Changes between Version 6 and Version 7 of TracModPython


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Timestamp:
03/24/15 23:15:03 (2 years ago)
Author:
trac
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  • TracModPython

    v6 v7  
    1 = Trac and mod_python
     1= Trac and mod_python =
    22[[TracGuideToc]]
    33
    4 Mod_python is an [https://httpd.apache.org/ Apache] module that embeds the Python interpreter within the server, so that web-based applications in Python will run many times faster than traditional CGI and will have the ability to retain database connections.
    54Trac 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.
    65
    7 These instructions are for Apache 2. If you are using Apache 1.3, you may have some luck with [trac:wiki:TracModPython2.7 TracModPython2.7], but that is a deprecated setup.
     6{{{#!div class="important"
     7** A Word of Warning **
     8
     9As 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.
     10}}}
     11
     12
     13These 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], but you'll be totally on your own.
    814
    915[[PageOutline(2-3,Overview,inline)]]
     
    1824''Note: The exact path to the module depends on how the HTTPD installation is laid out.''
    1925
    20 On Debian using apt-get:
     26On Debian using apt-get
    2127{{{
    2228apt-get install libapache2-mod-python libapache2-mod-python-doc
    2329}}}
    24 Still on Debian, after you have installed mod_python, you must enable the modules in apache2, equivalent to the above Load Module directive:
     30(Still on Debian) after you have installed mod_python, you must enable the modules in apache2 (equivalent of the above Load Module directive):
    2531{{{
    2632a2enmod python
     
    3036yum install mod_python
    3137}}}
    32 You 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+.
     38You 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+.
    3339{{{
    3440#!xml
     
    5662}}}
    5763
    58 The 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.
    59 
    60 The options available are:
     64The 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.
     65
     66The options available are
    6167{{{
    6268    # For a single project
     
    7985}}}
    8086
    81 === Python Egg Cache
    82 
    83 Compressed 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:
     87=== Python Egg Cache ===
     88
     89Compressed 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:
    8490{{{
    8591PythonOption PYTHON_EGG_CACHE /var/trac/myprojects/egg-cache
     
    8894or you can uncompress the Genshi egg to resolve problems extracting from it.
    8995
    90 === Configuring Authentication
     96=== Configuring Authentication ===
    9197
    9298See corresponding section in the [wiki:TracModWSGI#ConfiguringAuthentication] page.
    9399
     100
    94101== Advanced Configuration
    95102
    96 === Setting the Python Egg Cache
     103=== Setting the Python Egg Cache ===
    97104
    98105If 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.
     
    107114}}}
    108115
    109 === Setting the !PythonPath
     116
     117=== Setting the !PythonPath ===
    110118
    111119If 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:
     
    121129Be careful about using the !PythonPath directive, and ''not'' `SetEnv PYTHONPATH`, as the latter won't work.
    122130
    123 === Setting up multiple projects
     131=== Setting up multiple projects ===
    124132
    125133The Trac mod_python handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`:
     
    156164}}}
    157165
    158 === Virtual Host Configuration
    159 
    160 Below is the sample configuration required to set up your trac as a virtual server, ie when you access it at the URLs like
    161 !http://trac.mycompany.com:
     166=== Virtual Host Configuration ===
     167
     168Below is the sample configuration required to set up your trac as a virtual server (i.e. when you access it at the URLs like
     169!http://trac.mycompany.com):
    162170
    163171{{{
     
    184192This does not seem to work in all cases. What you can do if it does not:
    185193 * Try using `<LocationMatch>` instead of `<Location>`
    186  * <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, ie /web/ and /web/login instead of / and /login.
     194 * <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).
    187195 * Depending on apache's `NameVirtualHost` configuration, you may need to use `<VirtualHost *:80>` instead of `<VirtualHost *>`.
    188196
     
    191199Note: !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".
    192200
    193 == Troubleshooting
     201== Troubleshooting ==
    194202
    195203In general, if you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option:
     
    204212For multiple projects, try restarting the server as well.
    205213
    206 === Login Not Working
    207 
     214=== Login Not Working ===
    208215If you've used `<Location />` directive, it will override any other directives, as well as `<Location /login>`.
    209216The workaround is to use negation expression as follows (for multi project setups):
     
    240247
    241248This problem will most certainly hit you on Unix when using Python 2.4.
    242 In Python 2.4, some version of [http://expat.sourceforge.net/ Expat] (an XML parser library written in C) is used and if Apache is using another version, this results in segmentation faults.
    243 As Trac 0.11 is using Genshi, which will indirectly use Expat, that problem can now hit you even if everything was working fine before with Trac 0.10. This problem has not been reported for Python 2.5+, so best to upgrade.
    244 
    245 === Form submission problems
     249In Python 2.4, some version of Expat (an XML parser library written in C) is used,
     250and if Apache is using another version, this results in segmentation faults.
     251As Trac 0.11 is using Genshi, which will indirectly use Expat, that problem
     252can now hit you even if everything was working fine before with Trac 0.10.
     253
     254See Graham Dumpleton's detailed [http://www.dscpl.com.au/wiki/ModPython/Articles/ExpatCausingApacheCrash explanation and workarounds] for the issue.
     255
     256=== Form submission problems ===
    246257
    247258If 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.
    248259
    249 === Problem with virtual host configuration
    250 
    251 If 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.
    252 
    253 Using <Location /> together with `SetHandler` resulted in having everything handled by mod_python, which leads to not being able to download any CSS or images/icons. Use <Location /trac> `SetHandler None` </Location> to circumvent the problem, though this may not be the most elegant solution.
    254 
    255 === Problem with zipped egg
     260=== Problem with virtual host configuration ===
     261
     262If 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).
     263
     264Using <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.
     265
     266=== Problem with zipped egg ===
    256267
    257268It'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:
     
    261272}}}
    262273
    263 === Using .htaccess
     274=== Using .htaccess ===
    264275
    265276Although 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.
    266277
    267 It 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.
    268 
    269 This also works out-of-box, with following trivial config:
     278It 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. :)
     279
     280A success story: For me it worked out-of-box, with following trivial config:
    270281{{{#!xml
    271282SetHandler mod_python
     
    281292}}}
    282293
    283 The `TracUriRoot` is obviously the path you need to enter to the browser to get to Trac, eg domain.tld/projects/trac.
    284 
    285 === Additional .htaccess help
    286 
    287 If 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:
     294The `TracUriRoot` is obviously the path you need to enter to the browser to get to the trac (e.g. domain.tld/projects/trac)
     295
     296=== Additional .htaccess help ===
     297
     298If 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:
    288299
    289300{{{
     
    294305
    295306=== Platform specific issues
    296 ==== Win32 Issues
    297 
     307==== Win32 Issues ====
    298308If 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.
    299309
    300 ==== OS X issues
    301 
    302 When 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, so please upgrade.
    303 
    304 ==== SELinux issues
     310
     311==== OS X issues ====
     312
     313When 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].
     314
     315==== SELinux issues ====
    305316
    306317If Trac reports something like: ''Cannot get shared lock on db.lock''
     
    311322}}}
    312323
    313 See also [http://subversion.apache.org/faq.html#reposperms How do I set repository permissions correctly?]
    314 
    315 ==== FreeBSD issues
    316 
    317 The FreeBSD ports have both the new and old versions of mod_python and SQLite, 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.
    318 
    319 If you compiled and installed apache2, threads are not automatically supported on FreeBSD. You could force thread support when running `./configure` for Apache, using `--enable-threads`, but this isn´t recommended.
    320 The best option [http://modpython.org/pipermail/mod_python/2006-September/021983.html seems to be] adding to /usr/local/apache2/bin/ennvars the line:
     324See also [http://subversion.tigris.org/faq.html#reposperms]
     325
     326==== FreeBSD issues ====
     327Pay 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.
     328
     329If 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.
     330The best option [http://modpython.org/pipermail/mod_python/2006-September/021983.html seems to be] adding to /usr/local/apache2/bin/ennvars the line
    321331
    322332{{{
     
    324334}}}
    325335
    326 ==== Fedora 7 Issues
    327 
    328 Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython but not for tracd.
    329 
    330 === Subversion issues
    331 
    332 If 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.
    333 
    334 If this is not the case, it's possible that you're using Subversion libraries that are binary incompatible with the Apache ones and 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`).
    335 
    336 You 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. Version 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:
     336
     337==== Fedora 7 Issues ====
     338Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython but not for tracd
     339
     340
     341=== Subversion issues ===
     342
     343If 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.)
     344
     345If 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`).
     346
     347You 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:
    337348{{{
    338349PythonInterpreter main_interpreter
    339350}}}
    340 
    341351This 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.
    342352
    343 === Page layout issues
    344 
    345 If 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:
     353=== Page layout issues ===
     354
     355If 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:
    346356{{{
    347357#!xml
     
    354364Note: For the above configuration to have any effect it must be put after the configuration of your project root location, i.e. {{{<Location /myproject />}}}.
    355365
    356 Also, 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, leave it `Off`.
    357 
    358 === HTTPS issues
     366Also, 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`.
     367
     368=== HTTPS issues ===
    359369
    360370If 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:
     
    369379}}}
    370380
    371 === Segmentation fault with php5-mhash or other php5 modules
    372 
    373 You 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 [http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=411487 Debian bug report].
    374 
    375 Some people also have troubles when using php5 compiled with its own 3rd party libraries instead of system libraries. Check [http://www.djangoproject.com/documentation/modpython/#if-you-get-a-segmentation-fault Django segmentation fault].
     381
     382=== Segmentation fault with php5-mhash or other php5 modules ===
     383You 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]
     384
     385Some 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]
    376386
    377387----
    378 See also: TracGuide, TracInstall, [wiki:TracModWSGI ModWSGI], [wiki:TracFastCgi FastCGI], [trac:TracNginxRecipe]
     388See also:  TracGuide, TracInstall, [wiki:TracModWSGI ModWSGI], [wiki:TracFastCgi FastCGI],  [trac:TracNginxRecipe TracNginxRecipe]