From d5880e2bcf01fba7421fdc9a285f695c2fa745d8 Mon Sep 17 00:00:00 2001
From: Benoit Chesneau <bchesneau@gmail.com>
Date: Fri, 29 Jan 2010 19:04:43 +0100
Subject: [PATCH] add pidfile support. gunicorn --pid=/tmp/gunicorn.pid or
 paster server prod.ini pid=/tmp/gunicorn.pid

---
 gunicorn/arbiter.py | 71 +++++++++++++++++++++++++++++++++++++++++++--
 gunicorn/main.py    | 21 ++++++++++++--
 2 files changed, 86 insertions(+), 6 deletions(-)

diff --git a/gunicorn/arbiter.py b/gunicorn/arbiter.py
index e4eee544..b95f76eb 100644
--- a/gunicorn/arbiter.py
+++ b/gunicorn/arbiter.py
@@ -3,6 +3,8 @@
 # This file is part of gunicorn released under the MIT license. 
 # See the NOTICE for more information.
 
+from __future__ import with_statement
+
 import errno
 import fcntl
 import logging
@@ -11,12 +13,14 @@ import select
 import signal
 import socket
 import sys
+import tempfile
 import time
 
 from gunicorn.worker import Worker
 
 class Arbiter(object):
     
+    
     LISTENER = None
     WORKERS = {}    
     PIPE = []
@@ -32,19 +36,78 @@ class Arbiter(object):
         if name[:3] == "SIG" and name[3] != "_"
     )
     
-    def __init__(self, address, num_workers, modname, debug=False):
+    _pidfile = None
+    
+    def __init__(self, address, num_workers, modname, 
+            **kwargs):
         self.address = address
         self.num_workers = num_workers
         self.modname = modname
         self.timeout = 30
         self.reexec_pid = 0
         self.pid = os.getpid()
-        self.debug = debug
+        self.debug = kwargs.get("debug", False)
         self.log = logging.getLogger(__name__)
         self.init_signals()
         self.listen(self.address)
+        self.pidfile = kwargs.get("pidfile")
         self.log.info("Booted Arbiter: %s" % os.getpid())
         
+    
+    def _del_pidfile(self):
+        self._pidfile = None
+        
+    def _get_pidfile(self):
+        return self._pidfile
+        
+    def _set_pidfile(self, path):
+        if not path:
+            return
+            
+        pid = self.valid_pidfile(path)
+        if pid:
+            if self.pidfile and path == self.pidfile and pid == os.getpid():
+                return path
+            raise RuntimeError("Already running on PID %s " \
+                        "(or pid file '%s' is stale)" % (os.getpid(), path))
+        if self.pidfile:    
+            self.unlink_pidfile(self.pidfile)
+
+        # write pidfile
+        fd, fname = tempfile.mkstemp()
+        os.write(fd, "%s\n" % self.pid)
+        os.rename(fname, path)
+        os.close(fd)
+        self._pidfile = path
+    pidfile = property(_get_pidfile, _set_pidfile, _del_pidfile)
+    
+         
+    def unlink_pidfile(self, path):
+        try:
+            with open(path, "r") as f:
+                if int(f.read() or 0) == self.pid:
+                    os.unlink(f)
+        except:
+            pass
+        
+    def valid_pidfile(self, path):
+        try:
+            with open(path, "r") as f:
+                pid = int(f.read() or 0)
+                if pid <= 0: return
+     
+                try:
+                    os.kill(pid, 0)
+                    return pid
+                except OSError, e:
+                    if e[0] == errno.ESRCH:
+                        return
+                    raise
+        except IOError, e:
+            if e[0] == errno.ENOENT:
+                return
+            raise
+             
                     
     def init_signals(self):
         if self.PIPE:
@@ -150,8 +213,10 @@ class Arbiter(object):
                 self.stop(False)
                 sys.exit(-1)
                 
-        self.log.info("Master is shutting down.")
         self.stop()
+        self.log.info("Master is shutting down.")
+        if self.pidfile:
+            self.unlink_pidfile(self.pidfile)
         
     def handle_chld(self, sig, frame):
         self.wakeup()
diff --git a/gunicorn/main.py b/gunicorn/main.py
index 6c103ca9..4f040bf0 100644
--- a/gunicorn/main.py
+++ b/gunicorn/main.py
@@ -25,6 +25,8 @@ def options():
             help='Port to listen on. [%default]'),
         op.make_option('--workers', dest='workers', type='int',
             help='Number of workers to spawn. [%default]'),
+        op.make_option('-p','--pid', dest='pidfile',
+            help='set the background PID FILE'),
         op.make_option('--log-level', dest='loglevel', default='info',
             help='Log level below which to silence messages. [%default]'),
         op.make_option('--log-file', dest='logfile', default='-',
@@ -66,9 +68,14 @@ def main(usage, get_app):
             port = int(port)
         else:
             port = 8000
+            
+    kwargs = dict(
+        debug=opts.debug,
+        pidfile=opts.pidfile
+    )
     
     arbiter = Arbiter((host,port), workers, app, 
-                    opts.debug)
+                    **kwargs)
     arbiter.run()
     
 def paste_server(app, global_conf=None, host="127.0.0.1", port=None, 
@@ -88,7 +95,15 @@ def paste_server(app, global_conf=None, host="127.0.0.1", port=None,
     if debug:
         # we force to one worker in debug mode.
         workers = 1
+        
+    pid = kwargs.get("pid")
+    if global_conf:
+        pid = global_conf.get('pid', pid)
+        
+    kwargs = dict(
+        debug=debug,
+        pidfile=pid
+    )
 
-    arbiter = Arbiter(bind_addr, workers, app, 
-                    debug)
+    arbiter = Arbiter(bind_addr, workers, app, **kwargs)
     arbiter.run()
\ No newline at end of file