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Changes between Initial Version and Version 1 of TracModPython

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02/23/08 22:54:25 (10 years ago)
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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