Changes between Version 3 and Version 4 of Trac ModWSGI


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Timestamp:
Feb 3, 2015, 5:53:07 PM (10 years ago)
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trac
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  • Trac ModWSGI

    v3 v4  
    11= Trac and mod_wsgi =
    22
    3 
    43[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 performance.
    54
    … …  
    87== The `trac.wsgi` script
    98
    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).
     9Trac 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.
    1110
    1211=== A very basic script
    … …  
    2322}}}
    2423
    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.
     24The `TRAC_ENV` variable should naturally be the directory for your Trac environment, and the `PYTHON_EGG_CACHE` should be a directory where Python can temporarily extract Python eggs. If you have several Trac environments in a directory, you can also use `TRAC_ENV_PARENT_DIR` instead of `TRAC_ENV`.
    2625
    2726On Windows:
    … …  
    3029os.environ['PYTHON_EGG_CACHE'] = r'C:\Users\Administrator\AppData\Roaming\Python-Eggs'
    3130}}}
    32  - If run under a Window service, you should create a directory for Python Egg cache.
     31 - If run under a Window service, you should create a directory for Python Egg cache:
    3332{{{#!python
    3433os.environ['PYTHON_EGG_CACHE'] = r'C:\Trac-Python-Eggs'
    … …  
    3736=== A more elaborate script
    3837
    39 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.
     38If you are 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.
    4039
    4140To solve this problem, use the following `.wsgi` file instead:
    … …  
    5352For 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.
    5453
    55 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:
     54If you have installed Trac and Python 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:
    5655
    5756{{{#!python
    … …  
    6463=== Recommended `trac.wsgi` script
    6564
    66 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).
    67 
     65A 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.
     66
     67If you are using Trac with multiple projects, you can specify their common parent directory using the `TRAC_ENV_PARENT_DIR` in the trac.wsgi in trac.wsgi: ''
     68
     69{{{#!python
     70  def application(environ, start_request):
     71      Add this to config when you have multiple projects                                             
     72      environ.setdefault('trac.env_parent_dir', '/usr/share/trac/projects') 
     73      ..
     74      ..
     75}}}
    6876
    6977== Mapping requests to the script
    7078
    71 After you've done preparing your .wsgi script, add the following to your Apache configuration file (`httpd.conf` for example).
     79After preparing your .wsgi script, add the following to your Apache configuration file, typically `httpd.conf`:
    7280
    7381{{{
    … …  
    95103}}}
    96104
    97 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.
     105In 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. After adding this configuration, restart Apache, and then it should work.
    98106
    99107To 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):
    … …  
    107115For 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.
    108116
    109 
    110117== Configuring Authentication
    111118
    112 We describe in the the following sections different methods for setting up authentication.
    113 
    114 See also [http://httpd.apache.org/docs/2.2/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
     119The following sections describe different methods for setting up authentication. See also [http://httpd.apache.org/docs/2.2/howto/auth.html Authentication, Authorization and Access Control] in the Apache guide.
    115120
    116121=== Using Basic Authentication ===
    117122
    118 The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program to create the password file:
     123The simplest way to enable authentication with Apache is to create a password file. Use the `htpasswd` program as follows:
    119124{{{
    120125$ htpasswd -c /somewhere/trac.htpasswd admin
    … …  
    124129}}}
    125130
    126 After the first user, you dont need the "-c" option anymore:
     131After the first user, you don't need the "-c" option anymore:
    127132{{{
    128133$ htpasswd /somewhere/trac.htpasswd john
    … …  
    136141After you've created the users, you can set their permissions using TracPermissions.
    137142
    138 Now, you'll need to enable authentication against the password file in the Apache configuration:
     143Now, you need to enable authentication against the password file in the Apache configuration:
    139144{{{
    140145<Location "/trac/login">
    … …  
    146151}}}
    147152
    148 If you're hosting multiple projects you can use the same password file for all of them:
     153If you are hosting multiple projects, you can use the same password file for all of them:
    149154{{{
    150155<LocationMatch "/trac/[^/]+/login">
    … …  
    162167For better security, it is recommended that you either enable SSL or at least use the “digest” authentication scheme instead of “Basic”.
    163168
    164 You'll have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
     169You have to create your `.htpasswd` file with the `htdigest` command instead of `htpasswd`, as follows:
    165170{{{
    166171# htdigest -c /somewhere/trac.htpasswd trac admin
    … …  
    189194}}}
    190195
    191 
    192196See also the [http://httpd.apache.org/docs/2.2/mod/mod_auth_digest.html mod_auth_digest] documentation.
    193197
    194198=== Using LDAP Authentication
    195199
    196 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)
    197 
    198 1. You need to load the following modules in Apache httpd.conf
     200Configuration for [http://httpd.apache.org/docs/2.2/mod/mod_ldap.html mod_ldap] authentication in Apache is more involved (httpd 2.2.x and OpenLDAP: slapd 2.3.19).
     201
     2021. You need to load the following modules in Apache httpd.conf:
    199203{{{
    200204LoadModule ldap_module modules/mod_ldap.so
    … …  
    219223}}}
    220224
    221 
    2222253. You can use the LDAP interface as a way to authenticate to a Microsoft Active Directory:
    223226
    224 
    225227Use the following as your LDAP URL:
    226228{{{
    … …  
    228230}}}
    229231
    230 You will also need to provide an account for Apache to use when checking
    231 credentials. As this password will be listed in plaintext in the
    232 config, you should be sure to use an account specifically for this task:
     232You will also need to provide an account for Apache to use when checking credentials. As this password will be listed in plaintext in the config, you need to use an account specifically for this task:
    233233{{{
    234234    AuthLDAPBindDN ldap-auth-user@example.com
    … …  
    255255}}}
    256256
    257 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.
    258 
    259 Note 2: You can also require the user be a member of a certain LDAP group, instead of
    260 just having a valid login:
     257Note 1: This is the case where the LDAP search will get around the multiple OUs, conecting to the Global Catalog Server portion of AD. Note 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.
     258
     259Note 2: You can also require the user be a member of a certain LDAP group, instead of just having a valid login:
    261260{{{
    262261    Require ldap-group CN=Trac Users,CN=Users,DC=example,DC=com
    … …  
    264263
    265264See also:
    266   - [http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap
    267    
     265 - [http://httpd.apache.org/docs/2.2/mod/mod_authnz_ldap.html mod_authnz_ldap], documentation for mod_authnz_ldap.   
    268266 - [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.
    269267 - [http://trac-hacks.org/wiki/LdapPlugin TracHacks:LdapPlugin] for storing TracPermissions in LDAP.
    … …  
    271269=== Using SSPI Authentication
    272270
    273 If you are using Apache on Windows, you can use mod_auth_sspi to provide
    274 single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the
    275 following to your !VirtualHost:
     271If you are using Apache on Windows, you can use mod_auth_sspi to provide single-sign-on. Download the module from the !SourceForge [http://sourceforge.net/projects/mod-auth-sspi/ mod-auth-sspi project] and then add the following to your !VirtualHost:
    276272{{{
    277273    <Location /trac/login>
    … …  
    288284}}}
    289285
    290 Using the above, usernames in Trac will be of the form `DOMAIN\username`, so
    291 you may have to re-add permissions and such. If you do not want the domain to
    292 be part of the username, set `SSPIOmitDomain On` instead.
     286Using the above, usernames in Trac will be of the form `DOMAIN\username`, so you may have to re-add permissions and such. If you do not want the domain to be part of the username, set `SSPIOmitDomain On` instead.
    293287
    294288Some common problems with SSPI authentication: [trac:#1055], [trac:#1168] and [trac:#3338].
    … …  
    324318=== Example: Apache/mod_wsgi with Basic Authentication, Trac being at the root of a virtual host
    325319
    326 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.
    327 
     320Per the mod_wsgi documentation linked to above, here is an example Apache configuration that:
     321 - serves the Trac instance from a virtualhost subdomain
     322 - uses Apache basic authentication for Trac authentication.
    328323
    329324If 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:
    … …  
    336331htpasswd htpasswd seconduser
    337332}}}
    338 (keep the file above your document root for security reasons)
    339 
    340 Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following contents:
     333Keep the file above your document root for security reasons.
     334
     335Create this file e.g. (ubuntu) `/etc/apache2/sites-enabled/trac.my-proj.my-site.org.conf` with the following content:
    341336
    342337{{{
    … …  
    363358Note: for subdomains to work you would probably also need to alter `/etc/hosts` and add A-Records to your host's DNS.
    364359
    365 
    366360== Troubleshooting
    367361
    368362=== Use a recent version
    369363
    370 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].
     364Please 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].
    371365
    372366''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''
    373367
    374 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).
     368If you plan to use `mod_wsgi` in embedded mode on Windows or with the MPM worker on Linux, then you will need version 0.3.4 or greater. See [trac:#10675] for details.
    375369
    376370=== Getting Trac to work nicely with SSPI and 'Require Group' ===
    377 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'.
    378 
    379 This WSGI script 'fixes' things, hope it helps:
     371
     372If you have 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 it is not working, your usernames in Trac probably look like 'DOMAIN\user' rather than 'user'.
     373
     374This WSGI script 'fixes' that:
    380375{{{#!python
    381376import os
    … …  
    391386}}}
    392387
    393 
    394388=== Trac with PostgreSQL ===
    395389
    396 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.
    397 
    398 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.
    399 
    400 But it's not necessary to edit the source of Trac, the following lines in `trac.wsgi` will also work:
     390When using the mod_wsgi adapter with multiple Trac instances and PostgreSQL (or MySQL?) as the database, the server ''may'' create a lot of open database connections and thus PostgreSQL processes.
     391
     392A somewhat brutal workaround is to disable connection pooling in Trac. This is done by setting `poolable = False` in `trac.db.postgres_backend` on the `PostgreSQLConnection` class.
     393
     394But it is not necessary to edit the source of Trac. The following lines in `trac.wsgi` will also work:
    401395
    402396{{{#!python
    … …  
    412406}}}
    413407
    414 Now Trac drops the connection after serving a page and the connection count on the database will be kept minimal.
     408Now Trac drops the connection after serving a page and the connection count on the database will be kept low.
    415409
    416410//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.//
    … …  
    420414For 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.
    421415
    422 
    423416----
    424 See also:  TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]
     417See also: TracGuide, TracInstall, [wiki:TracFastCgi FastCGI], [wiki:TracModPython ModPython], [trac:TracNginxRecipe TracNginxRecipe]