Add --reload option for code reloading

Fix #526

NOTICE

@@ -54,6 +54,34 @@ LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 THE SOFTWARE.
 
+gunicorn.reloader
+-----------------
+
+Based on greins.reloader module under MIT license:
+
+2010 (c) Meebo, Inc.
+
+Permission is hereby granted, free of charge, to any person
+obtaining a copy of this software and associated documentation
+files (the "Software"), to deal in the Software without
+restriction, including without limitation the rights to use,
+copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the
+Software is furnished to do so, subject to the following
+conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+OTHER DEALINGS IN THE SOFTWARE.
+
 doc/sitemap_gen.py
 ------------------
 Under BSD License :

examples/example_gevent_reloader.py

@@ -1,35 +0,0 @@
-import logging
-import os
-import signal
-import sys
-
-def on_starting(server):
-    # use server hook to patch socket to allow worker reloading
-    from gevent import monkey
-    monkey.patch_socket()
-
-def when_ready(server):
-    def monitor():
-        modify_times = {}
-        while True:
-            for module in sys.modules.values():
-                path = getattr(module, "__file__", None)
-                if not path: continue
-                if path.endswith(".pyc") or path.endswith(".pyo"):
-                    path = path[:-1]
-                try:
-                    modified = os.stat(path).st_mtime
-                except:
-                    continue
-                if path not in modify_times:
-                    modify_times[path] = modified
-                    continue
-                if modify_times[path] != modified:
-                    logging.info("%s modified; restarting server", path)
-                    os.kill(os.getpid(), signal.SIGHUP)
-                    modify_times = {}
-                    break
-            gevent.sleep(1)
-
-    import gevent
-    gevent.spawn(monitor)

gunicorn/config.py

@@ -706,6 +706,21 @@ class Debug(Setting):
         """
 
 
+class Reload(Setting):
+    name = "reload"
+    section = 'Debugging'
+    cli = ['--reload']
+    validator = validate_bool
+    action = 'store_true'
+    default = False
+    desc = '''\
+        Restart workers when code changes.
+
+        This setting is intended for development. It will cause workers to be
+        restarted whenever application code changes.
+        '''
+
+
 class Spew(Setting):
     name = "spew"
     section = "Debugging"

gunicorn/reloader.py

@@ -0,0 +1,54 @@
+# -*- coding: utf-8 -
+#
+# This file is part of gunicorn released under the MIT license.
+# See the NOTICE for more information.
+
+import os
+import re
+import signal
+import sys
+import time
+import threading
+
+
+class Reloader(threading.Thread):
+    def __init__(self, extra_files=None, interval=1, callback=None):
+        super(Reloader, self).__init__()
+        self.setDaemon(True)
+        self._extra_files = set(extra_files or ())
+        self._extra_files_lock = threading.RLock()
+        self._interval = interval
+        self._callback = callback
+
+    def add_extra_file(self, filename):
+        with self._extra_files_lock:
+            self._extra_files.add(filename)
+
+    def get_files(self):
+        fnames = [
+            re.sub('py[co]$', 'py', module.__file__)
+            for module in sys.modules.values()
+            if hasattr(module, '__file__')
+        ]
+
+        with self._extra_files_lock:
+            fnames.extend(self._extra_files)
+
+        return fnames
+
+    def run(self):
+        mtimes = {}
+        while True:
+            for filename in self.get_files():
+                try:
+                    mtime = os.stat(filename).st_mtime
+                except OSError:
+                    continue
+                old_time = mtimes.get(filename)
+                if old_time is None:
+                    mtimes[filename] = mtime
+                    continue
+                elif mtime > old_time:
+                    if self._callback:
+                        self._callback(filename)
+            time.sleep(self._interval)

gunicorn/workers/base.py

@@ -12,6 +12,7 @@ import traceback
 
 from gunicorn import util
 from gunicorn.workers.workertmp import WorkerTmp
+from gunicorn.reloader import Reloader
 from gunicorn.http.errors import InvalidHeader, InvalidHeaderName, \
 InvalidRequestLine, InvalidRequestMethod, InvalidHTTPVersion, \
 LimitRequestLine, LimitRequestHeaders
@@ -79,6 +80,14 @@ class Worker(object):
         loop is initiated.
         """
 
+        # start the reloader
+        if self.cfg.reload:
+            def changed(fname):
+                self.log.info("Worker reloading: %s modified", fname)
+                os.kill(self.pid, signal.SIGTERM)
+                raise SystemExit()
+            Reloader(callback=changed).start()
+
         # set enviroment' variables
         if self.cfg.env:
             for k, v in self.cfg.env.items():