"""
Base classes for writing management commands (named commands which can
be executed through ``django-admin.py`` or ``manage.py``).
"""
import os
import sys
from optparse import make_option,OptionParser
import django
from django.core.exceptions import ImproperlyConfigured
from django.core.management.color import color_style
from django.utils.encoding import smart_str
class CommandError(Exception):
"""
Exception class indicating a problem while executing a management
command.
If this exception is raised during the execution of a management
command, it will be caught and turned into a nicely-printed error
message to the appropriate output stream (i.e., stderr); as a
result, raising this exception (with a sensible description of the
error) is the preferred way to indicate that something has gone
wrong in the execution of a command.
"""
pass
def handle_default_options(options):
"""
Include any default options that all commands should accept here
so that ManagementUtility can handle them before searching for
user commands.
"""
if options.settings:
os.environ['DJANGO_SETTINGS_MODULE'] = options.settings
if options.pythonpath:
sys.path.insert(0, options.pythonpath)
class BaseCommand(object):
"""
The base class from which all management commands ultimately
derive.
Use this class if you want access to all of the mechanisms which
parse the command-line arguments and work out what code to call in
response; if you don't need to change any of that behavior,
consider using one of the subclasses defined in this file.
If you are interested in overriding/customizing various aspects of
the command-parsing and -execution behavior, the normal flow works
as follows:
1. ``django-admin.py`` or ``manage.py`` loads the command class
and calls its ``run_from_argv()`` method.
2. The ``run_from_argv()`` method calls ``create_parser()`` to get
an ``OptionParser`` for the arguments, parses them, performs
any environment changes requested by options like
``pythonpath``, and then calls the ``execute()`` method,
passing the parsed arguments.
3. The ``execute()`` method attempts to carry out the command by
calling the ``handle()`` method with the parsed arguments; any
output produced by ``handle()`` will be printed to standard
output and, if the command is intended to produce a block of
SQL statements, will be wrapped in ``BEGIN`` and ``COMMIT``.
4. If ``handle()`` raised a ``CommandError``, ``execute()`` will
instead print an error message to ``stderr``.
Thus, the ``handle()`` method is typically the starting point for
subclasses; many built-in commands and command types either place
all of their logic in ``handle()``, or perform some additional
parsing work in ``handle()`` and then delegate from it to more
specialized methods as needed.
Several attributes affect behavior at various steps along the way:
``args``
A string listing the arguments accepted by the command,
suitable for use in help messages; e.g., a command which takes
a list of application names might set this to '<appname
appname ...>'.
``can_import_settings``
A boolean indicating whether the command needs to be able to
import Django settings; if ``True``, ``execute()`` will verify
that this is possible before proceeding. Default value is
``True``.
``help``
A short description of the command, which will be printed in
help messages.
``option_list``
This is the list of ``optparse`` options which will be fed
into the command's ``OptionParser`` for parsing arguments.
``output_transaction``
A boolean indicating whether the command outputs SQL
statements; if ``True``, the output will automatically be
wrapped with ``BEGIN;`` and ``COMMIT;``. Default value is
``False``.
``requires_model_validation``
A boolean; if ``True``, validation of installed models will be
performed prior to executing the command. Default value is
``True``. To validate an individual application's models
rather than all applications' models, call
``self.validate(app)`` from ``handle()``, where ``app`` is the
application's Python module.
"""
# Metadata about this command.
option_list = (
make_option('-v', '--verbosity', action='store', dest='verbosity', default='1',
type='choice', choices=['0', '1', '2'],
help='Verbosity level; 0=minimal output, 1=normal output, 2=all output'),
make_option('--settings',
help='The Python path to a settings module, e.g. "myproject.settings.main". If this isn\'t provided, the DJANGO_SETTINGS_MODULE environment variable will be used.'),
make_option('--pythonpath',
help='A directory to add to the Python path, e.g. "/home/djangoprojects/myproject".'),
make_option('--traceback', action='store_true',
help='Print traceback on exception'),
)
help = ''
args = ''
# Configuration shortcuts that alter various logic.
can_import_settings = True
requires_model_validation = True
output_transaction = False # Whether to wrap the output in a "BEGIN; COMMIT;"
def __init__(self):
self.style = color_style()
def get_version(self):
"""
Return the Django version, which should be correct for all
built-in Django commands. User-supplied commands should
override this method.
"""
return django.get_version()
def usage(self, subcommand):
"""
Return a brief description of how to use this command, by
default from the attribute ``self.help``.
"""
usage = '%%prog %s [options] %s' % (subcommand, self.args)
if self.help:
return '%s\n\n%s' % (usage, self.help)
else:
return usage
def create_parser(self, prog_name, subcommand):
"""
Create and return the ``OptionParser`` which will be used to
parse the arguments to this command.
"""
return OptionParser(prog=prog_name,
usage=self.usage(subcommand),
version=self.get_version(),
option_list=self.option_list)
def print_help(self, prog_name, subcommand):
"""
Print the help message for this command, derived from
``self.usage()``.
"""
parser = self.create_parser(prog_name, subcommand)
parser.print_help()
def run_from_argv(self, argv):
"""
Set up any environment changes requested (e.g., Python path
and Django settings), then run this command.
"""
parser = self.create_parser(argv[0], argv[1])
options, args = parser.parse_args(argv[2:])
handle_default_options(options)
self.execute(*args, **options.__dict__)
def execute(self, *args, **options):
"""
Try to execute this command, performing model validation if
needed (as controlled by the attribute
``self.requires_model_validation``). If the command raises a
``CommandError``, intercept it and print it sensibly to
stderr.
"""
# Switch to English, because django-admin.py creates database content
# like permissions, and those shouldn't contain any translations.
# But only do this if we can assume we have a working settings file,
# because django.utils.translation requires settings.
if self.can_import_settings:
try:
from django.utils import translation
translation.activate('en-us')
except ImportError, e:
# If settings should be available, but aren't,
# raise the error and quit.
sys.stderr.write(smart_str(self.style.ERROR('Error: %s\n' % e)))
sys.exit(1)
try:
if self.requires_model_validation:
self.validate()
output = self.handle(*args, **options)
if output:
if self.output_transaction:
# This needs to be imported here, because it relies on settings.
from django.db import connection
if connection.ops.start_transaction_sql():
print self.style.SQL_KEYWORD(connection.ops.start_transaction_sql())
print output
if self.output_transaction:
print self.style.SQL_KEYWORD("COMMIT;")
except CommandError, e:
sys.stderr.write(smart_str(self.style.ERROR('Error: %s\n' % e)))
sys.exit(1)
def validate(self, app=None, display_num_errors=False):
"""
Validates the given app, raising CommandError for any errors.
If app is None, then this will validate all installed apps.
"""
from django.core.management.validation import get_validation_errors
try:
from cStringIO import StringIO
except ImportError:
from StringIO import StringIO
s = StringIO()
num_errors = get_validation_errors(s, app)
if num_errors:
s.seek(0)
error_text = s.read()
raise CommandError("One or more models did not validate:\n%s" % error_text)
if display_num_errors:
print "%s error%s found" % (num_errors, num_errors != 1 and 's' or '')
def handle(self, *args, **options):
"""
The actual logic of the command. Subclasses must implement
this method.
"""
raise NotImplementedError()
class AppCommand(BaseCommand):
"""
A management command which takes one or more installed application
names as arguments, and does something with each of them.
Rather than implementing ``handle()``, subclasses must implement
``handle_app()``, which will be called once for each application.
"""
args = '<appname appname ...>'
def handle(self, *app_labels, **options):
from django.db import models
if not app_labels:
raise CommandError('Enter at least one appname.')
try:
app_list = [models.get_app(app_label) for app_label in app_labels]
except (ImproperlyConfigured, ImportError), e:
raise CommandError("%s. Are you sure your INSTALLED_APPS setting is correct?" % e)
output = []
for app in app_list:
app_output = self.handle_app(app, **options)
if app_output:
output.append(app_output)
return '\n'.join(output)
def handle_app(self, app, **options):
"""
Perform the command's actions for ``app``, which will be the
Python module corresponding to an application name given on
the command line.
"""
raise NotImplementedError()
class LabelCommand(BaseCommand):
"""
A management command which takes one or more arbitrary arguments
(labels) on the command line, and does something with each of
them.
Rather than implementing ``handle()``, subclasses must implement
``handle_label()``, which will be called once for each label.
If the arguments should be names of installed applications, use
``AppCommand`` instead.
"""
args = '<label label ...>'
label = 'label'
def handle(self, *labels, **options):
if not labels:
raise CommandError('Enter at least one %s.' % self.label)
output = []
for label in labels:
label_output = self.handle_label(label, **options)
if label_output:
output.append(label_output)
return '\n'.join(output)
def handle_label(self, label, **options):
"""
Perform the command's actions for ``label``, which will be the
string as given on the command line.
"""
raise NotImplementedError()
class NoArgsCommand(BaseCommand):
"""
A command which takes no arguments on the command line.
Rather than implementing ``handle()``, subclasses must implement
``handle_noargs()``; ``handle()`` itself is overridden to ensure
no arguments are passed to the command.
Attempting to pass arguments will raise ``CommandError``.
"""
args = ''
def handle(self, *args, **options):
if args:
raise CommandError("Command doesn't accept any arguments")
return self.handle_noargs(**options)
def handle_noargs(self, **options):
"""
Perform this command's actions.
"""
raise NotImplementedError()
def copy_helper(style, app_or_project, name, directory, other_name=''):
"""
Copies either a Django application layout template or a Django project
layout template into the specified directory.
"""
# style -- A color style object (see django.core.management.color).
# app_or_project -- The string 'app' or 'project'.
# name -- The name of the application or project.
# directory -- The directory to which the layout template should be copied.
# other_name -- When copying an application layout, this should be the name
# of the project.
import re
import shutil
other = {'project': 'app', 'app': 'project'}[app_or_project]
if not re.search(r'^[_a-zA-Z]\w*$', name): # If it's not a valid directory name.
# Provide a smart error message, depending on the error.
if not re.search(r'^[_a-zA-Z]', name):
message = 'make sure the name begins with a letter or underscore'
else:
message = 'use only numbers, letters and underscores'
raise CommandError("%r is not a valid %s name. Please %s." % (name, app_or_project, message))
top_dir = os.path.join(directory, name)
try:
os.mkdir(top_dir)
except OSError, e:
raise CommandError(e)
# Determine where the app or project templates are. Use
# django.__path__[0] because we don't know into which directory
# django has been installed.
template_dir = os.path.join(django.__path__[0], 'conf', '%s_template' % app_or_project)
for d, subdirs, files in os.walk(template_dir):
relative_dir = d[len(template_dir)+1:].replace('%s_name' % app_or_project, name)
if relative_dir:
os.mkdir(os.path.join(top_dir, relative_dir))
for i, subdir in enumerate(subdirs):
if subdir.startswith('.'):
del subdirs[i]
for f in files:
if not f.endswith('.py'):
# Ignore .pyc, .pyo, .py.class etc, as they cause various
# breakages.
continue
path_old = os.path.join(d, f)
path_new = os.path.join(top_dir, relative_dir, f.replace('%s_name' % app_or_project, name))
fp_old = open(path_old, 'r')
fp_new = open(path_new, 'w')
fp_new.write(fp_old.read().replace('{{ %s_name }}' % app_or_project, name).replace('{{ %s_name }}' % other, other_name))
fp_old.close()
fp_new.close()
try:
shutil.copymode(path_old, path_new)
_make_writeable(path_new)
except OSError:
sys.stderr.write(style.NOTICE("Notice: Couldn't set permission bits on %s. You're probably using an uncommon filesystem setup. No problem.\n" % path_new))
def _make_writeable(filename):
"""
Make sure that the file is writeable. Useful if our source is
read-only.
"""
import stat
if sys.platform.startswith('java'):
# On Jython there is no os.access()
return
if not os.access(filename, os.W_OK):
st = os.stat(filename)
new_permissions = stat.S_IMODE(st.st_mode) | stat.S_IWUSR
os.chmod(filename, new_permissions)
|