add worker_int callback

fix #516

examples/example_config.py

@@ -70,7 +70,7 @@ backlog = 2048
 #
 
 workers = 1
-worker_class = 'egg:gunicorn#sync'
+worker_class = 'sync'
 worker_connections = 1000
 timeout = 30
 keepalive = 2
@@ -200,3 +200,20 @@ def pre_exec(server):
 
 def when_ready(server):
     server.log.info("Server is ready. Spwawning workers")
+
+def worker_int(worker):
+    worker.log.info("worker received INT or TERM signal")
+
+    ## get traceback info
+    import threading, sys, traceback
+    id2name = dict([(th.ident, th.name) for th in threading.enumerate()])
+    code = []
+    for threadId, stack in sys._current_frames().items():
+        code.append("\n# Thread: %s(%d)" % (id2name.get(threadId,""),
+            threadId))
+        for filename, lineno, name, line in traceback.extract_stack(stack):
+            code.append('File: "%s", line %d, in %s' % (filename,
+                lineno, name))
+            if line:
+                code.append("  %s" % (line.strip()))
+    worker.log.debug("\n".join(code))

gunicorn/config.py

@@ -1286,6 +1286,23 @@ class PostWorkerInit(Setting):
         Worker.
         """
 
+class WorkerInt(Setting):
+    name = "worker_int"
+    section = "Server Hooks"
+    validator = validate_callable(1)
+    type = six.callable
+
+    def worker_int(worker):
+        pass
+
+    default = staticmethod(worker_int)
+    desc = """\
+        Called just after a worker exited on SIGINT or SIGTERM.
+
+        The callable needs to accept one instance variable for the initialized
+        Worker.
+        """
+
 
 class PreExec(Setting):
     name = "pre_exec"

gunicorn/workers/base.py

@@ -134,6 +134,8 @@ class Worker(object):
 
     def handle_exit(self, sig, frame):
         self.alive = False
+        # worker_int callback
+        self.cfg.worker_int(self)
         sys.exit(0)
 
     def handle_error(self, req, client, addr, exc):