New on_reload server hook to customize how SIGHUPs spawn new workers.

doc/htdocs/configure.html

@@ -448,6 +448,21 @@ def start_server(server):
 <p>Called just after the server is started.</p>
 <p>The callable needs to accept a single instance variable for the Arbiter.</p>
 </div>
+<div class="section" id="on-reload">
+<h4><a class="toc-backref" href="#contents">on_reload</a></h4>
+<ul>
+<li><pre class="first literal-block">
+def on_reload(server):
+    for i in range(server.app.cfg.workers):
+        server.spawn_worker()
+</pre>
+</li>
+</ul>
+<p>Called during a reload from a SIGHUP signal.
+This callback should create an appropriate number of new workers.
+Old workers will be killed automatically by gunicorn, so it is not required to do so here.</p>
+<p>The callable needs to accept a single instance variable for the Arbiter.</p>
+</div>
 <div class="section" id="pre-fork">
 <h4><a class="toc-backref" href="#contents">pre_fork</a></h4>
 <ul>

gunicorn/arbiter.py

@@ -337,17 +337,17 @@ class Arbiter(object):
         """
         if self.pidfile is not None:
             self.pidfile.rename("%s.oldbin" % self.pidfile.fname)
-        
+
         self.reexec_pid = os.fork()
         if self.reexec_pid != 0:
             self.master_name = "Old Master"
             return
-            
+
         os.environ['GUNICORN_FD'] = str(self.LISTENER.fileno())
         os.chdir(self.START_CTX['cwd'])
         self.cfg.pre_exec(self)
         os.execvpe(self.START_CTX[0], self.START_CTX['args'], os.environ)
-        
+
     def reload(self):
         old_address = self.cfg.address
 
@@ -362,8 +362,7 @@ class Arbiter(object):
             self.log.info("Listening at: %s", self.LISTENER)    
 
         # spawn new workers with new app & conf
-        for i in range(self.app.cfg.workers):
-            self.spawn_worker()
+        self.cfg.on_reload(self)
         
         # unlink pidfile
         if self.pidfile is not None:
@@ -388,8 +387,7 @@ class Arbiter(object):
         """
         for (pid, worker) in self.WORKERS.items():
             try:
-                diff = time.time() - os.fstat(worker.tmp.fileno()).st_ctime
-                if diff <= self.timeout:
+                if time.time() - worker.tmp.last_update() <= self.timeout:
                     continue
             except ValueError:
                 continue
@@ -446,7 +444,7 @@ class Arbiter(object):
         pid = os.fork()
         if pid != 0:
             self.WORKERS[pid] = worker
-            return
+            return pid
 
         # Process Child
         worker_pid = os.getpid()

gunicorn/config.py

@@ -637,6 +637,21 @@ class OnStarting(Setting):
         The callable needs to accept a single instance variable for the Arbiter.
         """
 
+class OnReload(Setting):
+    name = "on_reload"
+    section = "Server Hooks"
+    validator = validate_callable(1)
+    type = "callable"
+    def on_reload(server):
+        for i in range(server.app.cfg.workers):
+            server.spawn_worker()
+    default = staticmethod(on_reload)
+    desc = """\
+        Called to recycle workers during a reload via SIGHUP.
+
+        The callable needs to accept a single instance variable for the Arbiter.
+        """
+
 class WhenReady(Setting):
     name = "when_ready"
     section = "Server Hooks"

gunicorn/workers/workertmp.py

@@ -37,6 +37,9 @@ class WorkerTmp(object):
             self._tmp.truncate(0)
             os.write(self._tmp.fileno(), "X")
 
+    def last_update(self):
+        return os.fstat(self._tmp.fileno()).st_ctime
+
     def fileno(self):
         return self._tmp.fileno()