
+
+If you want to pass a socket in a file descriptor to naught started from some
+process other than systemd or launchd, you can set the LISTEN_FD environment
+variable to the file descriptor number when you launch naught.
+
 CLI:
 ----
 
@@ -202,6 +269,7 @@ CLI:
         --daemon-mode true
         --remove-old-ipc false
         --node-args ''
+        --launchd-socket ''
 
 
     naught stop [options] [ipc-file]

example/server.js

@@ -0,0 +1,64 @@
+// npm install express express-domain-errors express-graceful-exit
+var domain = require('domain');
+var domainError = require('express-domain-errors');
+var express = require('express');
+var gracefulExit = require('express-graceful-exit');
+var http = require('http');
+var util = require('util');
+
+var serverDomain = domain.create();
+serverDomain.run(function () {
+  var app, server;
+
+  function sendOfflineMsg() {
+    if (process.send) {
+      process.send('offline');
+    }
+  }
+
+  function doGracefulExit(err) {
+    console.log('Server shutting down');
+    gracefulExit.gracefulExitHandler(app, server);
+  }
+
+  process.on('message', function (message) {
+    if (message === 'shutdown') {
+      doGracefulExit();
+    }
+  });
+
+  app = express();
+  app.use(domainError(sendOfflineMsg, doGracefulExit));
+  app.use(gracefulExit.middleware(app));
+
+  app.get('/', function (req, res) {
+    res.set('Content-Type', 'text/plain');
+    res.send('Hello world\n');
+  });
+  app.get('/bad', function (req, res) {
+    process.nextTick(/*process.domain.intercept*/(function () {
+      nonexistentFunction();
+    }));
+  });
+
+  app.use(function (req, res, next) {
+    var err = new Error(util.format('The requested URL %s was not found on this server.', req.url));
+    err.status = 404;
+    next(err);
+  });
+
+  app.use(function (err, req, res, next) {
+    var status = err.status || 500;
+    var message = err.message || 'The server encountered an internal error or misconfiguration and was unable to complete your request.';
+    res.set('Content-Type', 'text/plain');
+    res.status(status);
+    res.send(http.STATUS_CODES[status] + '\n\n' + message + '\n');
+  });
+
+  server = app.listen(process.env.LISTEN_FD ? {fd: parseInt(process.env.LISTEN_FD, 10)} : (process.env.PORT || 8000), function () {
+    console.log('Server listening on port %d', server.address().port);
+    if (process.send) {
+      process.send('online');
+    }
+  });
+});

lib/daemon.js

@@ -22,6 +22,7 @@ function startDaemon(argv) {
   var script = argv.shift();
   var nodeArgsStr = argv.shift();
   var pidFile = argv.shift();
+  var launchdSocket = argv.shift();
 
   var naughtLog = null;
   var stderrLog = null;
@@ -187,9 +188,38 @@ function startDaemon(argv) {
     var nodeArgs = splitCmdLine(nodeArgsStr);
     var stdoutValue = (stdoutBehavior === 'inherit') ? process.stdout : stdoutBehavior;
     var stderrValue = (stderrBehavior === 'inherit') ? process.stderr : stderrBehavior;
+    var listenFd = parseInt(process.env.LISTEN_FD, 10);
+    if (!listenFd) {
+      if (parseInt(process.env.LISTEN_PID, 10) === process.pid) {
+        // systemd
+        var listenFds = parseInt(process.env.LISTEN_FDS, 10);
+        if (listenFds === 0) {
+          // systemd provided no sockets
+          // log this?
+        } else if (listenFds > 1) {
+          // systemd provided too many sockets
+          // log this?
+        } else {
+          // SD_LISTEN_FDS_START
+          listenFd = 3;
+        }
+      } else if (launchdSocket) {
+        // launchd
+        try {
+          listenFd = require('node-launchd').getSocketFileDescriptorForName(launchdSocket);
+        } catch (e) {
+          // could not get launchd socket
+        }
+      }
+    }
+    var stdio = [process.stdin, stdoutValue, stderrValue, 'ipc'];
+    if (listenFd) {
+      process.env.LISTEN_FD = stdio.length;
+      stdio.push(listenFd);
+    }
     master = spawn(process.execPath, nodeArgs.concat([path.join(__dirname, "master.js"), workerCount, script]).concat(argv), {
       env: process.env,
-      stdio: [process.stdin, stdoutValue, stderrValue, 'ipc'],
+      stdio: stdio,
       cwd: process.cwd(),
     });
     master.on('message', onMessage);

lib/main.js

@@ -52,7 +52,8 @@ var cmds = {
       "    --cwd " + CWD + "\n" +
       "    --daemon-mode true\n" +
       "    --remove-old-ipc false\n" +
-      "    --node-args ''",
+      "    --node-args ''\n" +
+      "    --launchd-socket ''",
     fn: function(argv){
       var options = {
         'worker-count': '1',
@@ -66,6 +67,7 @@ var cmds = {
         'daemon-mode': 'true',
         'remove-old-ipc': 'false',
         'node-args': '',
+        'launchd-socket': '',
       };
       var arr = chompArgv(options, argv)
         , err = arr[0]
@@ -379,7 +381,8 @@ function startScript(options, script, argv){
       options['max-log-size'],
       path.resolve(CWD, script),
       options['node-args'],
-      options['pid-file']
+      options['pid-file'],
+      options['launchd-socket']
     ].concat(argv);
     if (options['daemon-mode']) {
       startDaemonChild(args);

package.json

@@ -38,6 +38,9 @@
     "mkdirp": "~0.5.0",
     "async": "~0.9.0"
   },
+  "optionalDependencies": {
+    "node-launchd": "0.0.3"
+  },
   "bugs": {
     "url": "https://github.com/andrewrk/naught/issues"
   },