Merge pull request #32 from mcallistersean/master

Support inherited file descriptors

README.rst

@@ -24,6 +24,21 @@ set a bind address and port (defaults to localhost, port 8000)::
     daphne -b 0.0.0.0 -p 8001 django_project.asgi:channel_layer
 
 
+If you intend to run daphne behind a proxy server you can use UNIX
+sockets to communicate between the two::
+
+    daphne -u /tmp/daphne.sock django_project.asgi:channel_layer
+
+
+If daphne is being run inside a process manager such as
+`Circus <https://github.com/circus-tent/circus/>`_ you might
+want it to bind to a file descriptor passed down from a parent process.
+To achieve this you can use the --fd flag::
+
+    daphne --fd 5 django_project.asgi:channel_layer
+
+To see all available command line options run daphne with the *-h* flag.
+
 Root Path (SCRIPT_NAME)
 -----------------------
 

daphne/cli.py

@@ -41,6 +41,13 @@ class CommandLineInterface(object):
             help='Bind to a UNIX socket rather than a TCP host/port',
             default=None,
         )
+        self.parser.add_argument(
+            '--fd',
+            type=int,
+            dest='file_descriptor',
+            help='Bind to a file descriptor rather than a TCP host/port or named unix socket',
+            default=None,
+        )
         self.parser.add_argument(
             '-v',
             '--verbosity',
@@ -133,6 +140,7 @@ class CommandLineInterface(object):
             host=args.host,
             port=args.port,
             unix_socket=args.unix_socket,
+            file_descriptor=args.file_descriptor,
             http_timeout=args.http_timeout,
             ping_interval=args.ping_interval,
             action_logger=AccessLogGenerator(access_log_stream) if access_log_stream else None,

daphne/server.py

@@ -1,6 +1,6 @@
 import logging
 from twisted.internet import reactor
-
+import socket
 from .http_protocol import HTTPFactory
 
 logger = logging.getLogger(__name__)
@@ -14,6 +14,7 @@ class Server(object):
         host="127.0.0.1",
         port=8000,
         unix_socket=None,
+        file_descriptor=None,
         signal_handlers=True,
         action_logger=None,
         http_timeout=120,
@@ -26,6 +27,7 @@ class Server(object):
         self.host = host
         self.port = port
         self.unix_socket = unix_socket
+        self.file_descriptor = file_descriptor
         self.signal_handlers = signal_handlers
         self.action_logger = action_logger
         self.http_timeout = http_timeout
@@ -48,8 +50,13 @@ class Server(object):
         )
         if self.unix_socket:
             reactor.listenUNIX(self.unix_socket, self.factory)
+        elif self.file_descriptor:
+            # socket returns the same socket if supplied with a fileno
+            sock = socket.socket(fileno=self.file_descriptor)
+            reactor.adoptStreamPort(self.file_descriptor, sock.family, self.factory)
         else:
             reactor.listenTCP(self.port, self.factory, interface=self.host)
+
         reactor.callLater(0, self.backend_reader)
         reactor.callLater(2, self.timeout_checker)
         reactor.run(installSignalHandlers=self.signal_handlers)