User friendly error message when port is busy

[anatoly techtonik <techtonik@…>]

tracd outputs a non-friendly error message when a port it is trying to bind is busy.

Traceback (most recent call last):
  File "C:\~env\Python27\lib\runpy.py", line 162, in _run_module_as_main
    "__main__", fname, loader, pkg_name)
  File "C:\~env\Python27\lib\runpy.py", line 72, in _run_code
    exec code in run_globals
  File "c:\users\user\appdata\local\temp\easy_install-iylw6e\Trac-0.12-py2.7-win32.egg.tmp\trac\web\standalone.py", line 299, in <module>
  File "c:\users\user\appdata\local\temp\easy_install-iylw6e\Trac-0.12-py2.7-win32.egg.tmp\trac\web\standalone.py", line 290, in main
  File "c:\users\user\appdata\local\temp\easy_install-iylw6e\Trac-0.12-py2.7-win32.egg.tmp\trac\web\standalone.py", line 257, in serve
  File "c:\users\user\appdata\local\temp\easy_install-iylw6e\Trac-0.12-py2.7-win32.egg.tmp\trac\web\standalone.py", line 109, in __init__
  File "c:\users\user\appdata\local\temp\easy_install-iylw6e\Trac-0.12-py2.7-win32.egg.tmp\trac\web\wsgi.py", line 231, in __init__
  File "C:\~env\Python27\lib\SocketServer.py", line 408, in __init__
    self.server_bind()
  File "C:\~env\Python27\lib\BaseHTTPServer.py", line 108, in server_bind
    SocketServer.TCPServer.server_bind(self)
  File "C:\~env\Python27\lib\SocketServer.py", line 419, in server_bind
    self.socket.bind(self.server_address)
  File "C:\~env\Python27\lib\socket.py", line 222, in meth
    return getattr(self._sock,name)(*args)
socket.error: [Errno 10013] An attempt was made to access a socket in a way forbidden by its access permissions

This can be improved to output something like Error starting Trac server on port %s. It may even attempt to connect to detect if there is an existing service already and it is not Trac. And output something like Some application is already running on that port.

Official reasons for the error code
​http://msdn.microsoft.com/en-us/library/ms740668%28VS.85%29.aspx#winsock.wsaeacces_2

[rblank]

I wouldn't go as far as connecting and seeing what's running there, but a better error message would be nice indeed.

[Thijs Triemstra <lists@…>]

This patch prints out the error message but also needs to stop the server, sys.exit(1) doesn't seem to work.

Error starting Trac server on 0.0.0.0:80 view at http://127.0.0.1:80/trac
Permission denied

trac/web/standalone.py

@@ -22 +22 @@
 import pkg_resources
 import os
 import sys
+import socket
 from SocketServer import ThreadingMixIn
 
 from trac import __version__ as VERSION
@@ -241 +242 @@
 
     if options.protocol == 'http':
         def serve():
-            httpd = TracHTTPServer(server_address, wsgi_app,
-                                   options.env_parent_dir, args,
-                                   use_http_11=options.http11)
-
-            print 'Server starting in PID %i.' % os.getpid()
             addr, port = server_address
             if not addr or addr == '0.0.0.0':
-                print 'Serving on 0.0.0.0:%s view at http://127.0.0.1:%s/%s' \
+                loc = '0.0.0.0:%s view at http://127.0.0.1:%s/%s' \
                        % (port, port, base_path)
             else:
-                print 'Serving on http://%s:%s/%s' % (addr, port, base_path)
+                loc = 'http://%s:%s/%s' % (addr, port, base_path)
+
+            try:
+                httpd = TracHTTPServer(server_address, wsgi_app,
+                                       options.env_parent_dir, args,
+                                       use_http_11=options.http11)
+            except socket.error, e:
+                print 'Error starting Trac server on %s' % loc
+                print e.strerror
+                sys.exit(1)
+
+            print 'Server starting in PID %i.' % os.getpid()
+            print 'Serving on %s' % loc
             if options.http11:
                 print 'Using HTTP/1.1 protocol version'
             httpd.serve_forever()

[rblank]

Your patch works great. The reason it doesn't exit correctly is an interference with the auto-reload mechanism, if you use it (it exits fine if you don't use auto-reload). I have a fix for that.

[rblank]

Patch applied in [10316], together with a fix to the auto-reload mechanism so that it exists correctly when the server quits.

[Thijs Triemstra <lists@…>]

Sorry but I just noticed my patch was applied so changing the owner if that's ok.

[rblank]

Oops, yes, sorry for the confusion.

[anatoly techtonik <techtonik@…>]

I still get credits in the SVN log. :P