Update 2008Feb11:
From rather obscure comment from 'apt-cache show python-flup' on a Debian system, I discovered that flup has been superseded by
http://www.modwsgi.org/. It is probably worth checking out mod_wsgi instead of mod_fcgid for Python web applications. Based on the documentation for
mod_wsgi integration with Django, I am planning on switching. I will post my results in a future post.
Required Software
mod_fcgid
Download Source and Install
For reference, here is the mod_fcgid INSTALL.txt... see my Mac OS X notes below it for changes required to get it working on Mac OS X 10.5 (Leopard):
NOTE: This module is for Apache2 ONLY
UNIX
It's tested on my RedHat8 and Solaris. But it should work on other *NIX platform.
NOTE: This module MUST run on share memory supported system
1. If your Apache2 installation isn't in /usr/local/apache2, please edit Makefile and correct it
2. cd $mod_fcgid_dir
3. make //in Mac you need Xcode tools, optional install on Install CD
4. make install
5. add the following line in httpd.conf
LoadModule fcgid_module modules/mod_fcgid.so
MAC OS X Notes
- In Mac OS X Leopard, the Makefile needs to be changed from /usr/local/apache2 to /usr/share/httpd, then steps 3 and 4 above should work.
- Step 4 requires: sudo make install
- Step 5, you need to add the following to /etc/apache2/httpd.conf: LoadModule fcgid_module libexec/apache2/mod_fcgid.so
- IMPORTANT: apache 2 on Mac OS X Leopard is 64-bit and by default, the make file does not build the 64-bit module. To do this, you need to add the following to the Makefile after the EXTRA_CFLAGS option (too far above that will cause it not to work apparently):
CFLAGS = -arch ppc -arch ppc64 -arch i386 -arch x86_64
The above will make a universal binary for all Mac OS X.
If at some point, you get this message either in the error_log or by running 'apachectl configtest'
httpd: Syntax error on line 117 of /private/etc/apache2/httpd.conf: Cannot load
/usr/libexec/apache2/mod_fcgid.so into server:
dlopen(/usr/libexec/apache2/mod_fcgid.so, 10): no suitable image found.
Did find: /usr/libexec/apache2/mod_fcgid.so: mach-o, but wrong architecture
Then your mod_fcgid.so module probably was not built with x86_64 architecture... To check, type
file /usr/libexec/apache2/mod_fcgid.so
And it should list the architectures that the mod_fcgid.so was built for.
Enable mod_fcgid
Linux
At least with Debian/Ubuntu you can enable fcgid by typing (as root):
a2enmod fcgid
Mac OS X Leopard (10.5)
Add the following to /etc/apache2/httpd.conf:
AddHandler fcgid-script .fcgi
SocketPath /tmp/fcgid_sock
SharememPath /tmp/fcgid_shm
IPCConnectTimeout 20
mod_rewrite
We need to tell apache for what urls it should pass off the request to the fcgi script. This is accomplished with mod_rewrite which is normally turned on by default w/ apache 2 (at least the installations I have seen).
We'll start with the full setup required for gaworkflow.frontend, but test it with a "Hello World" style dispatch.fcgi script.
gaworkflow.frontend apache2 mod_rewrite setup
Linux
Add the following to your apache2 /etc/apache2/sites-available/default or other vhost specific file:
# Enable access to the django admin media
Alias /media /usr/lib/python2.5/site-packages/django/contrib/admin/media
# Turn on the rewrite engine
RewriteEngine on
# Enable http:///admin/ and related urls
RewriteRule ^/admin(.*)$ /usr/lib/cgi-bin/dispatch.fcgi/admin$1 [QSA,L]
RewriteRule ^/logout(.*)$ /usr/lib/cgi-bin/dispatch.fcgi/logout$1 [QSA,L]
RewriteRule ^/login(.*)$ /usr/lib/cgi-bin/dispatch.fcgi/login$1 [QSA,L]
Mac OS X Leopard
Add the following to your apache2 /etc/httpd.conf:
# Enable access to the django admin media
# NOTE: the following did not work for me... I had to copy the media directory to
# /Library/WebServer/Documents/media
#Alias /media /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/django/contrib/admin/media/
# Turn on the rewrite engine
RewriteEngine on
# Enable http:///admin urls
RewriteRule ^/eland_config(.*)$ /Library/WebServer/CGI-Executables/dispatch.fcgi/eland_config$1 [QSA,L]
RewriteRule ^/admin(.*)$ /Library/WebServer/CGI-Executables/dispatch.fcgi/admin$1 [QSA,L]
RewriteRule ^/logout(.*)$ /Library/WebServer/CGI-Executables/dispatch.fcgi/logout$1 [QSA,L]
RewriteRule ^/login(.*)$ /Library/WebServer/CGI-Executables/dispatch.fcgi/login$1 [QSA,L]
Restart Apache 2
Linux (Debian/Ubuntu)
sudo /etc/init.d/apache2 restart
Mac OS X Leopard
sudo apachectl restart
dispatch.fcgi
Hello World Test
Now to test that we have the mod_fcgid setup properly, create a file called dispatch.fcgi:
#!/usr/bin/python
def myapp(environ, start_response):
start_response('200 OK', [('Content-Type', 'text/plain')])
return ['Hello World!\n']
if __name__ == '__main__':
from flup.server.fcgi import WSGIServer
WSGIServer(myapp).run()
And move it to your cgi-bin directory:
Linux cgi-bin
sudo mv dispatch.fcgi /usr/lib/cgi-bin/
Mac OS X Leopard cgi-bin
sudo mv dispatch.fcgi /Library/WebServer/CGI-Executables/
Linux/Mac OS X File Permissions
sudo chmod a+x /dispatch.fcgi
Mac OS X 10.5 users will need to update the Options for to include +ExecCGI... by default it is set to "Options None". The updated entry should look like:
AllowOverride None
Options +ExecCGI
Order allow,deny
Allow from all
WARNING: You will get a message saying "Forbidden" in the web browser if you do not update the directive above.
Web Browser Test
Point your web browser to http://localhost/admin/ and you should see if it prints "Hello World!". If you see "Hello World!" continue to the next section.
Installing the Django App dispatch.fcgi script
copy of mydjangoapp code
Make a copy of the mydjangoapp code and database and put it in a location that will be the "live" version of the code/database. On Mac OS X, I choose /Library/WebServer/mydjangoapp. Initialize the database like your normally would, but you will need to update the settings.py module so that DATABASE_NAME is an absolute path, otherwise you will get errors in the apache 2 error_log saying that the python code could not connect to the database. Assuming you also choose /Library/WebServer/mydjangoapp, your DATABASE_NAME variable in settings.py should be:
DATABASE_NAME = '/Library/WebServer/mydjangoapp/mydjangoapp.db'
You will also need to update the settings.py TEMPLATE_DIRS to be an absolute path (relative paths don't work for some reason) of "/Library/WebServer/gaworkflow/templates"... so the update version should look like:
TEMPLATE_DIRS = (
"/Library/WebServer/mydjangoapp/templates",
)
Also, you will need to make a link to the admin templates in our /Library/WebServer/mydjangoapp/templates directory by typing:
Mac OS X 10.5:
ln -s /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/django/contrib/admin/templates/admin /Library/WebServer/mydjangoapp/templates/admin
ln -s /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/django/contrib/admin/templates/admin_doc /Library/WebServer/mydjangoapp/templates/admin_doc
ln -s /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/django/contrib/admin/templates/widget /Library/WebServer/mydjangoapp/templates/widget
ln -s /System/Library/Frameworks/Python.framework/Versions/2.5/lib/python2.5/site-packages/django/contrib/admin/templates/registration /Library/WebServer/mydjangoapp/templates/registration
Warning: The following directions will tell you how to get past the db read/access errors but may not be the best choice for security... you consider the possible security issues before following the following instructions.
To get the dispatch.fcgi to work properly, I needed to change ownership of /Library/WebServer/mydjangoapp to be owned by the apache2 user, which is _www on Mac OS X 10.5 and www-data on Debian/Ubuntu systems. The the apache user also needs access to the mydjangoapp.db as well. I ran the following commands on Mac OS X 10.5 when placing the files in /Library/WebServer/gaworkflow:
sudo chown _www:_www /Library/WebServer/mydjangoapp
sudo chown _www:_www /Library/WebServer/mydjangoapp/mydjangoapp.db
sudo chmod o-rwx /Library/WebServer/mydjangoapp/mydjangoapp.db
sudo chmod ug+rwx /Library/WebServer/mydjangoapp/mydjangoapp.db
new dispatch.fcgi ΒΆ
Replace the hello world dispatch.fcgi with the following script:
#!/usr/bin/python
import sys
sys.path += ['/Library/WebServer/mydjangoapp']
from flup.server.fcgi import WSGIServer
from django.core.handlers.wsgi import WSGIHandler
import os
os.environ['DJANGO_SETTINGS_MODULE'] = 'mydjangoapp.settings'
WSGIServer(WSGIHandler()).run()
You will need to update these two rows:
- sys.path += ['/Library/WebServer/mydjangoapp']
- os.environ['DJANGO_SETTINGS_MODULE'] = 'mydjangoapp.settings'
Where '/Library/WebServer/gaworkflow should be replaced by PYTHONPATH that would allow your Django package to be imported... one directory level below the directory containing init.py.
NOTE: Make sure you dispatch.fcgi is executable:
sudo chmod a+x dispatch.fcgi
If everything worked out properly, you should have a working installation of gaworkflow.frontend using mod_fcgid.
Trouble Shooting
- Check apache error logs.
- run: sudo apachectl configtest
- Check that dispatch.fcgi has #!/usr/bin/python and not #!/usr/bin/env python as that will screw up the environment variables at least w/ Apache 2 that ships on Mac OS 10.5.
- run 'python dispatch.fcgi' to see if you get any standard Python errors.
Apache2 - error_log -- [warn] mod_fcgid: stderr: OperationalError: unable to open database file
This means the database is not accessible by the user that is running apache. On Mac OS X 10.5, the user is _www. On Debian/Ubuntu Linux the user is www-data. See the "copy of gaworkflow code" section above for directions on changing file permissions for the database.
