Do not raise and crash worker on ENOTCONN error

A couple of socket operations can fail with ENOTCONN error if the
other side of the connection is not connected anymore. In that case,
let's not crash the whole worker and give a chance to accept new
connections.

In my case, the operation that sometimes fails is a "getpeername()",
which was introduced in b07532b
(v19.8.0). Someone in benoitc#1913
metionned that v19.7.1 was working fine so it matches.

Fixes benoitc#1913

gunicorn/workers/base_async.py

@@ -73,11 +73,13 @@ def handle(self, listener, client, addr):
                 self.log.debug("Error processing SSL request.")
                 self.handle_error(req, client, addr, e)
         except EnvironmentError as e:
-            if e.errno not in (errno.EPIPE, errno.ECONNRESET):
+            if e.errno not in (errno.EPIPE, errno.ECONNRESET, errno.ENOTCONN):
                 self.log.exception("Socket error processing request.")
             else:
                 if e.errno == errno.ECONNRESET:
                     self.log.debug("Ignoring connection reset")
+                elif e.errno == errno.ENOTCONN:
+                    self.log.debug("Ignoring socket not connected")
                 else:
                     self.log.debug("Ignoring EPIPE")
         except Exception as e:

gunicorn/workers/gthread.py

@@ -285,11 +285,13 @@ def handle(self, conn):
                 self.handle_error(req, conn.sock, conn.client, e)
 
         except EnvironmentError as e:
-            if e.errno not in (errno.EPIPE, errno.ECONNRESET):
+            if e.errno not in (errno.EPIPE, errno.ECONNRESET, errno.ENOTCONN):
                 self.log.exception("Socket error processing request.")
             else:
                 if e.errno == errno.ECONNRESET:
                     self.log.debug("Ignoring connection reset")
+                elif e.errno == errno.ENOTCONN:
+                    self.log.debug("Ignoring socket not connected")
                 else:
                     self.log.debug("Ignoring connection epipe")
         except Exception as e:

gunicorn/workers/sync.py

@@ -146,11 +146,13 @@ def handle(self, listener, client, addr):
                 self.log.debug("Error processing SSL request.")
                 self.handle_error(req, client, addr, e)
         except EnvironmentError as e:
-            if e.errno not in (errno.EPIPE, errno.ECONNRESET):
+            if e.errno not in (errno.EPIPE, errno.ECONNRESET, errno.ENOTCONN):
                 self.log.exception("Socket error processing request.")
             else:
                 if e.errno == errno.ECONNRESET:
                     self.log.debug("Ignoring connection reset")
+                elif e.errno == errno.ENOTCONN:
+                    self.log.debug("Ignoring socket not connected")
                 else:
                     self.log.debug("Ignoring EPIPE")
         except Exception as e: