# Licensed to the Apache Software Foundation (ASF) under one
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# distributed with this work for additional information
# regarding copyright ownership. The ASF licenses this file
# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied. See the License for the
# specific language governing permissions and limitations
# under the License.
"""
Provides ScriptTask, a base class for implementing a command-line script that
can be run as a task.
To use, subclass ScriptTask and implement two methods::
class MyScript(ScriptTask):
@classmethod
def parser(cls):
'''Define and return an argparse.ArgumentParser instance'''
pass
@classmethod
def execute(cls, options):
'''Your main code goes here.'''
pass
To call as a script::
if __name__ == '__main__':
MyScript.main()
To call as a task::
# post the task with cmd-line-style args
MyScript.post('-p myproject --dry-run')
"""
import argparse
import logging
import shlex
import sys
from allura.lib.decorators import task
log = logging.getLogger(__name__)
class Writer(object):
def __init__(self, func):
self.func = func
def write(self, buf):
self.func(buf)
class ScriptTask(object):
"""Base class for a command-line script that is also executable as a task."""
class __metaclass__(type):
@property
def __doc__(cls):
return cls.parser().format_help()
def __new__(meta, classname, bases, classDict):
return task(type.__new__(meta, classname, bases, classDict))
def __new__(cls, arg_string):
cls._execute_task(arg_string)
@classmethod
def _execute_task(cls, arg_string):
try:
_stdout = sys.stdout
_stderr = sys.stderr
sys.stdout = Writer(log.info)
sys.stderr = Writer(log.error)
try:
options = cls.parser().parse_args(shlex.split(arg_string or ''))
except SystemExit:
raise Exception("Error parsing args: '%s'" % arg_string)
cls.execute(options)
finally:
sys.stdout = _stdout
sys.stderr = _stderr
@classmethod
def execute(cls, options):
"""User code goes here."""
pass
@classmethod
def parser(cls):
"""Return an argument parser appropriate for your script."""
return argparse.ArgumentParser(description="Default no-op parser")
@classmethod
def main(cls):
options = cls.parser().parse_args()
cls.execute(options)