Qgelm

cliffdemo

package containing several modules.</p><div class=„section“ id=„main-py“ readability=„61“> <h3>main.py</h3> <p>The main application is defined in

main.py

:</p> <div class=„highlight-default“><table class=„highlighttable“ readability=„9“><tr readability=„20“><td class=„linenos“ readability=„3“><div class=„linenodiv“ readability=„6“><pre> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35</pre></div></td><td class=„code“ readability=„12“><div class=„highlight“ readability=„24“><pre>import sys from cliff.app import App from cliff.commandmanager import CommandManager class DemoApp(App):

  def __init__(self):
      super(DemoApp, self).__init__(
          description='cliff demo app',
          version='0.1',
          command_manager=CommandManager('cliff.demo'),
          deferred_help=True,
          )
  def initialize_app(self, argv):
      self.LOG.debug('initialize_app')
  def prepare_to_run_command(self, cmd):
      self.LOG.debug('prepare_to_run_command %s', cmd.__class__.__name__)
  def clean_up(self, cmd, result, err):
      self.LOG.debug('clean_up %s', cmd.__class__.__name__)
      if err:
          self.LOG.debug('got an error: %s', err)

def main(argv=sys.argv[1:]):

  myapp = DemoApp()
  return myapp.run(argv)

if name == 'main':

  sys.exit(main(sys.argv[1:]))

</pre></div> </td></tr></table></div> <p>The

DemoApp

class inherits from

App

and overrides

__init__()

to set the program description and version number. It also passes a

CommandManager

instance configured to look for plugins in the

cliff.demo

namespace.</p> <p>The

initialize_app()

method of

DemoApp

will be invoked after the main program arguments are parsed, but before any command processing is performed and before the application enters interactive mode. This hook is intended for opening connections to remote web services, databases, etc. using arguments passed to the main application.</p> <p>The

prepare_to_run_command()

method of

DemoApp

will be invoked after a command is identified, but before the command is given its arguments and run. This hook is intended for pre-command validation or setup that must be repeated and cannot be handled by

initialize_app()

.</p> <p>The

clean_up()

method of

DemoApp

is invoked after a command runs. If the command raised an exception, the exception object is passed to

clean_up()

. Otherwise the

err

argument is

None

.</p> <p>The

main()

function defined in

main.py

is registered as a console script entry point so that

DemoApp

can be run from the command line (see the discussion of

setup.py

below).</p> </div><div class=„section“ id=„simple-py“ readability=„11“> <h3>simple.py</h3> <p>Two commands are defined in

simple.py

:</p> <div class=„highlight-default“><table class=„highlighttable“ readability=„4“><tr readability=„9“><td class=„linenos“ readability=„3“><div class=„linenodiv“ readability=„6“><pre> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24</pre></div></td><td class=„code“ readability=„7“><div class=„highlight“ readability=„13“><pre>import logging from cliff.command import Command class Simple(Command):

  "A simple command that prints a message."
  log = logging.getLogger(__name__)
  def take_action(self, parsed_args):
      self.log.info('sending greeting')
      self.log.debug('debugging')
      self.app.stdout.write('hi!\n')

class Error(Command):

  "Always raises an error"
  log = logging.getLogger(__name__)
  def take_action(self, parsed_args):
      self.log.info('causing error')
      raise RuntimeError('this is the expected exception')

</pre></div> </td></tr></table></div> <p>

Simple

demonstrates using logging to emit messages on the console at different verbose levels.</p> <div class=„highlight-default“ readability=„6“><div class=„highlight“ readability=„7“><pre>(.venv)$ cliffdemo simple sending greeting hi! (.venv)$ cliffdemo -v simple prepare_to_run_command Simple sending greeting debugging hi! clean_up Simple (.venv)$ cliffdemo -q simple hi! </pre></div> </div> <p>

Error

always raises a

RuntimeError

exception when it is invoked, and can be used to experiment with the error handling features of cliff.</p> <div class=„highlight-default“ readability=„17“><div class=„highlight“ readability=„32“><pre>(.venv)$ cliffdemo error causing error ERROR: this is the expected exception (.venv)$ cliffdemo -v error prepare_to_run_command Error causing error ERROR: this is the expected exception clean_up Error got an error: this is the expected exception (.venv)$ cliffdemo –debug error causing error this is the expected exception Traceback (most recent call last):

File ".../cliff/app.py", line 218, in run_subcommand
  result = cmd.run(parsed_args)
File ".../cliff/command.py", line 43, in run
  self.take_action(parsed_args)
File ".../demoapp/cliffdemo/simple.py", line 24, in take_action
  raise RuntimeError('this is the expected exception')

RuntimeError: this is the expected exception Traceback (most recent call last):

File "/Users/dhellmann/Envs/cliff/bin/cliffdemo", line 9, in &lt;module&gt;
  load_entry_point('cliffdemo==0.1', 'console_scripts', 'cliffdemo')()
File ".../demoapp/cliffdemo/main.py", line 33, in main
  return myapp.run(argv)
File ".../cliff/app.py", line 160, in run
  result = self.run_subcommand(remainder)
File ".../cliff/app.py", line 218, in run_subcommand
  result = cmd.run(parsed_args)
File ".../cliff/command.py", line 43, in run
  self.take_action(parsed_args)
File ".../demoapp/cliffdemo/simple.py", line 24, in take_action
  raise RuntimeError('this is the expected exception')

RuntimeError: this is the expected exception </pre></div> </div> </div><div class=„section“ id=„list-py“ readability=„10“> <h3>list.py</h3> <p>

list.py

includes a single command derived from <a class=„reference internal“ href=„https://docs.openstack.org/developer/cliff/classes.html#cliff.lister.Lister“ title=„cliff.lister.Lister“>

cliff.lister.Lister

</a> which prints a list of the files in the current directory.</p> <div class=„highlight-default“><table class=„highlighttable“ readability=„5“><tr readability=„11“><td class=„linenos“ readability=„3“><div class=„linenodiv“ readability=„6“><pre> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18</pre></div></td><td class=„code“ readability=„8“><div class=„highlight“ readability=„15“><pre>import logging import os from cliff.lister import Lister class Files(Lister):

  """Show a list of files in the current directory.
  The file name and size are printed by default.
  """
  log = logging.getLogger(__name__)
  def take_action(self, parsed_args):
      return (('Name', 'Size'),
              ((n, os.stat(n).st_size) for n in os.listdir('.'))
              )

</pre></div> </td></tr></table></div> <p>

Files

prepares the data, and

Lister

manages the output formatter and printing the data to the console.</p> <div class=„highlight-default“ readability=„10“><div class=„highlight“ readability=„15“><pre>(.venv)$ cliffdemo files +—————+——+

Name

Size

+—————+——+

build	136
cliffdemo.log	2546
Makefile	5569
source	408

+—————+——+ (.venv)$ cliffdemo files -f csv „Name“,„Size“ „build“,136 „cliffdemo.log“,2690 „Makefile“,5569 „source“,408 </pre></div> </div> </div><div class=„section“ id=„show-py“ readability=„10“> <h3>show.py</h3> <p>

show.py

includes a single command derived from <a class=„reference internal“ href=„https://docs.openstack.org/developer/cliff/classes.html#cliff.show.ShowOne“ title=„cliff.show.ShowOne“>

cliff.show.ShowOne

</a> which prints the properties of the named file.</p> <div class=„highlight-default“><table class=„highlighttable“ readability=„10“><tr readability=„23“><td class=„linenos“ readability=„3“><div class=„linenodiv“ readability=„6“><pre> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31</pre></div></td><td class=„code“ readability=„13“><div class=„highlight“ readability=„27“><pre>import logging import os from cliff.show import ShowOne class File(ShowOne):

  "Show details about a file"
  log = logging.getLogger(__name__)
  def get_parser(self, prog_name):
      parser = super(File, self).get_parser(prog_name)
      parser.add_argument('filename', nargs='?', default='.')
      return parser
  def take_action(self, parsed_args):
      stat_data = os.stat(parsed_args.filename)
      columns = ('Name',
                 'Size',
                 'UID',
                 'GID',
                 'Modified Time',
                 )
      data = (parsed_args.filename,
              stat_data.st_size,
              stat_data.st_uid,
              stat_data.st_gid,
              stat_data.st_mtime,
              )
      return (columns, data)

</pre></div> </td></tr></table></div> <p>

File

prepares the data, and

ShowOne

manages the output formatter and printing the data to the console.</p> <div class=„highlight-default“ readability=„7“><div class=„highlight“ readability=„9“><pre>(.venv)$ cliffdemo file setup.py +—————+————–+

Field

Value

+—————+————–+

Name	setup.py
Size	5825
UID	502
GID	20
Modified Time	1335569964.0

+—————+————–+ </pre></div> </div> </div><div class=„section“ id=„setup-py“ readability=„11“> <h3>setup.py</h3> <p>The demo application is packaged using <a class=„reference external“ href=„http://packages.python.org/distribute/“>distribute</a>, the modern implementation of setuptools.</p> <div class=„highlight-default“><table class=„highlighttable“ readability=„22“><tr readability=„48“><td class=„linenos“ readability=„4“><div class=„linenodiv“ readability=„7“><pre> 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67</pre></div></td><td class=„code“ readability=„24“><div class=„highlight“ readability=„51“><pre>#!/usr/bin/env python PROJECT = 'cliffdemo' # Change docs/sphinx/conf.py too! VERSION = '0.1' from setuptools import setup, find_packages try:

  long_description = open('README.rst', 'rt').read()

except IOError:

  long_description = ''

setup(

  name=PROJECT,
  version=VERSION,
  description='Demo app for cliff',
  long_description=long_description,
  author='Doug Hellmann',
  author_email='doug.hellmann@gmail.com',
  url='https://github.com/openstack/cliff',
  download_url='https://github.com/openstack/cliff/tarball/master',
  classifiers=['Development Status :: 3 - Alpha',
               'License :: OSI Approved :: Apache Software License',
               'Programming Language :: Python',
               'Programming Language :: Python :: 2',
               'Programming Language :: Python :: 2.7',
               'Programming Language :: Python :: 3',
               'Programming Language :: Python :: 3.2',
               'Intended Audience :: Developers',
               'Environment :: Console',
               ],
  platforms=['Any'],
  scripts=[],
  provides=[],
  install_requires=['cliff'],
  namespace_packages=[],
  packages=find_packages(),
  include_package_data=True,
  entry_points={
      'console_scripts': [
          'cliffdemo = cliffdemo.main:main'
      ],
      'cliff.demo': [
          'simple = cliffdemo.simple:Simple',
          'two_part = cliffdemo.simple:Simple',
          'error = cliffdemo.simple:Error',
          'list files = cliffdemo.list:Files',
          'files = cliffdemo.list:Files',
          'file = cliffdemo.show:File',
          'show file = cliffdemo.show:File',
          'unicode = cliffdemo.encoding:Encoding',
      ],
  },
  zip_safe=False,

) </pre></div> </td></tr></table></div> <p>The important parts of the packaging instructions are the

entry_points

settings. All of the commands are registered in the