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IMPORTANT NOTICE ================ I (@rubik), the current maintainer of Baker, am no longer able to maintain it. If someone wants to step in, contact me. History ======= Version 1.3 * Better Python 3 support. * Improved test coverage. * Fixed #22: *varargs are now displayed in command help. * Fixed annoying beavhior of *varargs help when no keyword arguments are present. Version 1.2 * Python 3 support! * Runs from Python 2.6 up to 3.2. * More unit tests. * Code coverage to 89%. * Single-letter arguments are now automatically added to shortopts. * Fixed #14: Unable to mix varargs and kwargs. Version 1.1 * ``baker.run()`` now prints the return value of the command function. * Command usage help now shows help for optional arguments. * Added options to ``baker.run()``. * Added ``baker.usage([commandname])``. * Added unit tests. * Fixed bugs. Overview ======== Baker lets you easily add a command line interface to your Python functions using a simple decorator, to create scripts with "sub-commands", similar to Django's ``manage.py``, ``svn``, ``hg``, etc.:: #!python import baker # An imaginary script full of useful Python functions @baker.command def set(name, value=None, overwrite=False): """Sets the value of a key in the database. If you don't specify a value, the named key is deleted. Overwriting a value may not be visible to all clients until the next full sync. """ db = get_database() if overwrite or name not in db: if value is None: db.delete(name) print "Deleted %s" % name else: db.set(name, value) print "Set %s to %s" % (name, value) else: print "Key exists!" @baker.command def get(name): "Prints the value of a key in the database." db = get_database() print db.get(name) baker.run() You can then run the script and use your function names and parameters as the command line interface, using ``optparse``-style options:: $ script.py set alfa bravo Set alfa to bravo $ script.py set --overwrite alfa charlie Set alfa to charlie $ script.py get alfa charlie $ script.py --help Available commands: get Prints the value of a key in the database. set Sets the value of a key in the database Use "script.py <command> --help" for individual command help. $ script.py set --help Usage: script.py set <name> [<value>] Sets the value of a key in the database. If you don't specify a value, the named key is deleted. Overwriting a value may not be visible to all clients until the next full sync. Options: --overwrite Arguments ========= Baker maps command line options to function parameters in the most natural way available. Bare arguments are used to fill in required parameters:: @baker.command def test(a, b, c): print "a=", a, "b=", b, "c=", c $ script.py test 1 2 3 a= 1 b= 2 c= 3 ``--option`` arguments are used to fill in keyword parameters. You can use ``--option value`` or ``--option=value``, as in optparse:: @baker.command def test(key="C"): print "In the key of:", key $ script.py test In the key of: C $ script.py test --key A In the key of: A $ script.py test --key=Gb In the key of: Gb Function parameters where the default is ``None`` are considered optional arguments and will be filled if extra arguments are available. Otherwise, extra bare arguments never fill in keyword parameters:: @baker.command def test(start, end=None, sortby="time"): print "start=", start, "end=", end, "sort=", sortby $ script.py --sortby name 1 start= 1 end= sortby= name $ script.py 1 2 start= 1 end= 2 sortby= time If a keyword parameter's default is an int or float, Baker will try to convert the option's string to the same type:: @baker.command def test(limit=10): print type(limit) $ script.py test --limit 10 <type 'int'> If the default of a parameter is a boolean, the corresponding command line option is a flag that sets the opposite of the default:: @baker.command def test(name, verbose=False): if verbose: print "Opening", name $ script.py test --verbose alfa Opening alfa If the function takes ``*`` and/or ``**`` parameters, any leftover arguments and options will fill them in. Parameter help ============== Baker lets you specify help for parameters in three ways. In the decorator:: @baker.command(params={"force": "Delete even if the file exists"}) def delete(filename, force=False): "Deletes a file." if force or not os.path.exists(filename): os.remove(filename) In Python 3.x, you can use parameter annotations to associate doc strings with parameters:: @baker.command def delete(filename, force:"Delete even if the file exists."=False): "Deletes a file." if force or not os.path.exists(filename): os.remove(filename) Baker can parse the function's docstring for Sphinx-style ``:param`` blocks:: @baker.command def delete(filename, force=False): """Deletes a file. :param force: Delete even if the file exists. """ if force or not os.path.exists(filename): os.remove(filename) Short options ============= To allow single-character short options (e.g. ``-v`` for ``--verbose``), use the ``shortopts`` keyword on the decorator:: @baker.command(shortopts={"verbose": "v"}, params={"verbose", "Spew lots"}) def test(verbose=False): pass $ script.py test --help Usage: script.py test Options: -v --verbose Spew lots You can group multiple short flag options together (``-xvc``). You can also optionally not put a space between a short option and its argument, for example ``-nCASE`` instead of ``-n CASE``. ``run()`` function ================== The ``run()`` function has a few useful options. * ``argv``: the list of options to parse. Default is ``sys.argv``. * ``main``: if True (the default), this function acts like the main function of the module -- it prints errors instead of raising exceptions, prints the return value of the command function, and exits with an error code on errors. * ``help_on_error``: if True, when an error occurs, automatically prints the usage help after the error message. Default is False. * ``outfile``, ``errorfile``, ``helpfile``: the files to use for output, errors, and usage help. Defaults are stdout, stderr, and stdout. * ``errorcode``: if main=True and this value is not 0, calls ``sys.exit()`` with this code in the event of an error ``usage()`` function ==================== Use the ``usage()`` function if you need to print the usage help programmatically:: # Print overall help baker.usage() # Print help for a command baker.usage("commandname") # Print to a file baker.usage("commandname", file=sys.stdout) Miscellaneous ============= Instead of ``baker.run()``, you can use ``baker.test()`` to print out how Baker will call your function based on the given command line. As in many UNIX command line utilities, if you specify a single hyphen (``-``) as a bare argument, any subsequent arguments will not parsed as options, even if they start with ``--``. Commands are automatically given the same name as the decorated function. To give a command a different name, use the ``name`` keyword on the decorator. This is especially useful when the command name you want isn't a valid Python identifier:: @baker.command(name="track-all") def trackall(): pass You can specify a "default" command that is used when the first argument to the script doesn't look like a command name:: @baker.command(default=True) def here(back=False): print "here! back=", back @baker.command def there(back=False): print "there! back=", back $ script.py --back here! back= True The ``baker`` module contains a ``Baker`` class you can instantiate if you don't want to use the global functions:: mybaker = baker.Baker() @mybaker.command def test(): print "hello" mybaker.run() About Baker =========== Created by Matt Chaput. Released under the `Apache 2.0 license <http://www.apache.org/licenses/LICENSE-2.0>`_ Please file bugs in the BitBucket issue tracker. http://bitbucket.org/mchaput/baker