Environment Variables and `.ini` File Settings¶

Pyramid behavior can be configured through a combination of operating system environment variables and .ini configuration file application section settings. The meaning of the environment variables and the configuration file settings overlap.

Note

Where a configuration file setting exists with the same meaning as an environment variable, and both are present at application startup time, the environment variable setting takes precedence.

The term "configuration file setting name" refers to a key in the .ini configuration for your application. The configuration file setting names documented in this chapter are reserved for Pyramid use. You should not use them to indicate application-specific configuration settings.

Reloading Templates¶

When this value is true, templates are automatically reloaded whenever they are modified without restarting the application, so you can see changes to templates take effect immediately during development. This flag is meaningful to Chameleon and Mako templates, as well as most third-party template rendering extensions.

Environment Variable Name	Config File Setting Name
`PYRAMID_RELOAD_TEMPLATES`	`pyramid.reload_templates` or `reload_templates`

Reloading Assets¶

Don't cache any asset file data when this value is true.

See also

Debugging Authorization¶

Print view authorization failure and success information to stderr when this value is true.

Environment Variable Name	Config File Setting Name
`PYRAMID_DEBUG_AUTHORIZATION`	`pyramid.debug_authorization` or `debug_authorization`

Debugging Not Found Errors¶

Print view-related NotFound debug messages to stderr when this value is true.

See also

Debugging Route Matching¶

Print debugging messages related to url dispatch route matching when this value is true.

See also

Preventing HTTP Caching¶

Prevent the http_cache view configuration argument from having any effect globally in this process when this value is true. No HTTP caching-related response headers will be set by the Pyramid http_cache view configuration feature when this is true.

See also

Preventing Cache Busting¶

Prevent the cachebust static view configuration argument from having any effect globally in this process when this value is true. No cache buster will be configured or used when this is true.

New in version 1.6.

See also

Debugging All¶

Turns on all debug* settings.

Environment Variable Name	Config File Setting Name
`PYRAMID_DEBUG_ALL`	`pyramid.debug_all` or `debug_all`

Reloading All¶

Turns on all reload* settings.

Environment Variable Name	Config File Setting Name
`PYRAMID_RELOAD_ALL`	`pyramid.reload_all` or `reload_all`

Default Locale Name¶

The value supplied here is used as the default locale name when a locale negotiator is not registered.

Environment Variable Name	Config File Setting Name
`PYRAMID_DEFAULT_LOCALE_NAME`	`pyramid.default_locale_name` or `default_locale_name`

Including Packages¶

pyramid.includes instructs your application to include other packages. Using the setting is equivalent to using the pyramid.config.Configurator.include() method.

Config File Setting Name
`pyramid.includes`

The value assigned to pyramid.includes should be a sequence. The sequence can take several different forms.

It can be a string.

If it is a string, the package names can be separated by spaces:
```
package1 package2 package3
```
The package names can also be separated by carriage returns:
```
package1
package2
package3
```
It can be a Python list, where the values are strings:
```
['package1', 'package2', 'package3']
```

Each value in the sequence should be a dotted Python name.

`pyramid.includes` vs. `pyramid.config.Configurator.include()`¶

Two methods exist for including packages: pyramid.includes and pyramid.config.Configurator.include(). This section explains their equivalence.

Using PasteDeploy¶

Using the following pyramid.includes setting in the PasteDeploy .ini file in your application:

[app:main]
pyramid.includes = pyramid_debugtoolbar
                   pyramid_tm

Is equivalent to using the following statements in your configuration code:

from pyramid.config import Configurator

def main(global_config, **settings):
    config = Configurator(settings=settings)
    # ...
    config.include('pyramid_debugtoolbar')
    config.include('pyramid_tm')
    # ...

It is fine to use both or either form.

Plain Python¶

Using the following pyramid.includes setting in your plain-Python Pyramid application:

from pyramid.config import Configurator

if __name__ == '__main__':
    settings = {'pyramid.includes':'pyramid_debugtoolbar pyramid_tm'}
    config = Configurator(settings=settings)

Is equivalent to using the following statements in your configuration code:

from pyramid.config import Configurator

if __name__ == '__main__':
    settings = {}
    config = Configurator(settings=settings)
    config.include('pyramid_debugtoolbar')
    config.include('pyramid_tm')

It is fine to use both or either form.

Explicit Tween Configuration¶

This value allows you to perform explicit tween ordering in your configuration. Tweens are bits of code used by add-on authors to extend Pyramid. They form a chain, and require ordering.

Ideally you won't need to use the pyramid.tweens setting at all. Tweens are generally ordered and included "implicitly" when an add-on package which registers a tween is "included". Packages are included when you name a pyramid.includes setting in your configuration or when you call pyramid.config.Configurator.include().

Authors of included add-ons provide "implicit" tween configuration ordering hints to Pyramid when their packages are included. However, the implicit tween ordering is only best-effort. Pyramid will attempt to provide an implicit order of tweens as best it can using hints provided by add-on authors, but because it's only best-effort, if very precise tween ordering is required, the only surefire way to get it is to use an explicit tween order. You may be required to inspect your tween ordering (see ptweens: Displaying "Tweens") and add a pyramid.tweens configuration value at the behest of an add-on author.

Config File Setting Name
`pyramid.tweens`

The value assigned to pyramid.tweens should be a sequence. The sequence can take several different forms.

It can be a string.

If it is a string, the tween names can be separated by spaces:
```
pkg.tween_factory1 pkg.tween_factory2 pkg.tween_factory3
```
The tween names can also be separated by carriage returns:
```
pkg.tween_factory1
pkg.tween_factory2
pkg.tween_factory3
```

It can be a Python list, where the values are strings:

['pkg.tween_factory1', 'pkg.tween_factory2', 'pkg.tween_factory3']

Each value in the sequence should be a dotted Python name.

PasteDeploy Configuration vs. Plain-Python Configuration¶

Using the following pyramid.tweens setting in the PasteDeploy .ini file in your application:

[app:main]
pyramid.tweens = pyramid_debugtoolbar.toolbar.tween_factory
                 pyramid.tweens.excview_tween_factory
                 pyramid_tm.tm_tween_factory

Is equivalent to using the following statements in your configuration code:

from pyramid.config import Configurator

def main(global_config, **settings):
    settings['pyramid.tweens'] = [
        'pyramid_debugtoolbar.toolbar.tween_factory',
        'pyramid.tweebs.excview_tween_factory',
        'pyramid_tm.tm_tween_factory',
    ]
    config = Configurator(settings=settings)

It is fine to use both or either form.

Examples¶

Let's presume your configuration file is named MyProject.ini, and there is a section representing your application named [app:main] within the file that represents your Pyramid application. The configuration file settings documented in the above "Config File Setting Name" column would go in the [app:main] section. Here's an example of such a section:

[app:main]
use = egg:MyProject
pyramid.reload_templates = true
pyramid.debug_authorization = true

You can also use environment variables to accomplish the same purpose for settings documented as such. For example, you might start your Pyramid application using the following command line:

PYRAMID_DEBUG_AUTHORIZATION=1 PYRAMID_RELOAD_TEMPLATES=1 \
    $VENV/bin/pserve MyProject.ini

If you started your application this way, your Pyramid application would behave in the same manner as if you had placed the respective settings in the [app:main] section of your application's .ini file.

If you want to turn all debug settings (every setting that starts with pyramid.debug_) on in one fell swoop, you can use PYRAMID_DEBUG_ALL=1 as an environment variable setting or you may use pyramid.debug_all=true in the config file. Note that this does not affect settings that do not start with pyramid.debug_* such as pyramid.reload_templates.

If you want to turn all pyramid.reload settings (every setting that starts with pyramid.reload_) on in one fell swoop, you can use PYRAMID_RELOAD_ALL=1 as an environment variable setting or you may use pyramid.reload_all=true in the config file. Note that this does not affect settings that do not start with pyramid.reload_* such as pyramid.debug_notfound.

Note

Specifying configuration settings via environment variables is generally most useful during development, where you may wish to augment or override the more permanent settings in the configuration file. This is useful because many of the reload and debug settings may have performance or security (i.e., disclosure) implications that make them undesirable in a production environment.

Understanding the Distinction Between `reload_templates` and `reload_assets`¶

The difference between pyramid.reload_assets and pyramid.reload_templates is a bit subtle. Templates are themselves also treated by Pyramid as asset files (along with other static files), so the distinction can be confusing. It's helpful to read Overriding Assets for some context about assets in general.

When pyramid.reload_templates is true, Pyramid takes advantage of the underlying templating system's ability to check for file modifications to an individual template file. When pyramid.reload_templates is true, but pyramid.reload_assets is not true, the template filename returned by the pkg_resources package (used under the hood by asset resolution) is cached by Pyramid on the first request. Subsequent requests for the same template file will return a cached template filename. The underlying templating system checks for modifications to this particular file for every request. Setting pyramid.reload_templates to True doesn't affect performance dramatically (although it should still not be used in production because it has some effect).

However, when pyramid.reload_assets is true, Pyramid will not cache the template filename, meaning you can see the effect of changing the content of an overridden asset directory for templates without restarting the server after every change. Subsequent requests for the same template file may return different filenames based on the current state of overridden asset directories. Setting pyramid.reload_assets to True affects performance dramatically, slowing things down by an order of magnitude for each template rendering. However, it's convenient to enable when moving files around in overridden asset directories. pyramid.reload_assets makes the system very slow when templates are in use. Never set pyramid.reload_assets to True on a production system.

Adding a Custom Setting¶

From time to time, you may need to add a custom setting to your application. Here's how:

If you're using an .ini file, change the .ini file, adding the setting to the [app:foo] section representing your Pyramid application. For example:
```
[app:main]
# .. other settings
debug_frobnosticator = True
```
In the main() function that represents the place that your Pyramid WSGI application is created, anticipate that you'll be getting this key/value pair as a setting and do any type conversion necessary.

If you've done any type conversion of your custom value, reset the converted values into the settings dictionary before you pass the dictionary as settings to the Configurator. For example:
```
def main(global_config, **settings):
    # ...
    from pyramid.settings import asbool
    debug_frobnosticator = asbool(settings.get(
        'debug_frobnosticator', 'false'))
    settings['debug_frobnosticator'] = debug_frobnosticator
    config = Configurator(settings=settings)
```
Note

It's especially important that you mutate the settings dictionary with the converted version of the variable before passing it to the Configurator: the configurator makes a copy of settings, it doesn't use the one you pass directly.
When creating an includeme function that will be later added to your application's configuration you may access the settings dictionary through the instance of the Configurator that is passed into the function as its only argument. For Example:

def includeme(config):
    settings = config.registry.settings
    debug_frobnosticator = settings['debug_frobnosticator']

In the runtime code from where you need to access the new settings value, find the value in the registry.settings dictionary and use it. In view code (or any other code that has access to the request), the easiest way to do this is via request.registry.settings. For example:
```
settings = request.registry.settings
debug_frobnosticator = settings['debug_frobnosticator']
```
If you wish to use the value in code that does not have access to the request and you wish to use the value, you'll need to use the pyramid.threadlocal.get_current_registry() API to obtain the current registry, then ask for its settings attribute. For example:
```
registry = pyramid.threadlocal.get_current_registry()
settings = registry.settings
debug_frobnosticator = settings['debug_frobnosticator']
```

Environment Variables and `.ini` File Settings¶

Reloading Templates¶

Reloading Assets¶

Debugging Authorization¶

Debugging Not Found Errors¶

Debugging Route Matching¶

Preventing HTTP Caching¶

Preventing Cache Busting¶

Debugging All¶

Reloading All¶

Default Locale Name¶

Including Packages¶

`pyramid.includes` vs. `pyramid.config.Configurator.include()`¶

Using PasteDeploy¶

Plain Python¶

Explicit Tween Configuration¶

PasteDeploy Configuration vs. Plain-Python Configuration¶

Examples¶

Understanding the Distinction Between `reload_templates` and `reload_assets`¶

Adding a Custom Setting¶

Table of Contents

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This Page

Environment Variables and .ini File Settings¶

Reloading Templates¶

Reloading Assets¶

Debugging Authorization¶

Debugging Not Found Errors¶

Debugging Route Matching¶

Preventing HTTP Caching¶

Preventing Cache Busting¶

Debugging All¶

Reloading All¶

Default Locale Name¶

Including Packages¶

pyramid.includes vs. pyramid.config.Configurator.include()¶

Using PasteDeploy¶

Plain Python¶

Explicit Tween Configuration¶

PasteDeploy Configuration vs. Plain-Python Configuration¶

Examples¶

Understanding the Distinction Between reload_templates and reload_assets¶

Adding a Custom Setting¶

Environment Variables and `.ini` File Settings¶

`pyramid.includes` vs. `pyramid.config.Configurator.include()`¶

Understanding the Distinction Between `reload_templates` and `reload_assets`¶