Changes between Version 2 and Version 3 of TracModWSGI
- Timestamp:
- 09/26/12 15:33:42 (12 years ago)
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TracModWSGI
v2 v3 1 1 = Trac and mod_wsgi = 2 2 3 '''Important note:''' ''Please use either version 1.6, 2.4 or later of `mod_wsgi`. Versions prior to 2.4 in the 2.X branch have problems with some Apache configurations that use WSGI file wrapper extension. This extension is used in Trac to serve up attachments and static media files such as style sheets. If you are affected by this problem attachments will appear to be empty and formatting of HTML pages will appear not to work due to style sheet files not loading properly. See mod_wsgi tickets [http://code.google.com/p/modwsgi/issues/detail?id=100 #100] and [http://code.google.com/p/modwsgi/issues/detail?id=132 #132].'' 4 5 [http://code.google.com/p/modwsgi/ mod_wsgi] is an Apache module for running WSGI-compatible Python applications directly on top of Apache. The mod_wsgi adapter is written completely in C and provides significantly better performance than using existing WSGI adapters for mod_python or CGI. 6 7 Trac can be run on top of mod_wsgi with the help of the following application script, which is just a Python file, though usually saved with a .wsgi extension). This file can be created using '''trac-admin <env> deploy <dir>''' command which automatically substitutes required paths. 8 9 {{{ 10 #!python 3 4 [http://code.google.com/p/modwsgi/ mod_wsgi] is an Apache module for running WSGI-compatible Python applications directly on top of the Apache webserver. The mod_wsgi adapter is written completely in C and provides very good performances. 5 6 [[PageOutline(2-3,Overview,inline)]] 7 8 == The `trac.wsgi` script 9 10 Trac can be run on top of mod_wsgi with the help of the following application script, which is just a Python file, though usually saved with a `.wsgi` extension). 11 12 === A very basic script 13 In its simplest form, the script could be: 14 15 {{{#!python 11 16 import os 12 17 … … 20 25 The `TRAC_ENV` variable should naturally be the directory for your Trac environment (if you have several Trac environments in a directory, you can also use `TRAC_ENV_PARENT_DIR` instead), while the `PYTHON_EGG_CACHE` should be a directory where Python can temporarily extract Python eggs. 21 26 22 '''Important note:''' If you're using multiple `.wsgi` files (for example one per Trac environment) you must ''not'' use `os.environ['TRAC_ENV']` to set the path to the Trac environment. Using this method may lead to Trac delivering the content of another Trac environment. (The variable may be filled with the path of a previously viewed Trac environment.) To solve this problem, use the following `.wsgi` file instead: 23 24 {{{ 25 #!python 27 === A more elaborate script 28 29 If you're using multiple `.wsgi` files (for example one per Trac environment) you must ''not'' use `os.environ['TRAC_ENV']` to set the path to the Trac environment. Using this method may lead to Trac delivering the content of another Trac environment, as the variable may be filled with the path of a previously viewed Trac environment. 30 31 To solve this problem, use the following `.wsgi` file instead: 32 {{{#!python 26 33 import os 27 34 … … 34 41 }}} 35 42 36 For clarity, you should give this file a `.wsgi` extension. You should probably put the file in it's own directory, since you will open up its directory to Apache. You can create a .wsgi files which handles all this for you by running the TracAdmin command `deploy`. 37 38 If you have installed trac and eggs in a path different from the standard one you should add that path by adding the following code on top of the wsgi script: 39 40 {{{ 41 #!python 43 For clarity, you should give this file a `.wsgi` extension. You should probably put the file in its own directory, since you will expose it to Apache. 44 45 If you have installed Trac and eggs in a path different from the standard one you should add that path by adding the following code at the top of the wsgi script: 46 47 {{{#!python 42 48 import site 43 49 site.addsitedir('/usr/local/trac/lib/python2.4/site-packages') 44 50 }}} 45 51 46 Change it according to the path you installed the trac libs at. 47 48 After you've done preparing your wsgi-script, add the following to your httpd.conf. 52 Change it according to the path you installed the Trac libs at. 53 54 === Recommended `trac.wsgi` script 55 56 A somewhat robust and generic version of this file can be created using the `trac-admin <env> deploy <dir>` command which automatically substitutes the required paths (see TracInstall#cgi-bin). 57 58 59 == Mapping requests to the script 60 61 After you've done preparing your .wsgi script, add the following to your Apache configuration file (`httpd.conf` for example). 49 62 50 63 {{{ … … 58 71 }}} 59 72 60 Here, the script is in a subdirectory of the Trac environment. In order to let Apache run the script, access to the directory in which the script resides is opened up to all of Apache. Additionally, the {{{WSGIApplicationGroup}}} directive ensures that Trac is always run in the first Python interpreter created by mod_wsgi; this is necessary because the Subversion Python bindings, which are used by Trac, don't always work in other subinterpreters and may cause requests to hang or cause Apache to crash as a result. After adding this configuration, restart Apache, and then it should work. 61 62 To test the setup of Apache, mod_wsgi and Python itself (ie. without involving Trac and dependencies), this simple wsgi application can be used to make sure that requests gets served (use as only content in your .wsgi script): 63 64 {{{ 73 Here, the script is in a subdirectory of the Trac environment. 74 75 If you followed the directions [http://trac.edgewall.org/wiki/TracInstall#cgi-bin Generating the Trac cgi-bin directory], your Apache configuration file should look like following: 76 77 {{{ 78 WSGIScriptAlias /trac /usr/share/trac/cgi-bin/trac.wsgi 79 80 <Directory /usr/share/trac/cgi-bin> 81 WSGIApplicationGroup %{GLOBAL} 82 Order deny,allow 83 Allow from all 84 </Directory> 85 }}} 86 87 In order to let Apache run the script, access to the directory in which the script resides is opened up to all of Apache. Additionally, the `WSGIApplicationGroup` directive ensures that Trac is always run in the first Python interpreter created by mod_wsgi; this is necessary because the Subversion Python bindings, which are used by Trac, don't always work in other sub-interpreters and may cause requests to hang or cause Apache to crash as a result. After adding this configuration, restart Apache, and then it should work. 88 89 To test the setup of Apache, mod_wsgi and Python itself (ie. without involving Trac and dependencies), this simple wsgi application can be used to make sure that requests gets served (use as only content in your `.wsgi` script): 90 91 {{{#!python 65 92 def application(environ, start_response): 66 93 start_response('200 OK',[('Content-type','text/html')]) … … 68 95 }}} 69 96 70 See also the mod_wsgi [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac installation instructions] for Trac. 71 72 For troubleshooting tips, see the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [http://code.google.com/p/modwsgi/wiki/ApplicationIssues application issues] when using mod_wsgi. 73 74 ''Note: using mod_wsgi 2.5 and Python 2.6.1 gave an Internal Server Error on my system (Apache 2.2.11 and Trac 0.11.2.1). Upgrading to Python 2.6.2 (as suggested [http://www.mail-archive.com/modwsgi@googlegroups.com/msg01917.html here]) solved this for me[[BR]]-- Graham Shanks'' 75 76 == Apache Basic Authentication for Trac thru mod_wsgi == 77 78 Per the mod_wsgi documentation linked to above, here is an example Apache configuration that a) serves the trac from a virtualhost subdomain and b) uses Apache basic authentication for Trac authentication. 79 80 81 If you want your trac to be served from e.g. !http://trac.my-proj.my-site.org, then from the folder e.g. {{{/home/trac-for-my-proj}}}, if you used the command {{{trac-admin the-env initenv}}} to create a folder {{{the-env}}}, and you used {{{trac-admin the-env deploy the-deploy}}} to create a folder {{{the-deploy}}}, then: 82 83 create the htpasswd file: 97 For more information about using the mod_wsgi specific directives, see the [http://code.google.com/p/modwsgi/wiki/ mod_wsgi's wiki] and more specifically the [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac IntegrationWithTrac] page. 98 99 100 == Configuring Authentication 101 102 We describe in the the following sections different methods for setting up authentication. 103 104 See also [http://httpd.apache.org/docs/2.2/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide. 105 106 === Using Basic Authentication === 107 108 The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program to create the password file: 109 {{{ 110 $ htpasswd -c /somewhere/trac.htpasswd admin 111 New password: <type password> 112 Re-type new password: <type password again> 113 Adding password for user admin 114 }}} 115 116 After the first user, you dont need the "-c" option anymore: 117 {{{ 118 $ htpasswd /somewhere/trac.htpasswd john 119 New password: <type password> 120 Re-type new password: <type password again> 121 Adding password for user john 122 }}} 123 124 ''See the man page for `htpasswd` for full documentation.'' 125 126 After you've created the users, you can set their permissions using TracPermissions. 127 128 Now, you'll need to enable authentication against the password file in the Apache configuration: 129 {{{ 130 <Location "/trac/login"> 131 AuthType Basic 132 AuthName "Trac" 133 AuthUserFile /somewhere/trac.htpasswd 134 Require valid-user 135 </Location> 136 }}} 137 138 If you're hosting multiple projects you can use the same password file for all of them: 139 {{{ 140 <LocationMatch "/trac/[^/]+/login"> 141 AuthType Basic 142 AuthName "Trac" 143 AuthUserFile /somewhere/trac.htpasswd 144 Require valid-user 145 </LocationMatch> 146 }}} 147 Note that neither a file nor a directory named 'login' needs to exist.[[BR]] 148 See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_basic.html mod_auth_basic] documentation. 149 150 === Using Digest Authentication === 151 152 For better security, it is recommended that you either enable SSL or at least use the “digest” authentication scheme instead of “Basic”. 153 154 You'll have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows: 155 {{{ 156 # htdigest -c /somewhere/trac.htpasswd trac admin 157 }}} 158 159 The "trac" parameter above is the "realm", and will have to be reused in the Apache configuration in the !AuthName directive: 160 161 {{{ 162 <Location "/trac/login"> 163 164 AuthType Digest 165 AuthName "trac" 166 AuthDigestDomain /trac 167 AuthUserFile /somewhere/trac.htpasswd 168 Require valid-user 169 </Location> 170 }}} 171 172 For multiple environments, you can use the same `LocationMatch` as described with the previous method. 173 174 Don't forget to activate the mod_auth_digest. For example, on a Debian 4.0r1 (etch) system: 175 {{{ 176 LoadModule auth_digest_module /usr/lib/apache2/modules/mod_auth_digest.so 177 }}} 178 179 180 See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html mod_auth_digest] documentation. 181 182 === Using LDAP Authentication 183 184 Configuration for [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap] authentication in Apache is a bit tricky (httpd 2.2.x and OpenLDAP: slapd 2.3.19) 185 186 1. You need to load the following modules in Apache httpd.conf 187 {{{ 188 LoadModule ldap_module modules/mod_ldap.so 189 LoadModule authnz_ldap_module modules/mod_authnz_ldap.so 190 }}} 191 192 2. Your httpd.conf also needs to look something like: 193 194 {{{ 195 <Location /trac/> 196 # (if you're using it, mod_python specific settings go here) 197 Order deny,allow 198 Deny from all 199 Allow from 192.168.11.0/24 200 AuthType Basic 201 AuthName "Trac" 202 AuthBasicProvider "ldap" 203 AuthLDAPURL "ldap://127.0.0.1/dc=example,dc=co,dc=ke?uid?sub?(objectClass=inetOrgPerson)" 204 authzldapauthoritative Off 205 Require valid-user 206 </Location> 207 }}} 208 209 210 3. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory: 211 212 213 Use the following as your LDAP URL: 214 {{{ 215 AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)" 216 }}} 217 218 You will also need to provide an account for Apache to use when checking 219 credentials. As this password will be listed in plaintext in the 220 config, you should be sure to use an account specifically for this task: 221 {{{ 222 AuthLDAPBindDN ldap-auth-user@example.com 223 AuthLDAPBindPassword "password" 224 }}} 225 226 The whole section looks like: 227 {{{ 228 <Location /trac/> 229 # (if you're using it, mod_python specific settings go here) 230 Order deny,allow 231 Deny from all 232 Allow from 192.168.11.0/24 233 AuthType Basic 234 AuthName "Trac" 235 AuthBasicProvider "ldap" 236 AuthLDAPURL "ldap://adserver.company.com:3268/DC=company,DC=com?sAMAccountName?sub?(objectClass=user)" 237 AuthLDAPBindDN ldap-auth-user@company.com 238 AuthLDAPBindPassword "the_password" 239 authzldapauthoritative Off 240 # require valid-user 241 require ldap-group CN=Trac Users,CN=Users,DC=company,DC=com 242 </Location> 243 }}} 244 245 Note 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. 246 247 Note 2: You can also require the user be a member of a certain LDAP group, instead of 248 just having a valid login: 249 {{{ 250 Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com 251 }}} 252 253 See also: 254 - [http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap 255 256 - [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap], documentation for mod_ldap, which provides connection pooling and a shared cache. 257 - [http://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP. 258 259 === Using SSPI Authentication 260 261 If you are using Apache on Windows, you can use mod_auth_sspi to provide 262 single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the 263 following to your !VirtualHost: 264 {{{ 265 <Location /trac/login> 266 AuthType SSPI 267 AuthName "Trac Login" 268 SSPIAuth On 269 SSPIAuthoritative On 270 SSPIDomain MyLocalDomain 271 SSPIOfferBasic On 272 SSPIOmitDomain Off 273 SSPIBasicPreferred On 274 Require valid-user 275 </Location> 276 }}} 277 278 Using the above, usernames in Trac will be of the form `DOMAIN\username`, so 279 you may have to re-add permissions and such. If you do not want the domain to 280 be part of the username, set `SSPIOmitDomain On` instead. 281 282 Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338]. 283 284 See also [trac:TracOnWindows/Advanced]. 285 286 === Using Apache authentication with the Account Manager plugin's Login form === 287 288 To begin with, see the basic instructions for using the Account Manager plugin's [http://trac-hacks.org/wiki/AccountManagerPlugin/Modules#LoginModule Login module] and its [http://trac-hacks.org/wiki/AccountManagerPlugin/AuthStores#HttpAuthStore HttpAuthStore authentication module]. 289 290 '''Note:''' If is difficult to get !HttpAuthStore to work with WSGI when using any Account Manager version prior to acct_mgr-0.4. Upgrading is recommended. 291 292 Here is an example (from the !HttpAuthStore link) using acct_mgr-0.4 for hosting a single project: 293 {{{ 294 [components] 295 ; be sure to enable the component 296 acct_mgr.http.HttpAuthStore = enabled 297 298 [account-manager] 299 ; configure the plugin to use a page that is secured with http authentication 300 authentication_url = /authFile 301 password_store = HttpAuthStore 302 }}} 303 This will generally be matched with an Apache config like: 304 {{{ 305 <Location /authFile> 306 …HTTP authentication configuration… 307 Require valid-user 308 </Location> 309 }}} 310 Note that '''authFile''' need not exist. See the !HttpAuthStore link above for examples where multiple Trac projects are hosted on a server. 311 312 === Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host 313 314 Per the mod_wsgi documentation linked to above, here is an example Apache configuration that a) serves the Trac instance from a virtualhost subdomain and b) uses Apache basic authentication for Trac authentication. 315 316 317 If you want your Trac to be served from e.g. !http://trac.my-proj.my-site.org, then from the folder e.g. `/home/trac-for-my-proj`, if you used the command `trac-admin the-env initenv` to create a folder `the-env`, and you used `trac-admin the-env deploy the-deploy` to create a folder `the-deploy`, then first: 318 319 Create the htpasswd file: 84 320 {{{ 85 321 cd /home/trac-for-my-proj/the-env … … 88 324 htpasswd htpasswd seconduser 89 325 }}} 90 ( for security keep the file above your document root)91 92 create this file e.g. (ubuntu) {{{/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf}}} with thesecontents:326 (keep the file above your document root for security reasons) 327 328 Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following contents: 93 329 94 330 {{{ … … 113 349 }}} 114 350 115 116 (for subdomains to work you would probably also need to alter /etc/hosts and add A-Records to your host's DNS.) 117 118 == Trac with PostgreSQL == 119 120 When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as a database back-end the server can get a lot of open database connections. (and thus PostgreSQL processes) 121 122 A workable solution is to disabled connection pooling in Trac. This is done by setting poolable = False in trac.db.postgres_backend on the PostgreSQLConnection class. 123 124 But it's not necessary to edit the source of trac, the following lines in trac.wsgi will also work: 125 126 {{{ 127 import trac.db.postgres_backend 128 trac.db.postgres_backend.PostgreSQLConnection.poolable = False 129 }}} 130 131 Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal. 132 133 == Getting Trac to work nicely with SSPI and 'Require Group' == 351 Note: for subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS. 352 353 354 == Troubleshooting 355 356 === Use a recent version 357 358 Please use either version 1.6, 2.4 or later of `mod_wsgi`. Versions prior to 2.4 in the 2.X branch have problems with some Apache configurations that use WSGI file wrapper extension. This extension is used in Trac to serve up attachments and static media files such as style sheets. If you are affected by this problem attachments will appear to be empty and formatting of HTML pages will appear not to work due to style sheet files not loading properly. Another frequent symptom is that binary attachment downloads are truncated. See mod_wsgi tickets [http://code.google.com/p/modwsgi/issues/detail?id=100 #100] and [http://code.google.com/p/modwsgi/issues/detail?id=132 #132]. 359 360 ''Note: using mod_wsgi 2.5 and Python 2.6.1 gave an Internal Server Error on my system (Apache 2.2.11 and Trac 0.11.2.1). Upgrading to Python 2.6.2 (as suggested [http://www.mail-archive.com/modwsgi@googlegroups.com/msg01917.html here]) solved this for me[[BR]]-- Graham Shanks'' 361 362 If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you'll even need version 0.3.4 or greater (see [trac:#10675] for details). 363 364 === Getting Trac to work nicely with SSPI and 'Require Group' === 134 365 If like me you've set Trac up on Apache, Win32 and configured SSPI, but added a 'Require group' option to your apache configuration, then the SSPIOmitDomain option is probably not working. If its not working your usernames in trac are probably looking like 'DOMAIN\user' rather than 'user'. 135 366 136 367 This WSGI script 'fixes' things, hope it helps: 137 {{{ 368 {{{#!python 138 369 import os 139 370 import trac.web.main … … 147 378 return trac.web.main.dispatch_request(environ, start_response) 148 379 }}} 380 381 382 === Trac with PostgreSQL === 383 384 When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as a database back-end, the server ''may'' create a lot of open database connections and thus PostgreSQL processes. 385 386 A somewhat brutal workaround is to disabled connection pooling in Trac. This is done by setting `poolable = False` in `trac.db.postgres_backend` on the `PostgreSQLConnection` class. 387 388 But it's not necessary to edit the source of Trac, the following lines in `trac.wsgi` will also work: 389 390 {{{ 391 import trac.db.postgres_backend 392 trac.db.postgres_backend.PostgreSQLConnection.poolable = False 393 }}} 394 395 or 396 397 {{{ 398 import trac.db.mysql_backend 399 trac.db.mysql_backend.MySQLConnection.poolable = False 400 }}} 401 402 Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal. 403 404 //This is not a recommended approach though. See also the notes at the bottom of the [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac mod_wsgi's IntegrationWithTrac] wiki page.// 405 406 === Other resources 407 408 For more troubleshooting tips, see also the [TracModPython#Troubleshooting mod_python troubleshooting] section, as most Apache-related issues are quite similar, plus discussion of potential [http://code.google.com/p/modwsgi/wiki/ApplicationIssues application issues] when using mod_wsgi. The wsgi page also has a [http://code.google.com/p/modwsgi/wiki/IntegrationWithTrac Integration With Trac] document. 409 410 149 411 ---- 150 412 See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]