Changes between Version 1 and Version 2 of TracModPython


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Timestamp:
08/02/11 11:44:45 (7 years ago)
Author:
trac
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  • TracModPython

    v1 v2  
    11= Trac and mod_python = 
    2  
    3 Trac supports [http://www.modpython.org/ mod_python], which speeds up Trac's response times considerably and permits use of many Apache features not possible with [wiki:TracStandalone tracd]/mod_proxy. 
     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 [trac:wiki:TracModPython2.7 TracModPython2.7]. 
     7 
     8== A Word of Warning == 
     9 
     10As of 16^th^ June 2010, the mod_python project is officially dead.  If you are considering using mod_python for a new installation, '''please don't'''!  There are known issues which will not be fixed and there are now better alternatives.  Check out the main TracInstall pages for your target version for more information. 
    411 
    512== Simple configuration == 
     
    1017}}} 
    1118 
     19''Note: The exact path to the module depends on how the HTTPD installation is laid out.'' 
     20 
     21On Debian using apt-get 
     22{{{ 
     23apt-get install libapache2-mod-python libapache2-mod-python-doc 
     24}}} 
     25(Still on Debian) after you have installed mod_python, you must enable the modules in apache2 (equivalent of the above Load Module directive): 
     26{{{ 
     27a2enmod python 
     28}}} 
     29On Fedora use, using yum: 
     30{{{ 
     31yum install mod_python 
     32}}} 
     33You 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+. 
     34{{{ 
     35#!xml 
     36<Location /mpinfo> 
     37   SetHandler mod_python 
     38   PythonInterpreter main_interpreter 
     39   PythonHandler mod_python.testhandler 
     40</Location> 
     41}}} 
     42 
    1243A simple setup of Trac on mod_python looks like this: 
    1344{{{ 
     45#!xml 
    1446<Location /projects/myproject> 
    1547   SetHandler mod_python 
     48   PythonInterpreter main_interpreter 
    1649   PythonHandler trac.web.modpython_frontend  
    1750   PythonOption TracEnv /var/trac/myproject 
     
    2053}}} 
    2154 
    22 Note that the option `TracUriRoot` may or may not be necessary in your setup. Try without first, and if the URLs produced by Trac look wrong or if Trac does not seem to recognize the URLs correctly, add the `TracUriRoot` option. 
    23  
    24 Configuring authentication works the same as for [wiki:TracCgi#AddingAuthentication CGI]: 
    25 {{{ 
    26 <Location "/projects/myproject/login"> 
     55The 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. 
     56 
     57The options available are 
     58{{{ 
     59    # For a single project 
     60    PythonOption TracEnv /var/trac/myproject 
     61    # For multiple projects 
     62    PythonOption TracEnvParentDir /var/trac/myprojects 
     63    # For the index of multiple projects 
     64    PythonOption TracEnvIndexTemplate /srv/www/htdocs/trac/project_list_template.html 
     65    # A space delimitted list, with a "," between key and value pairs. 
     66    PythonOption TracTemplateVars key1,val1 key2,val2 
     67    # Useful to get the date in the wanted order 
     68    PythonOption TracLocale en_GB.UTF8 
     69    # See description above         
     70    PythonOption TracUriRoot /projects/myproject 
     71}}} 
     72 
     73=== Python Egg Cache === 
     74 
     75Compressed python eggs like Genshi are normally extracted into a directory named `.python-eggs` in the users home directory. Since apache's home usually is not writable an alternate egg cache directory can be specified like this: 
     76{{{ 
     77PythonOption PYTHON_EGG_CACHE /var/trac/myprojects/egg-cache 
     78}}} 
     79 
     80or you can uncompress the Genshi egg to resolve problems extracting from it. 
     81=== Configuring Authentication === 
     82 
     83Creating password files and configuring authentication works similar to the process for [wiki:TracCgi#AddingAuthentication CGI]: 
     84{{{ 
     85#!xml 
     86<Location /projects/myproject/login> 
    2787  AuthType Basic 
    2888  AuthName "myproject" 
    29   AuthUserFile /var/trac/myproject/.htaccess 
     89  AuthUserFile /var/trac/myproject/.htpasswd 
    3090  Require valid-user 
    3191</Location> 
    3292}}} 
    3393 
     94Configuration for mod_ldap authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19) 
     95 
     961. You need to load the following modules in Apache httpd.conf 
     97{{{ 
     98LoadModule ldap_module modules/mod_ldap.so 
     99LoadModule authnz_ldap_module modules/mod_authnz_ldap.so 
     100}}} 
     101 
     1022. Your httpd.conf also needs to look something like: 
     103 
     104{{{ 
     105#!xml 
     106<Location /trac/> 
     107  SetHandler mod_python 
     108  PythonInterpreter main_interpreter 
     109  PythonHandler trac.web.modpython_frontend 
     110  PythonOption TracEnv /home/trac/ 
     111  PythonOption TracUriRoot /trac/ 
     112  Order deny,allow 
     113  Deny from all 
     114  Allow from 192.168.11.0/24 
     115  AuthType Basic 
     116  AuthName "Trac" 
     117  AuthBasicProvider "ldap" 
     118  AuthLDAPURL "ldap://127.0.0.1/dc=example,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)" 
     119  authzldapauthoritative Off 
     120  require valid-user 
     121</Location> 
     122}}} 
     123 
     124Or the LDAP interface to a Microsoft Active Directory: 
     125 
     126{{{ 
     127#!xml 
     128<Location /trac/> 
     129  SetHandler mod_python 
     130  PythonInterpreter main_interpreter 
     131  PythonHandler trac.web.modpython_frontend 
     132  PythonOption TracEnv /home/trac/ 
     133  PythonOption TracUriRoot /trac/ 
     134  Order deny,allow 
     135  Deny from all 
     136  Allow from 192.168.11.0/24 
     137  AuthType Basic 
     138  AuthName "Trac" 
     139  AuthBasicProvider "ldap" 
     140  AuthLDAPURL "ldap://adserver.company.com:3268/DC=company,DC=com?sAMAccountName?sub?(objectClass=user)" 
     141  AuthLDAPBindDN       ldap-auth-user@company.com 
     142  AuthLDAPBindPassword "the_password" 
     143  authzldapauthoritative Off 
     144  # require valid-user 
     145  require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com 
     146</Location> 
     147}}} 
     148 
     149Note 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. 
     150 
     151Note 2: Active Directory requires an authenticating user/password to access records (AuthLDAPBindDN and AuthLDAPBindPassword). 
     152 
     153Note 3: The directive "require ldap-group ..."  specifies an AD group whose members are allowed access. 
     154 
     155 
     156=== Setting the Python Egg Cache === 
     157 
     158If the Egg Cache isn't writeable by your Web server, you'll either have to change the permissions, or point Python to a location where Apache can write. This can manifest itself as a ''500 internal server error'' and/or a complaint in the syslog.  
     159 
     160{{{ 
     161#!xml 
     162<Location /projects/myproject> 
     163  ... 
     164  PythonOption PYTHON_EGG_CACHE /tmp  
     165  ... 
     166</Location> 
     167}}} 
     168 
     169 
     170=== Setting the !PythonPath === 
     171 
    34172If 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: 
    35173{{{ 
     174#!xml 
    36175<Location /projects/myproject> 
    37176  ... 
     
    41180}}} 
    42181 
     182Be careful about using the !PythonPath directive, and ''not'' `SetEnv PYTHONPATH`, as the latter won't work. 
    43183 
    44184== Setting up multiple projects == 
    45185 
    46 The Trac mod_python handler handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`: 
    47 {{{ 
     186The Trac mod_python handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`: 
     187{{{ 
     188#!xml 
    48189<Location /projects> 
    49190  SetHandler mod_python 
     191  PythonInterpreter main_interpreter 
    50192  PythonHandler trac.web.modpython_frontend  
    51193  PythonOption TracEnvParentDir /var/trac 
     
    54196}}} 
    55197 
    56 When you request the `/projects` URL, you will get a listing of all subdirectories of the directory you set as `TracEnvParentDir`. Selecting any project in the list will bring you to the corresponding Trac environment. 
     198When 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. 
    57199 
    58200If you don't want to have the subdirectory listing as your projects home page you can use a 
    59201{{{ 
     202#!xml 
    60203<LocationMatch "/.+/"> 
    61204}}} 
     
    65208You can also use the same authentication realm for all of the projects using a `<LocationMatch>` directive: 
    66209{{{ 
    67 <LocationMatch "/[^/]+/login"> 
     210#!xml 
     211<LocationMatch "/projects/[^/]+/login"> 
    68212  AuthType Basic 
    69213  AuthName "Trac" 
    70   AuthUserFile /var/trac/.htaccess 
     214  AuthUserFile /var/trac/.htpasswd 
    71215  Require valid-user 
    72216</LocationMatch> 
     
    79223 
    80224{{{ 
     225#!xml 
    81226<VirtualHost * > 
    82     DocumentRoot /var/trac/myproject 
     227    DocumentRoot /var/www/myproject 
    83228    ServerName trac.mycompany.com 
    84     <Directory /> 
     229    <Location /> 
    85230        SetHandler mod_python 
     231        PythonInterpreter main_interpreter 
    86232        PythonHandler trac.web.modpython_frontend 
    87233        PythonOption TracEnv /var/trac/myproject 
    88234        PythonOption TracUriRoot / 
    89     </Directory> 
     235    </Location> 
    90236    <Location /login> 
    91237        AuthType Basic 
    92238        AuthName "MyCompany Trac Server" 
    93         AuthUserFile /var/trac/myproject/.htusers 
     239        AuthUserFile /var/trac/myproject/.htpasswd 
    94240        Require valid-user 
    95241    </Location> 
     
    97243}}} 
    98244 
     245This does not seem to work in all cases. What you can do if it does not: 
     246 * Try using `<LocationMatch>` instead of `<Location>` 
     247 * <Location /> may, in your server setup, refer to the complete host instead of simple the root of the server. This means that everything (including the login directory referenced below) will be sent to python and authentication does not work (i.e. you get the infamous Authentication information missing error). If this applies to you, try using a sub-directory for trac instead of the root (i.e. /web/ and /web/login instead of / and /login). 
     248 * Depending on apache's `NameVirtualHost` configuration, you may need to use `<VirtualHost *:80>` instead of `<VirtualHost *>`. 
     249 
     250For a virtual host that supports multiple projects replace "`TracEnv`" /var/trac/myproject with "`TracEnvParentDir`" /var/trac/ 
     251 
     252Note: !DocumentRoot should not point to your Trac project env. As Asmodai wrote on #trac: "suppose there's a webserver bug that allows disclosure of !DocumentRoot they could then leech the entire Trac environment". 
     253 
    99254== Troubleshooting == 
    100255 
     256In general, if you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option: 
     257{{{ 
     258#!xml 
     259<Location /projects/myproject> 
     260  ... 
     261  PythonDebug on 
     262</Location> 
     263}}} 
     264 
     265For multiple projects, try restarting the server as well. 
     266 
     267=== Expat-related segmentation faults === #expat 
     268 
     269This problem will most certainly hit you on Unix when using Python 2.4. 
     270In Python 2.4, some version of Expat (an XML parser library written in C) is used,  
     271and if Apache is using another version, this results in segmentation faults. 
     272As Trac 0.11 is using Genshi, which will indirectly use Expat, that problem 
     273can now hit you even if everything was working fine before with Trac 0.10. 
     274 
     275See Graham Dumpleton's detailed [http://www.dscpl.com.au/wiki/ModPython/Articles/ExpatCausingApacheCrash explanation and workarounds] for the issue. 
     276 
    101277=== Form submission problems === 
    102278 
    103279If 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. 
    104280 
     281=== Problem with virtual host configuration === 
     282 
     283If 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). 
     284 
     285Using <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. 
     286 
     287=== Problem with zipped egg === 
     288 
     289It's possible that your version of mod_python will not import modules from zipped eggs. If you encounter an `ImportError: No module named trac` in your Apache logs but you think everything is where it should be, this might be your problem. Look in your site-packages directory; if the Trac module appears as a ''file'' rather than a ''directory'', then this might be your problem. To rectify, try installing Trac using the `--always-unzip` option, like this: 
     290 
     291{{{ 
     292easy_install --always-unzip Trac-0.12b1.zip 
     293}}} 
     294 
    105295=== Using .htaccess === 
    106296 
     
    109299It 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. :) 
    110300 
     301A success story: For me it worked out-of-box, with following trivial config: 
     302{{{ 
     303SetHandler mod_python 
     304PythonInterpreter main_interpreter 
     305PythonHandler trac.web.modpython_frontend  
     306PythonOption TracEnv /system/path/to/this/directory 
     307PythonOption TracUriRoot /path/on/apache 
     308 
     309AuthType Basic 
     310AuthName "ProjectName" 
     311AuthUserFile /path/to/.htpasswd 
     312Require valid-user 
     313}}} 
     314 
     315The `TracUriRoot` is obviously the path you need to enter to the browser to get to the trac (e.g. domain.tld/projects/trac) 
     316 
     317=== Additional .htaccess help === 
     318 
     319If you are using the .htaccess method you may have additional problems if your trac directory is inheriting .htaccess directives from another.  This may also help to add to your .htaccess file: 
     320 
     321{{{ 
     322<IfModule mod_rewrite.c> 
     323  RewriteEngine Off 
     324</IfModule> 
     325}}} 
     326 
     327 
    111328=== Win32 Issues === 
    112  
    113 If you run trac with mod_python (3.1.3 or 3.1.4) on Windows,  
    114 uploading attachments will '''not''' work. 
    115 This is a known problem which we can't solve cleanly at the Trac level. 
    116  
    117 However, there is a workaround for this at the mod_python level,  
    118 which is to apply the following patch [http://projects.edgewall.com/trac/attachment/ticket/554/util_py.patch attachment:ticket:554:util_py.patch]  
    119 to the (Lib/site-packages)/modpython/util.py file. 
    120  
    121 If you don't have the `patch` command, that file can be replaced with the [http://svn.apache.org/viewcvs.cgi/httpd/mod_python/trunk/lib/python/mod_python/util.py?rev=103562&view=markup  fixed util.py] (fix which, although done prior to the 3.1.4 release, is ''not''  
    122 present in 3.1.4). 
     329If 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. 
     330 
    123331 
    124332=== OS X issues === 
     
    126334When 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]. 
    127335 
     336=== SELinux issues === 
     337 
     338If Trac reports something like: ''Cannot get shared lock on db.lock'' 
     339The security context on the repository may need to be set: 
     340 
     341{{{ 
     342chcon -R -h -t httpd_sys_content_t PATH_TO_REPOSITORY 
     343}}} 
     344 
     345See also [http://subversion.tigris.org/faq.html#reposperms] 
     346 
     347=== FreeBSD issues === 
     348Pay 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. 
     349 
     350If 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. 
     351The best option [http://modpython.org/pipermail/mod_python/2006-September/021983.html seems to be] adding to /usr/local/apache2/bin/ennvars the line  
     352 
     353{{{ 
     354export LD_PRELOAD=/usr/lib/libc_r.so 
     355}}} 
     356 
     357=== Subversion issues === 
     358 
     359If 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.) 
     360 
     361If 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`). 
     362 
     363You 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 [trac:#3371 #3371], in order to force the use of the main interpreter: 
     364{{{ 
     365PythonInterpreter main_interpreter 
     366}}} 
     367This is anyway the recommended workaround for other well-known issues seen when using the Python bindings for Subversion within mod_python ([trac:#2611 #2611], [trac:#3455 #3455]). See in particular Graham Dumpleton's comment in [trac:comment:9:ticket:3455 #3455] explaining the issue. 
     368 
     369=== Page layout issues === 
     370 
     371If 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: 
     372{{{ 
     373#!xml 
     374Alias /myproject/css "/usr/share/trac/htdocs/css" 
     375<Location /myproject/css> 
     376    SetHandler None 
     377</Location> 
     378}}} 
     379 
     380Note: For the above configuration to have any effect it must be put after the configuration of your project root location, i.e. {{{<Location /myproject />}}}. 
     381 
     382Also, setting `PythonOptimize On` seems to mess up the page headers and footers, in addition to hiding the documentation for macros and plugins (see #Trac8956). Considering how little effect the option has, it is probably a good idea to leave it `Off`. 
     383 
     384=== HTTPS issues === 
     385 
     386If 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: 
     387{{{ 
     388#!xml 
     389<VirtualHost * > 
     390    DocumentRoot /var/www/myproject 
     391    ServerName trac.mycompany.com 
     392    SetEnv HTTPS 1 
     393    .... 
     394</VirtualHost> 
     395}}} 
     396 
     397=== Fedora 7 Issues === 
     398Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython but not for tracd 
     399 
     400 
     401=== Segmentation fault with php5-mhash or other php5 modules === 
     402You 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] 
     403 
     404Some 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] 
     405 
    128406---- 
    129 See also TracGuide, TracInstall, TracCgi, TracFastCgi 
     407See also:  TracGuide, TracInstall, [wiki:TracModWSGI ModWSGI], [wiki:TracFastCgi FastCGI],  [trac:TracNginxRecipe TracNginxRecipe]