Changes between Initial Version and Version 1 of TracModPython


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Timestamp:
Oct 22, 2008 10:31:47 AM (16 years ago)
Author:
trac
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  • TracModPython

    v1 v1  
     1= Trac and mod_python =
     2[[TracGuideToc]]
     3
     4Trac supports [http://www.modpython.org/ mod_python], which speeds up Trac's response times considerably, especially compared to [TracCgi CGI], and permits use of many Apache features not possible with [wiki:TracStandalone tracd]/mod_proxy.
     5
     6These instructions are for Apache 2; if you are still using Apache 1.3, you may have some luck with [wiki:TracModPython2.7 TracModPython2.7].
     7
     8== Simple configuration ==
     9
     10If you just installed mod_python, you may have to add a line to load the module in the Apache configuration:
     11{{{
     12LoadModule python_module modules/mod_python.so
     13}}}
     14
     15 ''Note: The exact path to the module depends on how the HTTPD installation is laid out.''
     16On Debian using apt-get
     17{{{
     18apt-get install libapache2-mod-python libapache2-mod-python-doc
     19}}}
     20(Still on Debian) after you have installed mod_python, you must enable the modules in apache2 (equivalent of the above Load Module directive):
     21{{{
     22a2enmod mod_python
     23}}}
     24On Fedora use, using yum:
     25{{{
     26yum install mod_python
     27}}}
     28You can test your mod_python installation by adding the following to your httpd.conf.  You should remove this when you are done testing for security reasons. Note: mod_python.testhandler is only available in mod_python 3.2+.
     29{{{
     30#!xml
     31<Location /mpinfo>
     32   SetHandler mod_python
     33   PythonInterpreter main_interpreter
     34   PythonHandler mod_python.testhandler
     35</Location>
     36}}}
     37
     38A simple setup of Trac on mod_python looks like this:
     39{{{
     40#!xml
     41<Location /projects/myproject>
     42   SetHandler mod_python
     43   PythonInterpreter main_interpreter
     44   PythonHandler trac.web.modpython_frontend
     45   PythonOption TracEnv /var/trac/myproject
     46   PythonOption TracUriRoot /projects/myproject
     47</Location>
     48}}}
     49
     50The option '''`TracUriRoot`''' may or may not be necessary in your setup. Try your configuration without it; if the URLs produced by Trac look wrong, if Trac does not seem to recognize URLs correctly, or you get an odd "No handler matched request to..." error, add the '''`TracUriRoot`''' option.  You will notice that the `Location` and '''`TracUriRoot`''' have the same path.
     51
     52=== Configuring Authentication ===
     53
     54Creating password files and configuring authentication works similar to the process for [wiki:TracCgi#AddingAuthentication CGI]:
     55{{{
     56#!xml
     57<Location /projects/myproject/login>
     58  AuthType Basic
     59  AuthName "myproject"
     60  AuthUserFile /var/trac/myproject/.htpasswd
     61  Require valid-user
     62</Location>
     63}}}
     64
     65Configuration for mod_ldap authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19)
     66
     671. You need to load the following modules in Apache httpd.conf
     68{{{
     69LoadModule ldap_module modules/mod_ldap.so
     70LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
     71}}}
     72
     732. Your httpd.conf also needs to look something like:
     74
     75{{{
     76#!xml
     77<Location /trac/>
     78  SetHandler mod_python
     79  PythonInterpreter main_interpreter
     80  PythonHandler trac.web.modpython_frontend
     81  PythonOption TracEnv /home/trac/
     82  PythonOption TracUriRoot /trac/
     83  Order deny,allow
     84  Deny from all
     85  Allow from 192.168.11.0/24
     86  AuthType Basic
     87  AuthName "Trac"
     88  AuthBasicProvider "ldap"
     89  AuthLDAPURL "ldap://127.0.0.1/dc=example,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)"
     90  authzldapauthoritative Off
     91  require valid-user
     92</Location>
     93}}}
     94
     95Or the LDAP interface to a Microsoft Active Directory:
     96
     97{{{
     98#!xml
     99<Location /trac/>
     100  SetHandler mod_python
     101  PythonInterpreter main_interpreter
     102  PythonHandler trac.web.modpython_frontend
     103  PythonOption TracEnv /home/trac/
     104  PythonOption TracUriRoot /trac/
     105  Order deny,allow
     106  Deny from all
     107  Allow from 192.168.11.0/24
     108  AuthType Basic
     109  AuthName "Trac"
     110  AuthBasicProvider "ldap"
     111  AuthLDAPURL "ldap://adserver.company.com:3268/DC=company,DC=com?sAMAccountName?sub?(objectClass=user)"
     112  AuthLDAPBindDN       ldap-auth-user@company.com
     113  AuthLDAPBindPassword "the_password"
     114  authzldapauthoritative Off
     115  # require valid-user
     116  require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com
     117</Location>
     118}}}
     119
     120Note 1: This is the case where the LDAP search will get around the multiple OUs, conecting to Global Catalog Server portion of AD (Notice the port is 3268, not the normal LDAP 389). The GCS is basically a "flattened" tree which allows searching for a user without knowing to which OU they belong.
     121
     122Note 2: Active Directory requires an authenticating user/password to access records (AuthLDAPBindDN and AuthLDAPBindPassword).
     123
     124Note 3: The directive "require ldap-group ..."  specifies an AD group whose members are allowed access.
     125
     126
     127
     128=== Setting the !PythonPath ===
     129
     130If the Trac installation isn't installed in your Python path, you'll have to tell Apache where to find the Trac mod_python handler  using the `PythonPath` directive:
     131{{{
     132#!xml
     133<Location /projects/myproject>
     134  ...
     135  PythonPath "sys.path + ['/path/to/trac']"
     136  ...
     137</Location>
     138}}}
     139
     140Be careful about using the !PythonPath directive, and ''not'' `SetEnv PYTHONPATH`, as the latter won't work.
     141
     142== Setting up multiple projects ==
     143
     144The Trac mod_python handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`:
     145{{{
     146#!xml
     147<Location /projects>
     148  SetHandler mod_python
     149  PythonInterpreter main_interpreter
     150  PythonHandler trac.web.modpython_frontend
     151  PythonOption TracEnvParentDir /var/trac
     152  PythonOption TracUriRoot /projects
     153</Location>
     154}}}
     155
     156When you request the `/projects` URL, you will get a listing of all subdirectories of the directory you set as `TracEnvParentDir` that look like Trac environment directories. Selecting any project in the list will bring you to the corresponding Trac environment.
     157
     158If you don't want to have the subdirectory listing as your projects home page you can use a
     159{{{
     160#!xml
     161<LocationMatch "/.+/">
     162}}}
     163
     164This will instruct Apache to use mod_python for all locations different from root while having the possibility of placing a custom home page for root in your !DocumentRoot folder.
     165
     166You can also use the same authentication realm for all of the projects using a `<LocationMatch>` directive:
     167{{{
     168#!xml
     169<LocationMatch "/projects/[^/]+/login">
     170  AuthType Basic
     171  AuthName "Trac"
     172  AuthUserFile /var/trac/.htpasswd
     173  Require valid-user
     174</LocationMatch>
     175}}}
     176
     177== Virtual Host Configuration ==
     178
     179Below is the sample configuration required to set up your trac as a virtual server (i.e. when you access it at the URLs like
     180!http://trac.mycompany.com):
     181
     182{{{
     183#!xml
     184<VirtualHost * >
     185    DocumentRoot /var/www/myproject
     186    ServerName trac.mycompany.com
     187    <Location />
     188        SetHandler mod_python
     189        PythonInterpreter main_interpreter
     190        PythonHandler trac.web.modpython_frontend
     191        PythonOption TracEnv /var/trac/myproject
     192        PythonOption TracUriRoot /
     193    </Location>
     194    <Location /login>
     195        AuthType Basic
     196        AuthName "MyCompany Trac Server"
     197        AuthUserFile /var/trac/myproject/.htpasswd
     198        Require valid-user
     199    </Location>
     200</VirtualHost>
     201}}}
     202
     203if you have issues with login try using `<LocationMatch>` instead of `<Location>`
     204
     205For a virtual host that supports multiple projects replace "`TracEnv`" /var/trac/myproject with "`TracEnvParentDir`" /var/trac/
     206
     207== Troubleshooting ==
     208
     209In general, if you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option:
     210{{{
     211#!xml
     212<Location /projects/myproject>
     213  ...
     214  PythonDebug on
     215</Location>
     216}}}
     217
     218For multiple projects, try restarting the server as well.
     219
     220=== Expat-related segmentation faults === #expat
     221
     222This problem will most certainly hit you on Unix when using python 2.4.
     223In Python 2.4, some version of Expat (an XML parser library written in C) is used,
     224and if Apache is using another version, this results in segmentation faults.
     225As Trac 0.11 is using Genshi, which will use indirectly use Expat, that problem
     226can now hit you even if everything was working fine before with Trac 0.10.
     227
     228See Graham Dumpleton's detailed [http://www.dscpl.com.au/wiki/ModPython/Articles/ExpatCausingApacheCrash explanation and workarounds] for the issue.
     229
     230=== Form submission problems ===
     231
     232If you're experiencing problems submitting some of the forms in Trac (a common problem is that you get redirected to the start page after submission), check whether your {{{DocumentRoot}}} contains a folder or file with the same path that you mapped the mod_python handler to. For some reason, mod_python gets confused when it is mapped to a location that also matches a static resource.
     233
     234=== Problem with virtual host configuration ===
     235
     236If the <Location /> directive is used, setting the `DocumentRoot` may result in a ''403 (Forbidden)'' error. Either remove the `DocumentRoot` directive, or make sure that accessing the directory it points is allowed (in a corresponding `<Directory>` block).
     237
     238Using <Location /> together with `SetHandler` resulted in having everything handled by mod_python, which leads to not being able download any CSS or images/icons. I used <Location /trac> `SetHandler None` </Location> to circumvent the problem, though I do not know if this is the most elegant solution.
     239
     240=== Using .htaccess ===
     241
     242Although it may seem trivial to rewrite the above configuration as a directory in your document root with a `.htaccess` file, this does not work. Apache will append a "/" to any Trac URLs, which interferes with its correct operation.
     243
     244It may be possible to work around this with mod_rewrite, but I failed to get this working. In all, it is more hassle than it is worth. Stick to the provided instructions. :)
     245
     246=== Win32 Issues ===
     247If you run trac with mod_python < 3.2 on Windows, uploading attachments will '''not''' work. This problem is resolved in mod_python 3.1.4 or later, so please upgrade mod_python to fix this.
     248
     249
     250=== OS X issues ===
     251
     252When using mod_python on OS X you will not be able to restart Apache using `apachectl restart`. This is apparently fixed in mod_python 3.2, but there's also a patch available for earlier versions [http://www.dscpl.com.au/projects/vampire/patches.html here].
     253
     254=== SELinux issues ===
     255
     256If Trac reports something like: ''Cannot get shared lock on db.lock''
     257The security context on the repository may need to be set:
     258
     259{{{
     260chcon -R -h -t httpd_sys_content_t PATH_TO_REPOSITORY
     261}}}
     262
     263See also [[http://subversion.tigris.org/faq.html#reposperms]]
     264
     265=== FreeBSD issues ===
     266Pay attention to the version of the installed mod_python and sqlite packages. Ports have both the new and old ones, but earlier versions of pysqlite and mod_python won't integrate as the former requires threaded support in python, and the latter requires a threadless install.
     267
     268If you compiled and installed apache2, apache wouldn´t support threads (cause it doesn´t work very well on FreeBSD). You could force thread support when running ./configure for apache, using --enable-threads, but this isn´t recomendable.
     269The best option [[http://modpython.org/pipermail/mod_python/2006-September/021983.html seems to be]] adding to /usr/local/apache2/bin/ennvars the line
     270
     271{{{
     272export LD_PRELOAD=/usr/lib/libc_r.so
     273}}}
     274
     275=== Subversion issues ===
     276
     277If you get the following Trac Error `Unsupported version control system "svn"` only under mod_python, though it works well on the command-line and even with TracStandalone, chances are that you forgot to add the path to the Python bindings with the [TracModPython#ConfiguringPythonPath PythonPath] directive. (The better way is to add a link to the bindings in the Python `site-packages` directory, or create a `.pth` file in that directory.)
     278
     279If this is not the case, it's possible that you're using Subversion libraries that are binary incompatible with the apache ones (an incompatibility of the `apr` libraries is usually the cause). In that case, you also won't be able to use the svn modules for Apache (`mod_dav_svn`).
     280
     281You also need a recent version of `mod_python` in order to avoid a runtime error ({{{argument number 2: a 'apr_pool_t *' is expected}}}) due to the default usage of multiple sub-interpreters. 3.2.8 ''should'' work, though it's probably better to use the workaround described in #3371, in order to force the use of the main interpreter:
     282{{{
     283PythonInterpreter main_interpreter
     284}}}
     285This is anyway the recommended workaround for other well-known issues seen when using the Python bindings for Subversion within mod_python (#2611, #3455). See in particular Graham Dumpleton's comment in [comment:ticket:3455:9 #3455] explaining the issue.
     286
     287=== Page layout issues ===
     288
     289If the formatting of the Trac pages look weird chances are that the style sheets governing the page layout are not handled properly by the web server. Try adding the following lines to your apache configuration:
     290{{{
     291#!xml
     292Alias /myproject/css "/usr/share/trac/htdocs/css"
     293<Location /myproject/css>
     294    SetHandler None
     295</Location>
     296}}}
     297
     298Note: For the above configuration to have any effect it must be put after the configuration of your project root location, i.e. {{{<Location /myproject />}}}.
     299
     300=== HTTPS issues ===
     301
     302If you want to run Trac fully under https you might find that it tries to redirect to plain http. In this case just add the following line to your apache configuration:
     303{{{
     304#!xml
     305<VirtualHost * >
     306    DocumentRoot /var/www/myproject
     307    ServerName trac.mycompany.com
     308    SetEnv HTTPS 1
     309    ....
     310</VirtualHost>
     311}}}
     312
     313=== Fedora 7 Issues ===
     314Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython but not for tracd
     315
     316
     317=== Segmentation fault with php5-mhash or other php5 modules ===
     318You may encounter segfaults (reported on debian etch) if php5-mhash module is installed. Try to remove it to see if this solves the problem. See debian bug report [[http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=411487]]
     319
     320Some people also have troubles when using php5 compiled with its own 3rd party libraries instead of system libraries. Check here [[http://www.djangoproject.com/documentation/modpython/#if-you-get-a-segmentation-fault]]
     321
     322----
     323See also TracGuide, TracInstall, TracCgi, TracFastCgi