commit changes from @davisp + some fixes

gunicorn/app/base.py

@@ -21,6 +21,7 @@ class Application(object):
     def __init__(self, usage=None):
         self.log = logging.getLogger(__name__)
         self.cfg = Config(usage)
+        self.callable = None
         
         parser = self.cfg.parser()
         opts, args = parser.parse_args()
@@ -67,6 +68,11 @@ class Application(object):
     
     def load(self):
         raise NotImplementedError
+        
+    def wsgi(self):
+        if self.callable is None:
+            self.callable = self.load()
+        return self.callable
     
     def run(self):
         if self.cfg.spew:

gunicorn/app/djangoapp.py

@@ -51,6 +51,8 @@ class DjangoApplicationCommand(Application):
     
     def __init__(self, options, admin_media_path):
         self.cfg = Config()
+        self.callable = None
+        
         for k, v in list(options.items()):
             if k.lower() in self.cfg.settings and v is not None:
                 self.cfg.set(k.lower(), v)

gunicorn/app/pasterapp.py

@@ -63,6 +63,7 @@ class PasterServerApplication(Application):
     def __init__(self, app, gcfg=None, host="127.0.0.1", port=None, *args, **kwargs):
         self.cfg = Config()
         self.app = app
+        self.callable = None
 
         cfg = kwargs.copy()
 

gunicorn/arbiter.py

@@ -45,12 +45,11 @@ class Arbiter(object):
     )
     
     def __init__(self, app):
+        self.app = app
         self.cfg = app.cfg
         
         if self.cfg.preload_app:
-            self.app = app.load()
-        else:
-            self.app = app
+            self.app.wsgi()
 
         self.log = logging.getLogger(__name__)
 

gunicorn/config.py

@@ -349,6 +349,21 @@ with Setting("spew") as s:
         This is the nuclear option.    
         """)
 
+with Setting("preload_app") as s:
+    s.section = "Server Mechanics"
+    s.cli = ["--preload"]
+    s.validator = validate_bool
+    s.action = "store_true"
+    s.default = False
+    s.fmt_desc("""\
+        Load application code before the worker processes are forked.
+        
+        By preloading an application you can save some RAM resources as well as
+        speed up server boot times. Although, if you defer application loading
+        to each worker process, you can reload your application code easily by
+        restarting workers.
+        """)
+
 with Setting("daemon") as s:
     s.section = "Server Mechanics"
     s.cli = ["-D", "--daemon"]
@@ -522,13 +537,3 @@ with Setting("pre_exec") as s:
         
         The callable needs to accept a single instance variable for the Arbiter.
         """)
-
-with Setting("preload_app") as s:
-    s.section = "Server Mechanic"
-    s.cli = ["--preload"]
-    s.validator = validate_bool
-    s.action = "store_true"
-    s.default = False
-    s.fmt_desc("""\
-        Enabling this preloads an application before forking worker processes.    
-        """)

gunicorn/workers/async.py

@@ -57,7 +57,7 @@ class AsyncWorker(Worker):
             environ = req.read()
             if not environ or not req.parser.headers:
                 return False
-            respiter = self.app(environ, req.start_response)
+            respiter = self.wsgi(environ, req.start_response)
             if respiter == ALREADY_HANDLED:
                 return False
             for item in respiter:

gunicorn/workers/base.py

@@ -91,9 +91,7 @@ class Worker(object):
         util.close_on_exec(self.fd)
         self.init_signals()
         
-        # do we need to load the app
-        if not self.cfg.preload_app:
-            self.app = self.app.load()
+        self.wsgi = self.app.wsgi()
         
         # Enter main run loop
         self.run()

gunicorn/workers/gtornado.py

@@ -50,9 +50,9 @@ class TornadoWorker(Worker):
         # Assume the app is a WSGI callable if its not an
         # instance of tornardo.web.Application
         if not isinstance(self.app, tornado.web.Application):
-            self.app = WSGIContainer(self.app)
+            self.app = WSGIContainer(self.wsgi)
 
-        server = HTTPServer(self.app, io_loop=self.ioloop)
+        server = HTTPServer(self.wsgi, io_loop=self.ioloop)
         server._socket = self.socket
         server.start(num_processes=1)
 

gunicorn/workers/sync.py

@@ -94,7 +94,7 @@ class SyncWorker(Worker):
             environ = req.read()
             if not environ or not req.parser.status_line:
                 return
-            respiter = self.app(environ, req.start_response)
+            respiter = self.wsgi(environ, req.start_response)
             for item in respiter:
                 req.response.write(item)
             req.response.close()