Changeset 38412 for wiki/pages/TracModPython
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- 08/29/16 00:35:09 (6 years ago)
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wiki/pages/TracModPython
r37567 r38412 1 [[TracGuideToc]]2 3 = Trac and mod_python4 5 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.6 Trac 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.7 8 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.9 10 [[PageOutline(2-3,Overview,inline)]]11 12 == Simple configuration: single project == #Simpleconfiguration13 14 If you just installed mod_python, you may have to add a line to load the module in the Apache configuration:15 {{{#!apache16 LoadModule python_module modules/mod_python.so17 }}}18 19 '''Note''': The exact path to the module depends on how the HTTPD installation is laid out.20 21 On Debian using apt-get:22 {{{#!sh23 apt-get install libapache2-mod-python libapache2-mod-python-doc24 }}}25 26 Still on Debian, after you have installed mod_python, you must enable the modules in apache2, equivalent to the above Load Module directive:27 {{{#!sh28 a2enmod python29 }}}30 31 On Fedora use, using yum:32 {{{#!sh33 yum install mod_python34 }}}35 36 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+.37 {{{#!apache38 <Location /mpinfo>39 SetHandler mod_python40 PythonInterpreter main_interpreter41 PythonHandler mod_python.testhandler42 Order allow,deny43 Allow from all44 </Location>45 }}}46 47 A simple setup of Trac on mod_python looks like this:48 {{{#!apache49 <Location /projects/myproject>50 SetHandler mod_python51 PythonInterpreter main_interpreter52 PythonHandler trac.web.modpython_frontend53 PythonOption TracEnv /var/trac/myproject54 PythonOption TracUriRoot /projects/myproject55 Order allow,deny56 Allow from all57 </Location>58 }}}59 60 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.61 62 The options available are:63 {{{#!apache64 # For a single project65 PythonOption TracEnv /var/trac/myproject66 67 # For multiple projects68 PythonOption TracEnvParentDir /var/trac/myprojects69 70 # For the index of multiple projects71 PythonOption TracEnvIndexTemplate /srv/www/htdocs/trac/project_list_template.html72 73 # A space delimitted list, with a "," between key and value pairs.74 PythonOption TracTemplateVars key1,val1 key2,val275 76 # Useful to get the date in the wanted order77 PythonOption TracLocale en_GB.UTF878 79 # See description above80 PythonOption TracUriRoot /projects/myproject81 }}}82 83 === Python Egg Cache84 85 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 writeable, an alternate egg cache directory can be specified like this:86 {{{#!apache87 PythonOption PYTHON_EGG_CACHE /var/trac/myprojects/egg-cache88 }}}89 90 Or you can uncompress the Genshi egg to resolve problems extracting from it.91 92 === Configuring Authentication93 94 See corresponding section in the [wiki:TracModWSGI#ConfiguringAuthentication] page.95 96 == Advanced Configuration97 98 === Setting the Python Egg Cache99 100 If 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.101 102 {{{#!apache103 <Location /projects/myproject>104 ...105 PythonOption PYTHON_EGG_CACHE /tmp106 ...107 </Location>108 }}}109 110 === Setting the !PythonPath111 112 If the Trac installation isn't installed in your Python path, you will have to tell Apache where to find the Trac mod_python handler using the `PythonPath` directive:113 {{{#!apache114 <Location /projects/myproject>115 ...116 PythonPath "sys.path + ['/path/to/trac']"117 ...118 </Location>119 }}}120 121 Be careful about using the !PythonPath directive, and ''not'' `SetEnv PYTHONPATH`, as the latter won't work.122 123 === Setting up multiple projects124 125 The Trac mod_python handler supports a configuration option similar to Subversion's `SvnParentPath`, called `TracEnvParentDir`:126 {{{#!apache127 <Location /projects>128 SetHandler mod_python129 PythonInterpreter main_interpreter130 PythonHandler trac.web.modpython_frontend131 PythonOption TracEnvParentDir /var/trac132 PythonOption TracUriRoot /projects133 </Location>134 }}}135 136 When 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.137 138 If you don't want to have the subdirectory listing as your projects home page you can use a139 {{{#!apache140 <LocationMatch "/.+/">141 }}}142 143 This 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.144 145 You can also use the same authentication realm for all of the projects using a `<LocationMatch>` directive:146 {{{#!apache147 <LocationMatch "/projects/[^/]+/login">148 AuthType Basic149 AuthName "Trac"150 AuthUserFile /var/trac/.htpasswd151 Require valid-user152 </LocationMatch>153 }}}154 155 === Virtual Host Configuration156 157 Below is the sample configuration required to set up your Trac as a virtual server, ie when you access it at the URLs like158 `http://trac.mycompany.com`:159 160 {{{#!apache161 <VirtualHost *>162 DocumentRoot /var/www/myproject163 ServerName trac.mycompany.com164 <Location />165 SetHandler mod_python166 PythonInterpreter main_interpreter167 PythonHandler trac.web.modpython_frontend168 PythonOption TracEnv /var/trac/myproject169 PythonOption TracUriRoot /170 </Location>171 <Location /login>172 AuthType Basic173 AuthName "MyCompany Trac Server"174 AuthUserFile /var/trac/myproject/.htpasswd175 Require valid-user176 </Location>177 </VirtualHost>178 }}}179 180 This does not seem to work in all cases. What you can do if it does not:181 * Try using `<LocationMatch>` instead of `<Location>`.182 * `<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, ie you get the infamous Authentication information missing error. If this is the case, try using a sub-directory for Trac instead of the root, ie /web/ and /web/login instead of / and /login.183 * Depending on apache's `NameVirtualHost` configuration, you may need to use `<VirtualHost *:80>` instead of `<VirtualHost *>`.184 185 For a virtual host that supports multiple projects replace `TracEnv /var/trac/myproject` with `TracEnvParentDir /var/trac`.186 187 '''Note''': !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".188 189 == Troubleshooting190 191 If you get server error pages, you can either check the Apache error log, or enable the `PythonDebug` option:192 {{{#!apache193 <Location /projects/myproject>194 ...195 PythonDebug on196 </Location>197 }}}198 199 For multiple projects, try restarting the server as well.200 201 === Login Not Working202 203 If you've used `<Location />` directive, it will override any other directives, as well as `<Location /login>`.204 The workaround is to use negation expression as follows (for multi project setups):205 {{{#!apache206 #this one for other pages207 <Location ~ "/*(?!login)">208 SetHandler mod_python209 PythonHandler trac.web.modpython_frontend210 PythonOption TracEnvParentDir /projects211 PythonOption TracUriRoot /212 </Location>213 214 #this one for login page215 <Location ~ "/[^/]+/login">216 SetHandler mod_python217 PythonHandler trac.web.modpython_frontend218 PythonOption TracEnvParentDir /projects219 PythonOption TracUriRoot /220 221 #remove these if you don't want to force SSL222 RewriteEngine On223 RewriteCond %{HTTPS} off224 RewriteRule (.*) https://%{HTTP_HOST}%{REQUEST_URI}225 226 AuthType Basic227 AuthName "Trac"228 AuthUserFile /projects/.htpasswd229 Require valid-user230 </Location>231 }}}232 233 === Expat-related segmentation faults === #expat234 235 This problem will most certainly hit you on Unix when using Python 2.4.236 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.237 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.238 239 === Form submission problems240 241 If 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.242 243 === Problem with virtual host configuration244 245 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.246 247 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.248 249 === Problem with zipped egg250 251 It'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 this, try installing Trac using the `--always-unzip` option:252 253 {{{#!sh254 easy_install --always-unzip Trac-0.12b1.zip255 }}}256 257 === Using .htaccess258 259 Although 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.260 261 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.262 263 This also works out-of-box, with following trivial config:264 {{{#!apache265 SetHandler mod_python266 PythonInterpreter main_interpreter267 PythonHandler trac.web.modpython_frontend268 PythonOption TracEnv /system/path/to/this/directory269 PythonOption TracUriRoot /path/on/apache270 271 AuthType Basic272 AuthName "ProjectName"273 AuthUserFile /path/to/.htpasswd274 Require valid-user275 }}}276 277 The `TracUriRoot` is obviously the path you need to enter to the browser to get to Trac, eg `domain.tld/projects/trac`.278 279 === Additional .htaccess help280 281 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:282 283 {{{#!apache284 <IfModule mod_rewrite.c>285 RewriteEngine Off286 </IfModule>287 }}}288 289 === Platform specific issues290 ==== Win32 Issues291 292 If 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.293 294 ==== OS X issues295 296 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 mod_python to fix this.297 298 ==== SELinux issues299 300 If Trac reports something like: `Cannot get shared lock on db.lock`, then the security context on the repository may need to be set:301 302 {{{#!sh303 chcon -R -h -t httpd_sys_content_t PATH_TO_REPOSITORY304 }}}305 306 See also [http://subversion.apache.org/faq.html#reposperms How do I set repository permissions correctly?]307 308 ==== FreeBSD issues309 310 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:311 * pysqlite requires threaded support in Python312 * mod_python requires a threadless install.313 314 Apache2 does not automatically support threads on FreeBSD. You could force thread support when running `./configure` for Apache, using `--enable-threads`, but this isn´t recommended.315 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:316 317 {{{#!sh318 export LD_PRELOAD=/usr/lib/libc_r.so319 }}}320 321 ==== Fedora 7 Issues322 323 Make sure you install the 'python-sqlite2' package as it seems to be required for TracModPython, but not for tracd.324 325 === Subversion issues326 327 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. A better way is to add a link to the bindings in the Python `site-packages` directory, or create a `.pth` file in that directory.328 329 If this is not the case, it's possible that you are 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`).330 331 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:332 {{{#!apache333 PythonInterpreter main_interpreter334 }}}335 336 This is also the recommended workaround for other 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.337 338 === Page layout issues339 340 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:341 {{{#!apache342 Alias /myproject/css "/usr/share/trac/htdocs/css"343 <Location /myproject/css>344 SetHandler None345 </Location>346 }}}347 348 '''Note''': For the above configuration to have any effect it must be put after the configuration of your project root location, ie {{{<Location /myproject />}}}.349 350 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`.351 352 === HTTPS issues353 354 If 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:355 {{{#!apache356 <VirtualHost *>357 DocumentRoot /var/www/myproject358 ServerName trac.mycompany.com359 SetEnv HTTPS 1360 ....361 </VirtualHost>362 }}}363 364 === Segmentation fault with php5-mhash or other php5 modules365 366 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].367 368 Some people also have troubles when using PHP5 compiled with its own third party libraries instead of system libraries. Check [http://www.djangoproject.com/documentation/modpython/#if-you-get-a-segmentation-fault Django segmentation fault].369 370 ----371 See also: TracGuide, TracInstall, [wiki:TracModWSGI ModWSGI], [wiki:TracFastCgi FastCGI], [trac:TracNginxRecipe]
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