Changes between Initial Version and Version 1 of TracModPython

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06/27/11 21:30:57 (3 years ago)
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trac (IP: 127.0.0.1)
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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 
     52The options available are 
     53{{{ 
     54    # For a single project 
     55    PythonOption TracEnv /var/trac/myproject 
     56    # For multiple projects 
     57    PythonOption TracEnvParentDir /var/trac/myprojects 
     58    # For the index of multiple projects 
     59    PythonOption TracEnvIndexTemplate /srv/www/htdocs/trac/project_list_tepmlate.html 
     60    # A space delimitted list, with a "," between key and value pairs. 
     61    PythonOption TracTemplateVars key1,val1 key2,val2 
     62    # Useful to get the date in the wanted order 
     63    PythonOption TracLocale en_GB.UTF8 
     64    # See description above         
     65    PythonOption TracUriRoot /projects/myproject 
     66    # Override default python egg cache location 
     67    PythonOption PYTHON_EGG_CACHE /var/trac/myprojects/egg-cache 
     68}}} 
     69 
     70=== Configuring Authentication === 
     71 
     72Creating password files and configuring authentication works similar to the process for [wiki:TracCgi#AddingAuthentication CGI]: 
     73{{{ 
     74#!xml 
     75<Location /projects/myproject/login> 
     76  AuthType Basic 
     77  AuthName "myproject" 
     78  AuthUserFile /var/trac/myproject/.htpasswd 
     79  Require valid-user 
     80</Location> 
     81}}} 
     82 
     83Configuration for mod_ldap authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19) 
     84 
     851. You need to load the following modules in Apache httpd.conf 
     86{{{ 
     87LoadModule ldap_module modules/mod_ldap.so 
     88LoadModule authnz_ldap_module modules/mod_authnz_ldap.so 
     89}}} 
     90 
     912. Your httpd.conf also needs to look something like: 
     92 
     93{{{ 
     94#!xml 
     95<Location /trac/> 
     96  SetHandler mod_python 
     97  PythonInterpreter main_interpreter 
     98  PythonHandler trac.web.modpython_frontend 
     99  PythonOption TracEnv /home/trac/ 
     100  PythonOption TracUriRoot /trac/ 
     101  Order deny,allow 
     102  Deny from all 
     103  Allow from 192.168.11.0/24 
     104  AuthType Basic 
     105  AuthName "Trac" 
     106  AuthBasicProvider "ldap" 
     107  AuthLDAPURL "ldap://127.0.0.1/dc=example,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)" 
     108  authzldapauthoritative Off 
     109  require valid-user 
     110</Location> 
     111}}} 
     112 
     113Or the LDAP interface to a Microsoft Active Directory: 
     114 
     115{{{ 
     116#!xml 
     117<Location /trac/> 
     118  SetHandler mod_python 
     119  PythonInterpreter main_interpreter 
     120  PythonHandler trac.web.modpython_frontend 
     121  PythonOption TracEnv /home/trac/ 
     122  PythonOption TracUriRoot /trac/ 
     123  Order deny,allow 
     124  Deny from all 
     125  Allow from 192.168.11.0/24 
     126  AuthType Basic 
     127  AuthName "Trac" 
     128  AuthBasicProvider "ldap" 
     129  AuthLDAPURL "ldap://adserver.company.com:3268/DC=company,DC=com?sAMAccountName?sub?(objectClass=user)" 
     130  AuthLDAPBindDN       ldap-auth-user@company.com 
     131  AuthLDAPBindPassword "the_password" 
     132  authzldapauthoritative Off 
     133  # require valid-user 
     134  require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com 
     135</Location> 
     136}}} 
     137 
     138Note 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. 
     139 
     140Note 2: Active Directory requires an authenticating user/password to access records (AuthLDAPBindDN and AuthLDAPBindPassword). 
     141 
     142Note 3: The directive "require ldap-group ..."  specifies an AD group whose members are allowed access. 
     143 
     144 
     145 
     146=== Setting the !PythonPath === 
     147 
     148If 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: 
     149{{{ 
     150#!xml 
     151<Location /projects/myproject> 
     152  ... 
     153  PythonPath "sys.path + ['/path/to/trac']" 
     154  ... 
     155</Location> 
     156}}} 
     157 
     158Be careful about using the !PythonPath directive, and ''not'' `SetEnv PYTHONPATH`, as the latter won't work. 
     159 
     160== Setting up multiple projects == 
     161 
     162The Trac mod_python handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`: 
     163{{{ 
     164#!xml 
     165<Location /projects> 
     166  SetHandler mod_python 
     167  PythonInterpreter main_interpreter 
     168  PythonHandler trac.web.modpython_frontend  
     169  PythonOption TracEnvParentDir /var/trac 
     170  PythonOption TracUriRoot /projects 
     171</Location> 
     172}}} 
     173 
     174When 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. 
     175 
     176If you don't want to have the subdirectory listing as your projects home page you can use a 
     177{{{ 
     178#!xml 
     179<LocationMatch "/.+/"> 
     180}}} 
     181 
     182This 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. 
     183 
     184You can also use the same authentication realm for all of the projects using a `<LocationMatch>` directive: 
     185{{{ 
     186#!xml 
     187<LocationMatch "/projects/[^/]+/login"> 
     188  AuthType Basic 
     189  AuthName "Trac" 
     190  AuthUserFile /var/trac/.htpasswd 
     191  Require valid-user 
     192</LocationMatch> 
     193}}} 
     194 
     195== Virtual Host Configuration == 
     196 
     197Below is the sample configuration required to set up your trac as a virtual server (i.e. when you access it at the URLs like 
     198!http://trac.mycompany.com): 
     199 
     200{{{ 
     201#!xml 
     202<VirtualHost * > 
     203    DocumentRoot /var/www/myproject 
     204    ServerName trac.mycompany.com 
     205    <Location /> 
     206        SetHandler mod_python 
     207        PythonInterpreter main_interpreter 
     208        PythonHandler trac.web.modpython_frontend 
     209        PythonOption TracEnv /var/trac/myproject 
     210        PythonOption TracUriRoot / 
     211    </Location> 
     212    <Location /login> 
     213        AuthType Basic 
     214        AuthName "MyCompany Trac Server" 
     215        AuthUserFile /var/trac/myproject/.htpasswd 
     216        Require valid-user 
     217    </Location> 
     218</VirtualHost> 
     219}}} 
     220 
     221if you have issues with login try using `<LocationMatch>` instead of `<Location>` 
     222 
     223For a virtual host that supports multiple projects replace "`TracEnv`" /var/trac/myproject with "`TracEnvParentDir`" /var/trac/ 
     224 
     225Note: !DocumentRoot should not point to your Trac project env. As Asmodai wrote on #trac: "suppose there's a webserer bug that allows disclosure of !DocumentRoot they could then leech the entire Trac environment". 
     226 
     227== Troubleshooting == 
     228 
     229In general, if you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option: 
     230{{{ 
     231#!xml 
     232<Location /projects/myproject> 
     233  ... 
     234  PythonDebug on 
     235</Location> 
     236}}} 
     237 
     238For multiple projects, try restarting the server as well. 
     239 
     240=== Expat-related segmentation faults === #expat 
     241 
     242This problem will most certainly hit you on Unix when using Python 2.4. 
     243In Python 2.4, some version of Expat (an XML parser library written in C) is used,  
     244and if Apache is using another version, this results in segmentation faults. 
     245As Trac 0.11 is using Genshi, which will indirectly use Expat, that problem 
     246can now hit you even if everything was working fine before with Trac 0.10. 
     247 
     248See Graham Dumpleton's detailed [http://www.dscpl.com.au/wiki/ModPython/Articles/ExpatCausingApacheCrash explanation and workarounds] for the issue. 
     249 
     250=== Form submission problems === 
     251 
     252If 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. 
     253 
     254=== Problem with virtual host configuration === 
     255 
     256If 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). 
     257 
     258Using <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. 
     259 
     260=== Using .htaccess === 
     261 
     262Although 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. 
     263 
     264It 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. :) 
     265 
     266=== Win32 Issues === 
     267If 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. 
     268 
     269 
     270=== OS X issues === 
     271 
     272When 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]. 
     273 
     274=== SELinux issues === 
     275 
     276If Trac reports something like: ''Cannot get shared lock on db.lock'' 
     277The security context on the repository may need to be set: 
     278 
     279{{{ 
     280chcon -R -h -t httpd_sys_content_t PATH_TO_REPOSITORY 
     281}}} 
     282 
     283See also [[http://subversion.tigris.org/faq.html#reposperms]] 
     284 
     285=== FreeBSD issues === 
     286Pay 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. 
     287 
     288If 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 recommendable. 
     289The best option [[http://modpython.org/pipermail/mod_python/2006-September/021983.html seems to be]] adding to /usr/local/apache2/bin/ennvars the line  
     290 
     291{{{ 
     292export LD_PRELOAD=/usr/lib/libc_r.so 
     293}}} 
     294 
     295=== Subversion issues === 
     296 
     297If 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.) 
     298 
     299If 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`). 
     300 
     301You 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: 
     302{{{ 
     303PythonInterpreter main_interpreter 
     304}}} 
     305This 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. 
     306 
     307=== Page layout issues === 
     308 
     309If 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: 
     310{{{ 
     311#!xml 
     312Alias /myproject/css "/usr/share/trac/htdocs/css" 
     313<Location /myproject/css> 
     314    SetHandler None 
     315</Location> 
     316}}} 
     317 
     318Note: For the above configuration to have any effect it must be put after the configuration of your project root location, i.e. {{{<Location /myproject />}}}. 
     319 
     320=== HTTPS issues === 
     321 
     322If 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: 
     323{{{ 
     324#!xml 
     325<VirtualHost * > 
     326    DocumentRoot /var/www/myproject 
     327    ServerName trac.mycompany.com 
     328    SetEnv HTTPS 1 
     329    .... 
     330</VirtualHost> 
     331}}} 
     332 
     333=== Fedora 7 Issues === 
     334Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython but not for tracd 
     335 
     336 
     337=== Segmentation fault with php5-mhash or other php5 modules === 
     338You 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]] 
     339 
     340Some 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]] 
     341 
     342---- 
     343See also TracGuide, TracInstall, TracCgi, TracFastCgi