scgi: support reusing a listen socket

This is useful when used in combination with e.g. systemd.

1 files changed, 15 insertions, 6 deletions

diff --git a/wsgitools/scgi/asynchronous.py b/wsgitools/scgi/asynchronous.py
index 75f1ff0..e1dbcc6 100644
--- a/wsgitools/scgi/asynchronous.py
+++ b/wsgitools/scgi/asynchronous.py
@@ -191,7 +191,7 @@ class SCGIServer(asyncore.dispatcher):
     multiple threads."""
     def __init__(self, wsgiapp, port, interface="localhost", error=sys.stderr,
                  maxrequestsize=None, maxpostsize=None, blocksize=None,
-                 config={}):
+                 config={}, reusesocket=None):
         """
         @param wsgiapp: is the wsgi application to be run.
         @type port: int
@@ -215,8 +215,16 @@ class SCGIServer(asyncore.dispatcher):
         @type config: {}
         @param config: the environ dictionary is updated using these values for
                 each request.
+        @type reusesocket: None or socket.socket
+        @param reusesocket: If a socket is passed, do not create a socket.
+                Instead use given socket as listen socket. The passed socket
+                must be set up for accepting tcp connections (i.e. AF_INET,
+                SOCK_STREAM with bind and listen called).
         """
-        asyncore.dispatcher.__init__(self)
+        if reusesocket is None:
+            asyncore.dispatcher.__init__(self)
+        else:
+            asyncore.dispatcher.__init__(self, reusesocket)
 
         self.wsgiapp = wsgiapp
         self.error = error
@@ -229,10 +237,11 @@ class SCGIServer(asyncore.dispatcher):
             self.conf["blocksize"] = blocksize
         self.conf["config"] = config
 
-        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
-        self.set_reuse_addr()
-        self.bind((interface, port))
-        self.listen(5)
+        if reusesocket is None:
+            self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
+            self.set_reuse_addr()
+            self.bind((interface, port))
+            self.listen(5)
 
     def handle_accept(self):
         """asyncore interface"""