scgi: support reusing a listen socket

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

1 files changed, 17 insertions, 6 deletions

diff --git a/wsgitools/scgi/forkpool.py b/wsgitools/scgi/forkpool.py
index b090a54..8ccd579 100644
--- a/wsgitools/scgi/forkpool.py
+++ b/wsgitools/scgi/forkpool.py
@@ -168,7 +168,8 @@ class SCGIServer:
             self.state = state
 
     def __init__(self, wsgiapp, port, interface="localhost", error=sys.stderr,
-                 minworkers=2, maxworkers=32, maxrequests=1000, config={}):
+                 minworkers=2, maxworkers=32, maxrequests=1000, config={},
+                 reusesocket=None):
         """
         @param wsgiapp: is the WSGI application to be run.
         @type port: int
@@ -188,6 +189,11 @@ class SCGIServer:
         @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).
         """
         assert hasattr(error, "write")
         self.wsgiapp = wsgiapp
@@ -198,6 +204,7 @@ class SCGIServer:
         self.maxrequests = maxrequests
         self.config = config
         self.error = error
+        self.reusesocket = reusesocket
         self.server = None # becomes a socket
         # maps filedescriptors to WorkerStates
         self.workers = {}
@@ -218,10 +225,13 @@ class SCGIServer:
         """
         Serve the wsgi application.
         """
-        self.server = socket.socket()
-        self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
-        self.server.bind((self.interface, self.port))
-        self.server.listen(5)
+        if self.reusesocket is None:
+            self.server = socket.socket()
+            self.server.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
+            self.server.bind((self.interface, self.port))
+            self.server.listen(5)
+        else:
+            self.server = self.reusesocket
         self.running = True
         while self.running:
             while (len(self.workers) < self.minworkers or # less than min
@@ -254,7 +264,8 @@ class SCGIServer:
                     pid, _ = os.waitpid(0, os.WNOHANG)
             except OSError:
                 pass
-        self.server.close()
+        if self.reusesocket is None:
+            self.server.close()
         self.server = None
         self.killworkers()