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Command-Line Pyramid

Your Pyramid application can be controlled and inspected using a variety of command-line utilities. These utilities are documented in this chapter.

Displaying Matching Views for a Given URL

For a big application with several views, it can be hard to keep the view configuration details in your head, even if you defined all the views yourself. You can use the pviews command in a terminal window to print a summary of matching routes and views for a given URL in your application. The pviews command accepts two arguments. The first argument to pviews is the path to your application's .ini file and section name inside the .ini file which points to your application. This should be of the format config_file#section_name. The second argument is the URL to test for matching views. The section_name may be omitted; if it is, it's considered to be main.

Here is an example for a simple view configuration using traversal:

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$ $VENV/bin/pviews development.ini#tutorial /FrontPage

URL = /FrontPage

    context: <tutorial.models.Page object at 0xa12536c>
    view name:

    View:
    -----
    tutorial.views.view_page
    required permission = view

The output always has the requested URL at the top and below that all the views that matched with their view configuration details. In this example only one view matches, so there is just a single View section. For each matching view, the full code path to the associated view callable is shown, along with any permissions and predicates that are part of that view configuration.

A more complex configuration might generate something like this:

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$ $VENV/bin/pviews development.ini#shootout /about

URL = /about

    context: <shootout.models.RootFactory object at 0xa56668c>
    view name: about

    Route:
    ------
    route name: about
    route pattern: /about
    route path: /about
    subpath:
    route predicates (request method = GET)

        View:
        -----
        shootout.views.about_view
        required permission = view
        view predicates (request_param testing, header X/header)

    Route:
    ------
    route name: about_post
    route pattern: /about
    route path: /about
    subpath:
    route predicates (request method = POST)

        View:
        -----
        shootout.views.about_view_post
        required permission = view
        view predicates (request_param test)

        View:
        -----
        shootout.views.about_view_post2
        required permission = view
        view predicates (request_param test2)

In this case, we are dealing with a URL dispatch application. This specific URL has two matching routes. The matching route information is displayed first, followed by any views that are associated with that route. As you can see from the second matching route output, a route can be associated with more than one view.

For a URL that doesn't match any views, pviews will simply print out a Not found message.

The Interactive Shell

Once you've installed your program for development using setup.py develop, you can use an interactive Python shell to execute expressions in a Python environment exactly like the one that will be used when your application runs "for real". To do so, use the pshell command line utility.

The argument to pshell follows the format config_file#section_name where config_file is the path to your application's .ini file and section_name is the app section name inside the .ini file which points to your application. For example, if your application .ini file might have a [app:main] section that looks like so:

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[app:main]
use = egg:MyProject
pyramid.reload_templates = true
pyramid.debug_authorization = false
pyramid.debug_notfound = false
pyramid.debug_templates = true
pyramid.default_locale_name = en

If so, you can use the following command to invoke a debug shell using the name main as a section name:

$ $VENV/bin starter/development.ini#main
Python 2.6.5 (r265:79063, Apr 29 2010, 00:31:32)
[GCC 4.4.3] on linux2
Type "help" for more information.

Environment:
  app          The WSGI application.
  registry     Active Pyramid registry.
  request      Active request object.
  root         Root of the default resource tree.
  root_factory Default root factory used to create `root`.

>>> root
<myproject.resources.MyResource object at 0x445270>
>>> registry
<Registry myproject>
>>> registry.settings['pyramid.debug_notfound']
False
>>> from myproject.views import my_view
>>> from pyramid.request import Request
>>> r = Request.blank('/')
>>> my_view(r)
{'project': 'myproject'}

The WSGI application that is loaded will be available in the shell as the app global. Also, if the application that is loaded is the Pyramid app with no surrounding middleware, the root object returned by the default root factory, registry, and request will be available.

You can also simply rely on the main default section name by omitting any hash after the filename:

$ $VENV/bin/pshell starter/development.ini

Press Ctrl-D to exit the interactive shell (or Ctrl-Z on Windows).

Extending the Shell

It is convenient when using the interactive shell often to have some variables significant to your application already loaded as globals when you start the pshell. To facilitate this, pshell will look for a special [pshell] section in your INI file and expose the subsequent key/value pairs to the shell. Each key is a variable name that will be global within the pshell session; each value is a dotted Python name. If specified, the special key setup should be a dotted Python name pointing to a callable that accepts the dictionary of globals that will be loaded into the shell. This allows for some custom initializing code to be executed each time the pshell is run. The setup callable can also be specified from the commandline using the --setup option which will override the key in the INI file.

For example, you want to expose your model to the shell, along with the database session so that you can mutate the model on an actual database. Here, we'll assume your model is stored in the myapp.models package.

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[pshell]
setup = myapp.lib.pshell.setup
m = myapp.models
session = myapp.models.DBSession
t = transaction

By defining the setup callable, we will create the module myapp.lib.pshell containing a callable named setup that will receive the global environment before it is exposed to the shell. Here we mutate the environment's request as well as add a new value containing a WebTest version of the application to which we can easily submit requests.

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# myapp/lib/pshell.py
from webtest import TestApp

def setup(env):
    env['request'].host = 'www.example.com'
    env['request'].scheme = 'https'
    env['testapp'] = TestApp(env['app'])

When this INI file is loaded, the extra variables m, session and t will be available for use immediately. Since a setup callable was also specified, it is executed and a new variable testapp is exposed, and the request is configured to generate urls from the host http://www.example.com. For example:

$ $VENV/bin/pshell starter/development.ini
Python 2.6.5 (r265:79063, Apr 29 2010, 00:31:32)
[GCC 4.4.3] on linux2
Type "help" for more information.

Environment:
  app          The WSGI application.
  registry     Active Pyramid registry.
  request      Active request object.
  root         Root of the default resource tree.
  root_factory Default root factory used to create `root`.
  testapp      <webtest.TestApp object at ...>

Custom Variables:
  m            myapp.models
  session      myapp.models.DBSession
  t            transaction

>>> testapp.get('/')
<200 OK text/html body='<!DOCTYPE...l>\n'/3337>
>>> request.route_url('home')
'https://www.example.com/'

IPython or bpython

If you have IPython and/or bpython in the interpreter you use to invoke the pshell command, pshell will autodiscover and use the first one found, in this order: IPython, bpython, standard Python interpreter. However you could specifically invoke one of your choice with the -p choice or --python-shell choice option.

$ $VENV/bin/pshell -p ipython | bpython | python development.ini#MyProject

Displaying All Application Routes

You can use the proutes command in a terminal window to print a summary of routes related to your application. Much like the pshell command (see The Interactive Shell), the proutes command accepts one argument with the format config_file#section_name. The config_file is the path to your application's .ini file, and section_name is the app section name inside the .ini file which points to your application. By default, the section_name is main and can be omitted.

For example:

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$ $VENV/bin/proutes development.ini
Name            Pattern                        View
----            -------                        ----
home            /                              <function my_view>
home2           /                              <function my_view>
another         /another                       None
static/         static/*subpath                <static_view object>
catchall        /*subpath                      <function static_view>

proutes generates a table with three columns: Name, Pattern, and View. The items listed in the Name column are route names, the items listed in the Pattern column are route patterns, and the items listed in the View column are representations of the view callable that will be invoked when a request matches the associated route pattern. The view column may show None if no associated view callable could be found. If no routes are configured within your application, nothing will be printed to the console when proutes is executed.

Displaying "Tweens"

A tween is a bit of code that sits between the main Pyramid application request handler and the WSGI application which calls it. A user can get a representation of both the implicit tween ordering (the ordering specified by calls to pyramid.config.Configurator.add_tween()) and the explicit tween ordering (specified by the pyramid.tweens configuration setting) orderings using the ptweens command. Tween factories will show up represented by their standard Python dotted name in the ptweens output.

For example, here's the ptweens command run against a system configured without any explicit tweens:

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$ $VENV/bin/ptweens development.ini
"pyramid.tweens" config value NOT set (implicitly ordered tweens used)

Implicit Tween Chain

Position    Name                                                Alias
--------    ----                                                -----
-           -                                                   INGRESS
0           pyramid_debugtoolbar.toolbar.toolbar_tween_factory  pdbt
1           pyramid.tweens.excview_tween_factory                excview
-           -                                                   MAIN

Here's the ptweens command run against a system configured with explicit tweens defined in its development.ini file:

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$ ptweens development.ini
"pyramid.tweens" config value set (explicitly ordered tweens used)

Explicit Tween Chain (used)

Position    Name
--------    ----
-           INGRESS
0           starter.tween_factory2
1           starter.tween_factory1
2           pyramid.tweens.excview_tween_factory
-           MAIN

Implicit Tween Chain (not used)

Position    Name
--------    ----
-           INGRESS
0           pyramid_debugtoolbar.toolbar.toolbar_tween_factory
1           pyramid.tweens.excview_tween_factory
-           MAIN

Here's the application configuration section of the development.ini used by the above ptweens command which reports that the explicit tween chain is used:

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[app:main]
use = egg:starter
reload_templates = true
debug_authorization = false
debug_notfound = false
debug_routematch = false
debug_templates = true
default_locale_name = en
pyramid.include = pyramid_debugtoolbar
pyramid.tweens = starter.tween_factory2
                 starter.tween_factory1
                 pyramid.tweens.excview_tween_factory

See Registering Tweens for more information about tweens.

Invoking a Request

You can use the prequest command-line utility to send a request to your application and see the response body without starting a server.

There are two required arguments to prequest:

  • The config file/section: follows the format config_file#section_name where config_file is the path to your application's .ini file and section_name is the app section name inside the .ini file. The section_name is optional, it defaults to main. For example: development.ini.
  • The path: this should be the non-url-quoted path element of the URL to the resource you'd like to be rendered on the server. For example, /.

For example:

$ $VENV/bin/prequest development.ini /

This will print the body of the response to the console on which it was invoked.

Several options are supported by prequest. These should precede any config file name or URL.

prequest has a -d (aka --display-headers) option which prints the status and headers returned by the server before the output:

$ $VENV/bin/prequest -d development.ini /

This will print the status, then the headers, then the body of the response to the console.

You can add request header values by using the --header option:

$ $VENV/bin/prequest --header=Host:example.com development.ini /

Headers are added to the WSGI environment by converting them to their CGI/WSGI equivalents (e.g. Host=example.com will insert the HTTP_HOST header variable as the value example.com). Multiple --header options can be supplied. The special header value content-type sets the CONTENT_TYPE in the WSGI environment.

By default, prequest sends a GET request. You can change this by using the -m (aka --method) option. GET, HEAD, POST and DELETE are currently supported. When you use POST, the standard input of the prequest process is used as the POST body:

$ $VENV/bin/prequest -mPOST development.ini / < somefile

Using Custom Arguments to Python when Running p* Scripts

New in version 1.5.

Each of Pyramid's console scripts (pserve, pviews, etc) can be run directly using python -m, allowing custom arguments to be sent to the python interpreter at runtime. For example:

python -3 -m pyramid.scripts.pserve development.ini

Showing All Installed Distributions and their Versions

New in version 1.5.

You can use the pdistreport command to show the Pyramid version in use, the Python version in use, and all installed versions of Python distributions in your Python environment:

$ $VENV/bin/pdistreport
Pyramid version: 1.5dev
Platform Linux-3.2.0-51-generic-x86_64-with-debian-wheezy-sid
Packages:
  authapp 0.0
    /home/chrism/projects/foo/src/authapp
  beautifulsoup4 4.1.3
    /home/chrism/projects/foo/lib/python2.7/site-packages/beautifulsoup4-4.1.3-py2.7.egg
... more output ...

pdistreport takes no options. Its output is useful to paste into a pastebin when you are having problems and need someone with more familiarity with Python packaging and distribution than you have to look at your environment.

Writing a Script

All web applications are, at their hearts, systems which accept a request and return a response. When a request is accepted by a Pyramid application, the system receives state from the request which is later relied on by your application code. For example, one view callable may assume it's working against a request that has a request.matchdict of a particular composition, while another assumes a different composition of the matchdict.

In the meantime, it's convenient to be able to write a Python script that can work "in a Pyramid environment", for instance to update database tables used by your Pyramid application. But a "real" Pyramid environment doesn't have a completely static state independent of a request; your application (and Pyramid itself) is almost always reliant on being able to obtain information from a request. When you run a Python script that simply imports code from your application and tries to run it, there just is no request data, because there isn't any real web request. Therefore some parts of your application and some Pyramid APIs will not work.

For this reason, Pyramid makes it possible to run a script in an environment much like the environment produced when a particular request reaches your Pyramid application. This is achieved by using the pyramid.paster.bootstrap() command in the body of your script.

New in version 1.1: pyramid.paster.bootstrap()

In the simplest case, pyramid.paster.bootstrap() can be used with a single argument, which accepts the PasteDeploy .ini file representing Pyramid your application configuration as a single argument:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini')
print(env['request'].route_url('home'))

pyramid.paster.bootstrap() returns a dictionary containing framework-related information. This dictionary will always contain a request object as its request key.

The following keys are available in the env dictionary returned by pyramid.paster.bootstrap():

request

A pyramid.request.Request object implying the current request state for your script.

app

The WSGI application object generated by bootstrapping.

root

The resource root of your Pyramid application. This is an object generated by the root factory configured in your application.

registry

The application registry of your Pyramid application.

closer

A parameterless callable that can be used to pop an internal Pyramid threadlocal stack (used by pyramid.threadlocal.get_current_registry() and pyramid.threadlocal.get_current_request()) when your scripting job is finished.

Let's assume that the /path/to/my/development.ini file used in the example above looks like so:

[pipeline:main]
pipeline = translogger
           another

[filter:translogger]
filter_app_factory = egg:Paste#translogger
setup_console_handler = False
logger_name = wsgi

[app:another]
use = egg:MyProject

The configuration loaded by the above bootstrap example will use the configuration implied by the [pipeline:main] section of your configuration file by default. Specifying /path/to/my/development.ini is logically equivalent to specifying /path/to/my/development.ini#main. In this case, we'll be using a configuration that includes an app object which is wrapped in the Paste "translogger" middleware (which logs requests to the console).

You can also specify a particular section of the PasteDeploy .ini file to load instead of main:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini#another')
print(env['request'].route_url('home'))

The above example specifies the another app, pipeline, or composite section of your PasteDeploy configuration file. The app object present in the env dictionary returned by pyramid.paster.bootstrap() will be a Pyramid router.

Changing the Request

By default, Pyramid will generate a request object in the env dictionary for the URL http://localhost:80/. This means that any URLs generated by Pyramid during the execution of your script will be anchored here. This is generally not what you want.

So how do we make Pyramid generate the correct URLs?

Assuming that you have a route configured in your application like so:

config.add_route('verify', '/verify/{code}')

You need to inform the Pyramid environment that the WSGI application is handling requests from a certain base. For example, we want to simulate mounting our application at https://example.com/prefix, to ensure that the generated URLs are correct for our deployment. This can be done by either mutating the resulting request object, or more simply by constructing the desired request and passing it into bootstrap():

from pyramid.paster import bootstrap
from pyramid.request import Request

request = Request.blank('/', base_url='https://example.com/prefix')
env = bootstrap('/path/to/my/development.ini#another', request=request)
print(env['request'].application_url)
# will print 'https://example.com/prefix'

Now you can readily use Pyramid's APIs for generating URLs:

env['request'].route_url('verify', code='1337')
# will return 'https://example.com/prefix/verify/1337'

Cleanup

When your scripting logic finishes, it's good manners to call the closer callback:

from pyramid.paster import bootstrap
env = bootstrap('/path/to/my/development.ini')

# .. do stuff ...

env['closer']()

Setting Up Logging

By default, pyramid.paster.bootstrap() does not configure logging parameters present in the configuration file. If you'd like to configure logging based on [logger] and related sections in the configuration file, use the following command:

import pyramid.paster
pyramid.paster.setup_logging('/path/to/my/development.ini')

See Logging for more information on logging within Pyramid.

Making Your Script into a Console Script

A "console script" is setuptools terminology for a script that gets installed into the bin directory of a Python virtualenv (or "base" Python environment) when a distribution which houses that script is installed. Because it's installed into the bin directory of a virtualenv when the distribution is installed, it's a convenient way to package and distribute functionality that you can call from the command-line. It's often more convenient to create a console script than it is to create a .py script and instruct people to call it with the "right" Python interpreter. A console script generates a file that lives in bin, and when it's invoked it will always use the "right" Python environment, which means it will always be invoked in an environment where all the libraries it needs (such as Pyramid) are available.

In general, you can make your script into a console script by doing the following:

  • Use an existing distribution (such as one you've already created via pcreate) or create a new distribution that possesses at least one package or module. It should, within any module within the distribution, house a callable (usually a function) that takes no arguments and which runs any of the code you wish to run.
  • Add a [console_scripts] section to the entry_points argument of the distribution which creates a mapping between a script name and a dotted name representing the callable you added to your distribution.
  • Run setup.py develop, setup.py install, or easy_install to get your distribution reinstalled. When you reinstall your distribution, a file representing the script that you named in the last step will be in the bin directory of the virtualenv in which you installed the distribution. It will be executable. Invoking it from a terminal will execute your callable.

As an example, let's create some code that can be invoked by a console script that prints the deployment settings of a Pyramid application. To do so, we'll pretend you have a distribution with a package in it named myproject. Within this package, we'll pretend you've added a scripts.py module which contains the following code:

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# myproject.scripts module

import optparse
import sys
import textwrap

from pyramid.paster import bootstrap

def settings_show():
    description = """\
    Print the deployment settings for a Pyramid application.  Example:
    'show_settings deployment.ini'
    """
    usage = "usage: %prog config_uri"
    parser = optparse.OptionParser(
        usage=usage,
        description=textwrap.dedent(description)
        )
    parser.add_option(
        '-o', '--omit',
        dest='omit',
        metavar='PREFIX',
        type='string',
        action='append',
        help=("Omit settings which start with PREFIX (you can use this "
              "option multiple times)")
        )

    options, args = parser.parse_args(sys.argv[1:])
    if not len(args) >= 1:
        print('You must provide at least one argument')
        return 2
    config_uri = args[0]
    omit = options.omit
    if omit is None:
        omit = []
    env = bootstrap(config_uri)
    settings, closer = env['registry'].settings, env['closer']
    try:
        for k, v in settings.items():
            if any([k.startswith(x) for x in omit]):
                continue
            print('%-40s     %-20s' % (k, v))
    finally:
        closer()

This script uses the Python optparse module to allow us to make sense out of extra arguments passed to the script. It uses the pyramid.paster.bootstrap() function to get information about the application defined by a config file, and prints the deployment settings defined in that config file.

After adding this script to the package, you'll need to tell your distribution's setup.py about its existence. Within your distribution's top-level directory your setup.py file will look something like this:

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import os

from setuptools import setup, find_packages

here = os.path.abspath(os.path.dirname(__file__))
with open(os.path.join(here, 'README.txt')) as f:
    README = f.read()
with open(os.path.join(here, 'CHANGES.txt')) as f:
    CHANGES = f.read()

requires = ['pyramid', 'pyramid_debugtoolbar']

setup(name='MyProject',
      version='0.0',
      description='My project',
      long_description=README + '\n\n' +  CHANGES,
      classifiers=[
        "Programming Language :: Python",
        "Framework :: Pylons",
        "Topic :: Internet :: WWW/HTTP",
        "Topic :: Internet :: WWW/HTTP :: WSGI :: Application",
        ],
      author='',
      author_email='',
      url='',
      keywords='web pyramid pylons',
      packages=find_packages(),
      include_package_data=True,
      zip_safe=False,
      install_requires=requires,
      tests_require=requires,
      test_suite="myproject",
      entry_points = """\
      [paste.app_factory]
      main = myproject:main
      """,
      )

We're going to change the setup.py file to add an [console_scripts] section with in the entry_points string. Within this section, you should specify a scriptname = dotted.path.to:yourfunction line. For example:

[console_scripts]
show_settings = myproject.scripts:settings_show

The show_settings name will be the name of the script that is installed into bin. The colon (:) between myproject.scripts and settings_show above indicates that myproject.scripts is a Python module, and settings_show is the function in that module which contains the code you'd like to run as the result of someone invoking the show_settings script from their command line.

The result will be something like:

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import os

from setuptools import setup, find_packages

here = os.path.abspath(os.path.dirname(__file__))
with open(os.path.join(here, 'README.txt')) as f:
    README = f.read()
with open(os.path.join(here, 'CHANGES.txt')) as f:
    CHANGES = f.read()

requires = ['pyramid', 'pyramid_debugtoolbar']

setup(name='MyProject',
      version='0.0',
      description='My project',
      long_description=README + '\n\n' +  CHANGES,
      classifiers=[
        "Programming Language :: Python",
        "Framework :: Pylons",
        "Topic :: Internet :: WWW/HTTP",
        "Topic :: Internet :: WWW/HTTP :: WSGI :: Application",
        ],
      author='',
      author_email='',
      url='',
      keywords='web pyramid pylons',
      packages=find_packages(),
      include_package_data=True,
      zip_safe=False,
      install_requires=requires,
      tests_require=requires,
      test_suite="myproject",
      entry_points = """\
      [paste.app_factory]
      main = myproject:main
      [console_scripts]
      show_settings = myproject.scripts:settings_show
      """,
      )

Once you've done this, invoking $$VENV/bin/python setup.py develop will install a file named show_settings into the $somevirtualenv/bin directory with a small bit of Python code that points to your entry point. It will be executable. Running it without any arguments will print an error and exit. Running it with a single argument that is the path of a config file will print the settings. Running it with an --omit=foo argument will omit the settings that have keys that start with foo. Running it with two "omit" options (e.g. --omit=foo --omit=bar) will omit all settings that have keys that start with either foo or bar:

$ $VENV/bin/show_settings development.ini --omit=pyramid --omit=debugtoolbar
debug_routematch                             False
debug_templates                              True
reload_templates                             True
mako.directories                             []
debug_notfound                               False
default_locale_name                          en
reload_resources                             False
debug_authorization                          False
reload_assets                                False
prevent_http_cache                           False

Pyramid's pserve, pcreate, pshell, prequest, ptweens and other p* scripts are implemented as console scripts. When you invoke one of those, you are using a console script.