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1= Trac and mod_wsgi =
2
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
10Trac 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
13In its simplest form, the script could be:
14
15{{{#!python
16import os
17
18os.environ['TRAC_ENV'] = '/usr/local/trac/mysite'
19os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
20
21import trac.web.main
22application = trac.web.main.dispatch_request
23}}}
24
25The `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.
26
27=== A more elaborate script
28
29If 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
31To solve this problem, use the following `.wsgi` file instead:
32{{{#!python
33import os
34
35os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
36
37import trac.web.main
38def application(environ, start_response):
39  environ['trac.env_path'] = '/usr/local/trac/mysite' 
40  return trac.web.main.dispatch_request(environ, start_response)
41}}}
42
43For 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
45If 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
48import site
49site.addsitedir('/usr/local/trac/lib/python2.4/site-packages')
50}}}
51
52Change it according to the path you installed the Trac libs at.
53
54=== Recommended `trac.wsgi` script
55
56A 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
61After you've done preparing your .wsgi script, add the following to your Apache configuration file (`httpd.conf` for example).
62
63{{{
64WSGIScriptAlias /trac /usr/local/trac/mysite/apache/mysite.wsgi
65
66<Directory /usr/local/trac/mysite/apache>
67    WSGIApplicationGroup %{GLOBAL}
68    Order deny,allow
69    Allow from all
70</Directory>
71}}}
72
73Here, the script is in a subdirectory of the Trac environment.
74
75If 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{{{
78WSGIScriptAlias /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
87In 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
89To 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
92def application(environ, start_response):
93        start_response('200 OK',[('Content-type','text/html')])
94        return ['<html><body>Hello World!</body></html>']
95}}}
96
97For 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
102We describe in the the following sections different methods for setting up authentication.
103
104See 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
108The 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
111New password: <type password>
112Re-type new password: <type password again>
113Adding password for user admin
114}}}
115
116After the first user, you dont need the "-c" option anymore:
117{{{
118$ htpasswd /somewhere/trac.htpasswd john
119New password: <type password>
120Re-type new password: <type password again>
121Adding password for user john
122}}}
123
124  ''See the man page for `htpasswd` for full documentation.''
125
126After you've created the users, you can set their permissions using TracPermissions.
127
128Now, 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
138If 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}}}
147Note that neither a file nor a directory named 'login' needs to exist.[[BR]]
148See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_basic.html mod_auth_basic] documentation.
149
150=== Using Digest Authentication ===
151
152For better security, it is recommended that you either enable SSL or at least use the digest authentication scheme instead of Basic. 
153
154You'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
159The "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
172For multiple environments, you can use the same `LocationMatch` as described with the previous method.
173
174Don'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
180See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html mod_auth_digest] documentation.
181
182=== Using LDAP Authentication
183
184Configuration 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
1861. You need to load the following modules in Apache httpd.conf
187{{{
188LoadModule ldap_module modules/mod_ldap.so
189LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
190}}}
191
1922. 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
2103. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory:
211
212
213Use the following as your LDAP URL:
214{{{
215    AuthLDAPURL "ldap://directory.example.com:3268/DC=example,DC=com?sAMAccountName?sub?(objectClass=user)"
216}}}
217
218You will also need to provide an account for Apache to use when checking
219credentials. As this password will be listed in plaintext in the
220config, 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
226The 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
245Note 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
247Note 2: You can also require the user be a member of a certain LDAP group, instead of
248just having a valid login:
249{{{
250    Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
251}}}
252
253See 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
261If you are using Apache on Windows, you can use mod_auth_sspi to provide
262single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the
263following 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
278Using the above, usernames in Trac will be of the form `DOMAIN\username`, so
279you may have to re-add permissions and such. If you do not want the domain to
280be part of the username, set `SSPIOmitDomain On` instead.
281
282Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
283
284See also [trac:TracOnWindows/Advanced].
285
286=== Using Apache authentication with the Account Manager plugin's Login form ===
287
288To 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
292Here 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
296acct_mgr.http.HttpAuthStore = enabled
297
298[account-manager]
299; configure the plugin to use a page that is secured with http authentication
300authentication_url = /authFile
301password_store = HttpAuthStore
302}}}
303This will generally be matched with an Apache config like:
304{{{
305<Location /authFile>
306   HTTP authentication configuration
307   Require valid-user
308</Location>
309}}}
310Note 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
314Per 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
317If 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
319Create the htpasswd file:
320{{{
321cd /home/trac-for-my-proj/the-env
322htpasswd -c htpasswd firstuser
323### and add more users to it as needed:
324htpasswd htpasswd seconduser
325}}}
326(keep the file above your document root for security reasons)
327
328Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following contents:
329
330{{{
331<Directory /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi>
332  WSGIApplicationGroup %{GLOBAL}
333  Order deny,allow
334  Allow from all
335</Directory>
336
337<VirtualHost *:80>
338  ServerName trac.my-proj.my-site.org
339  DocumentRoot /home/trac-for-my-proj/the-env/htdocs/
340  WSGIScriptAlias / /home/trac-for-my-proj/the-deploy/cgi-bin/trac.wsgi
341  <Location '/'>
342    AuthType Basic
343    AuthName "Trac"
344    AuthUserFile /home/trac-for-my-proj/the-env/htpasswd
345    Require valid-user
346  </Location>
347</VirtualHost>
348
349}}}
350
351Note: 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
358Please 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
362If 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' ===
365If 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'.
366
367This WSGI script 'fixes' things, hope it helps:
368{{{#!python
369import os
370import trac.web.main
371
372os.environ['TRAC_ENV'] = '/usr/local/trac/mysite'
373os.environ['PYTHON_EGG_CACHE'] = '/usr/local/trac/mysite/eggs'
374
375def application(environ, start_response):
376    if "\\" in environ['REMOTE_USER']:
377        environ['REMOTE_USER'] = environ['REMOTE_USER'].split("\\", 1)[1]
378    return trac.web.main.dispatch_request(environ, start_response)
379}}}
380
381
382=== Trac with PostgreSQL ===
383
384When 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
386A 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
388But it's not necessary to edit the source of Trac, the following lines in `trac.wsgi` will also work:
389
390{{{
391import trac.db.postgres_backend
392trac.db.postgres_backend.PostgreSQLConnection.poolable = False
393}}}
394
395or
396
397{{{
398import trac.db.mysql_backend
399trac.db.mysql_backend.MySQLConnection.poolable = False
400}}}
401
402Now 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
408For 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
411----
412See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]
Note: See TracBrowser for help on using the repository browser.