Convenience functions for working with the Cmd module,
the BaseCommand class for constructing command line programmes,
and other command line related stuff.
*Latest release 20240422*:
* BaseCommandOptions.popopts: return the dict from BaseCommand.popopts().
* BaseCommand.apply_preargv: apply the default options supported by self.options.
* BaseCommandOptions.update(mapping) method, useful for dropping subcommand-specific defaults onto the options ahead of the local popopts() call.
## Class `BaseCommand`
A base class for handling nestable command lines.
This class provides the basic parse and dispatch mechanisms
for command lines.
To implement a command line
one instantiates a subclass of `BaseCommand`:
class MyCommand(BaseCommand):
GETOPT_SPEC = 'ab:c'
USAGE_FORMAT = r"""Usage: {cmd} [-a] [-b bvalue] [-c] [--] arguments...
-a Do it all.
-b But using bvalue.
-c The 'c' option!
"""
...
and provides either a `main` method if the command has no subcommands
or a suite of `cmd_`*subcommand* methods, one per subcommand.
Running a command is done by:
MyCommand(argv).run()
Modules which implement a command line mode generally look like this:
... imports etc ...
def main(argv=None, **run_kw):
""" The command line mode.
"""
return MyCommand(argv).run(**run_kw)
... other code ...
class MyCommand(BaseCommand):
... other code ...
if __name__ == '__main__':
sys.exit(main(sys.argv))
Instances have a `self.options` attribute on which optional
modes are set,
avoiding conflict with the attributes of `self`.
Subclasses with no subcommands
generally just implement a `main(argv)` method.
Subclasses with subcommands
should implement a `cmd_`*subcommand*`(argv)` instance method
for each subcommand.
If a subcommand is itself implemented using `BaseCommand`
then it can be a simple attribute:
cmd_subthing = SubThingCommand
Returning to methods, if there is a paragraph in the method docstring
commencing with `Usage:`
then that paragraph is incorporated automatically
into the main usage message.
Example:
def cmd_ls(self, argv):
""" Usage: {cmd} [paths...]
Emit a listing for the named paths.
Further docstring non-usage information here.
"""
... do the "ls" subcommand ...
The subclass is customised by overriding the following methods:
* `apply_opt(opt,val)`:
apply an individual getopt global command line option
to `self.options`.
* `apply_opts(opts)`:
apply the `opts` to `self.options`.
`opts` is an `(option,value)` sequence
as returned by `getopot.getopt`.
The default implementation iterates over these and calls `apply_opt`.
* `cmd_`*subcmd*`(argv)`:
if the command line options are followed by an argument
whose value is *subcmd*,
then the method `cmd_`*subcmd*`(subcmd_argv)`
will be called where `subcmd_argv` contains the command line arguments
following *subcmd*.
* `main(argv)`:
if there are no command line arguments after the options
or the first argument does not have a corresponding
`cmd_`*subcmd* method
then method `main(argv)`
will be called where `argv` contains the command line arguments.
* `run_context()`:
a context manager to provide setup or teardown actions
to occur before and after the command implementation respectively,
such as to open and close a database.
Editorial: why not arparse?
Primarily because when incorrectly invoked
an argparse command line prints the help/usage messgae
and aborts the whole programme with `SystemExit`.
But also, I find the whole argparse `add_argument` thing cumbersome.
*Method `BaseCommand.__init__(self, argv=None, *, cmd=None, options=None, **kw_options)`*:
Initialise the command line.
Raises `GetoptError` for unrecognised options.
Parameters:
* `argv`:
optional command line arguments
including the main command name if `cmd` is not specified.
The default is `sys.argv`.
The contents of `argv` are copied,
permitting desctructive parsing of `argv`.
* `cmd`:
optional keyword specifying the command name for context;
if this is not specified it is taken from `argv.pop(0)`.
* `options`:
an optional keyword providing object for command state and context.
If not specified a new `self.Options` instance
is allocated for use as `options`.
The default `Options` class is `BaseCommandOptions`,
a dataclass with some prefilled attributes and properties
to aid use later.
Other keyword arguments are applied to `self.options`
as attributes.
The `cmd` and `argv` parameters have some fiddly semantics for convenience.
There are 3 basic ways to initialise:
* `BaseCommand()`: `argv` comes from `sys.argv`
and the value for `cmd` is derived from `argv[0]`
* `BaseCommand(argv)`: `argv` is the complete command line
including the command name and the value for `cmd` is
derived from `argv[0]`
* `BaseCommand(argv, cmd=foo)`: `argv` is the command
arguments _after_ the command name and `cmd` is set to
`foo`
The command line arguments are parsed according to
the optional `GETOPT_SPEC` class attribute (default `''`).
If `getopt_spec` is not empty
then `apply_opts(opts)` is called
to apply the supplied options to the state
where `opts` is the return from `getopt.getopt(argv,getopt_spec)`.
After the option parse,
if the first command line argument *foo*
has a corresponding method `cmd_`*foo*
then that argument is removed from the start of `argv`
and `self.cmd_`*foo*`(argv,options,cmd=`*foo*`)` is called
and its value returned.
Otherwise `self.main(argv,options)` is called
and its value returned.
If the command implementation requires some setup or teardown
then this may be provided by the `run_context`
context manager method,
called with `cmd=`*subcmd* for subcommands
and with `cmd=None` for `main`.
*`BaseCommand.Options`*
*Method `BaseCommand.__init_subclass__()`*:
Update subclasses of `BaseCommand`.
Appends the usage message to the class docstring.
*Method `BaseCommand.apply_opt(self, opt, val)`*:
Handle an individual global command line option.
This default implementation raises a `RuntimeError`.
It only fires if `getopt` actually gathered arguments
and would imply that a `GETOPT_SPEC` was supplied
without an `apply_opt` or `apply_opts` method to implement the options.
*Method `BaseCommand.apply_opts(self, opts)`*:
Apply command line options.
Subclasses can override this
but it is usually easier to override `apply_opt(opt,val)`.
*Method `BaseCommand.apply_preargv(self, argv)`*:
Do any preparsing of `argv` before the subcommand/main-args.
Return the remaining arguments.
This default implementation applies the default options
supported by `self.options` (an instance of `self.Options`
class).
*Method `BaseCommand.cmd_help(argv)`*:
Usage: {cmd} [-l] [subcommand-names...]
Print help for subcommands.
This outputs the full help for the named subcommands,
or the short help for all subcommands if no names are specified.
-l Long help even if no subcommand-names provided.
*Method `BaseCommand.cmd_shell(self, argv)`*:
Usage: {cmd}
Run a command prompt via cmd.Cmd using this command's subcommands.
*Method `BaseCommand.cmdloop(intro=None)`*:
Use `cmd.Cmd` to run a command loop which calls the `cmd_`* methods.
*Method `BaseCommand.getopt_error_handler(cmd, options, e, usage, subcmd=None)`*:
The `getopt_error_handler` method
is used to control the handling of `GetoptError`s raised
during the command line parse
or during the `main` or `cmd_`*subcmd*` calls.
This default handler issues a warning containing the exception text,
prints the usage message to standard error,
and returns `True` to indicate that the error has been handled.
The handler is called with these parameters:
* `cmd`: the command name
* `options`: the `options` object
* `e`: the `GetoptError` exception
* `usage`: the command usage or `None` if this was not provided
* `subcmd`: optional subcommand name;
if not `None`, is the name of the subcommand which caused the error
It returns a true value if the exception is considered handled,
in which case the main `run` method returns 2.
It returns a false value if the exception is considered unhandled,
in which case the main `run` method reraises the `GetoptError`.
To let the exceptions out unhandled
this can be overridden with a method which just returns `False`.
Otherwise,
the handler may perform any suitable action
and return `True` to contain the exception
or `False` to cause the exception to be reraised.
*Method `BaseCommand.handle_signal(self, sig, frame, *, runstate: Optional[cs.resources.RunState] = <function <lambda> at 0x104df9f30>)`*:
The default signal handler, which cancels the default `RunState`.
*Method `BaseCommand.poparg(argv: List[str], *a, unpop_on_error=False)`*:
Pop the leading argument off `argv` and parse it.
Return the parsed argument.
Raises `getopt.GetoptError` on a missing or invalid argument.
This is expected to be used inside a `main` or `cmd_*`
command handler method or inside `apply_preargv`.
You can just use:
value = argv.pop(0)
but this method provides conversion and valuation
and a richer failure mode.
Parameters:
* `argv`: the argument list, which is modified in place with `argv.pop(0)`
* the argument list `argv` may be followed by some help text
and/or an argument parser function.
* `validate`: an optional function to validate the parsed value;
this should return a true value if valid,
or return a false value or raise a `ValueError` if invalid
* `unvalidated_message`: an optional message after `validate`
for values failing the validation
* `unpop_on_error`: optional keyword parameter, default `False`;
if true then push the argument back onto the front of `argv`
if it fails to parse; `GetoptError` is still raised
Typical use inside a `main` or `cmd_*` method might look like:
self.options.word = self.poparg(argv, int, "a count value")
self.options.word = self.poparg(
argv, int, "a count value",
lambda count: count > 0, "count should be positive")
Because it raises `GetoptError` on a bad argument
the normal usage message failure mode follows automatically.
Demonstration:
>>> argv = ['word', '3', 'nine', '4']
>>> BaseCommand.poparg(argv, "word to process")
'word'
>>> BaseCommand.poparg(argv, int, "count value")
3
>>> BaseCommand.poparg(argv, float, "length")
Traceback (most recent call last):
...
getopt.GetoptError: length 'nine': float('nine'): could not convert string to float: 'nine'
>>> BaseCommand.poparg(argv, float, "width", lambda width: width > 5)
Traceback (most recent call last):
...
getopt.GetoptError: width '4': invalid value
>>> BaseCommand.poparg(argv, float, "length")
Traceback (most recent call last):
...
getopt.GetoptError: length: missing argument
>>> argv = ['-5', 'zz']
>>> BaseCommand.poparg(argv, float, "size", lambda f: f>0, "size should be >0")
Traceback (most recent call last):
...
getopt.GetoptError: size '-5': size should be >0
>>> argv # -5 was still consumed
['zz']
>>> BaseCommand.poparg(argv, float, "size2", unpop_on_error=True)
Traceback (most recent call last):
...
getopt.GetoptError: size2 'zz': float('zz'): could not convert string to float: 'zz'
>>> argv # zz was pushed back
['zz']
*Method `BaseCommand.popopts(argv, attrfor=None, **opt_specs)`*:
Parse option switches from `argv`, a list of command line strings
with leading option switches.
Modify `argv` in place and return a dict mapping switch names to values.
The optional positional argument `attrfor`
may supply an object whose attributes may be set by the options,
for example:
def cmd_foo(self, argv):
self.popopts(argv, self.options, a='all', j_=('jobs', int))
... use self.options.jobs etc ...
The expected options are specified by the keyword parameters
in `opt_specs`:
* options not starting with a letter may be preceeded by an underscore
to allow use in the parameter list, for example `_1='once'`
for a `-1` option setting the `once` option name
* a single letter name specifies a short option
and a multiletter name specifies a long option
* options requiring an argument have a trailing underscore
* options not requiring an argument normally imply a value
of `True`; if their synonym commences with a dash they will
imply a value of `False`, for example `n='dry_run',y='-dry_run'`
The `BaseCommandOptions` class provides a `popopts` method
which is a shim for this method with `attrfor=self` i.e.
the options object.
So common use in a command method usually looks like this:
class SomeCommand(BaseCommand):
def cmd_foo(self, argv):
options = self.options
# accept a -j or --jobs options
options.popopts(argv, jobs=1, j='jobs')
print("jobs =", options.jobs)
The `self.options` object is preprovided as an instance of
the `self.Options` class, which is `BaseCommandOptions` by
default. This presupplies support for some basic options
like `-v` for "verbose" and so forth, and a subcommand
need not describe these in a call to `self.options.popopts()`.
Example:
>>> import os.path
>>> from typing import Optional
>>> @dataclass
... class DemoOptions(BaseCommandOptions):
... all: bool = False
... jobs: int = 1
... number: int = 0
... once: bool = False
... path: Optional[str] = None
... trace_exec: bool = False
...
>>> options = DemoOptions()
>>> argv = ['-1', '-v', '-y', '-j4', '--path=/foo', 'bah', '-x']
>>> opt_dict = options.popopts(
... argv,
... _1='once',
... a='all',
... j_=('jobs',int),
... x='-trace_exec',
... y='-dry_run',
... dry_run=None,
... path_=(str, os.path.isabs, 'not an absolute path'),
... verbose=None,
... )
>>> opt_dict
{'once': True, 'verbose': True, 'dry_run': False, 'jobs': 4, 'path': '/foo'}
>>> options # doctest: +ELLIPSIS
DemoOptions(cmd=None, dry_run=False, force=False, quiet=False, runstate_signals=(...), verbose=True, all=False, jobs=4, number=0, once=True, path='/foo', trace_exec=False)
*Method `BaseCommand.repl(self, *argv, banner=None, local=None)`*:
Run an interactive Python prompt with some predefined local names.
Aka REPL (Read Evaluate Print Loop).
Parameters:
* `argv`: any notional command line arguments
* `banner`: optional banner string
* `local`: optional local names mapping
The default `local` mapping is a `dict` containing:
* `argv`: from `argv`
* `options`: from `self.options`
* `self`: from `self`
* the attributes of `options`
* the attributes of `self`
This is not presented automatically as a subcommand, but
commands wishing such a command should provide something
like this:
def cmd_repl(self, argv):
""" Usage: {cmd}
Run an interactive Python prompt with some predefined local names.
"""
return self.repl(*argv)
*Method `BaseCommand.run(self, **kw_options)`*:
Run a command.
Returns the exit status of the command.
May raise `GetoptError` from subcommands.
Any keyword arguments are used to override `self.options` attributes
for the duration of the run,
for example to presupply a shared `Upd` from an outer context.
If the first command line argument *foo*
has a corresponding method `cmd_`*foo*
then that argument is removed from the start of `argv`
and `self.cmd_`*foo*`(cmd=`*foo*`)` is called
and its value returned.
Otherwise `self.main(argv)` is called
and its value returned.
If the command implementation requires some setup or teardown
then this may be provided by the `run_context()`
context manager method.
*Method `BaseCommand.run_context(*a, upd: Optional[cs.upd.Upd] = <function uses_upd.<locals>.<lambda> at 0x104cea3b0>, **kw)`*:
The context manager which surrounds `main` or `cmd_`*subcmd*.
This default does several things, and subclasses should
override it like this:
@contextmanager
def run_context(self):
with super().run_context():
try:
... subclass context setup ...
yield
finally:
... any unconditional cleanup ...
*Method `BaseCommand.subcommand_usage_text(subcmd, usage_format_mapping=None, short=False)`*:
Return the usage text for a subcommand.
Parameters:
* `subcmd`: the subcommand name
* `short`: just include the first line of the usage message,
intented for when there are many subcommands
*Method `BaseCommand.subcommands()`*:
Return a mapping of subcommand names to subcommand specifications
for class attributes which commence with `cls.SUBCOMMAND_METHOD_PREFIX`
by default `'cmd_'`.
*Method `BaseCommand.usage_text(*, cmd=None, format_mapping=None, subcmd=None, short=False)`*:
Compute the "Usage:" message for this class
from the top level `USAGE_FORMAT`
and the `'Usage:'`-containing docstrings of its `cmd_*` methods.
Parameters:
* `cmd`: optional command name, default derived from the class name
* `format_mapping`: an optional format mapping for filling
in format strings in the usage text
* `subcmd`: constrain the usage to a particular subcommand named `subcmd`;
this is used to produce a shorter usage for subcommand usage failures
## Class `BaseCommandCmd(cmd.Cmd)`
A `cmd.Cmd` subclass used to provide interactive use of a
command's subcommands.
The `BaseCommand.cmdloop()` class method instantiates an
instance of this cand calls its `.cmdloop()` method
i.e. `cmd.Cmd.cmdloop`.
## Class `BaseCommandOptions(cs.threads.HasThreadState)`
A base class for the `BaseCommand` `options` object.
This is the default class for the `self.options` object
available during `BaseCommand.run()`,
and available as the `BaseCommand.Options` attribute.
Any keyword arguments are applied as field updates to the instance.
It comes prefilled with:
* `.dry_run=False`
* `.force=False`
* `.quiet=False`
* `.verbose=False`
and a `.doit` property which is the inverse of `.dry_run`.
It is recommended that if ``BaseCommand` subclasses use a
different type for their `Options` that it should be a
subclass of `BaseCommandOptions`.
Since `BaseCommandOptions` is a data class, this typically looks like:
@dataclass
class Options(BaseCommand.Options):
... optional extra fields etc ...
*Method `BaseCommandOptions.__call__(self, **updates)`*:
Calling the options object returns a context manager whose
value is a shallow copy of the options with any `suboptions` applied.
Example showing the semantics:
>>> from cs.cmdutils import BaseCommandOptions
>>> @dataclass
... class DemoOptions(BaseCommandOptions):
... x: int = 0
...
>>> options = DemoOptions(x=1)
>>> assert options.x == 1
>>> assert not options.verbose
>>> with options(verbose=True) as subopts:
... assert options is not subopts
... assert options.x == 1
... assert not options.verbose
... assert subopts.x == 1
... assert subopts.verbose
...
>>> assert options.x == 1
>>> assert not options.verbose
*Method `BaseCommandOptions.copy(self, **updates)`*:
Return a new instance of `BaseCommandOptions` (well, `type(self)`)
which is a shallow copy of the public attributes from `self.__dict__`.
Any keyword arguments are applied as attribute updates to the copy.
*Property `BaseCommandOptions.doit`*:
I usually use a `doit` flag,
the inverse of `dry_run`.
*`BaseCommandOptions.perthread_state`*
*Method `BaseCommandOptions.popopts(self, argv, **opt_specs)`*:
Convenience method to appply `BaseCommand.popopts` to the options (`self`).
Example for a `BaseCommand` `cmd_foo` method:
def cmd_foo(self, argv):
self.options.popopts(
c_='config',
l='long',
x='trace',
)
if self.options.dry_run:
print("dry run!")
The class attribute `COMMON_OPT_SPECS` is a mapping of
options which are always supported. `BaseCommandOptions`
has: `COMMON_OPT_SPECS={'n': 'dry_run', 'q': 'quiet', 'v': 'verbose'}`.
A subclass with more common options might extend this like so,
from `cs.hashindex`:
COMMON_OPT_SPECS = dict(
e='ssh_exe',
h_='hashname',
H_='hashindex_exe',
**BaseCommand.Options.COMMON_OPT_SPECS,
)
*Method `BaseCommandOptions.update(self, **updates)`*:
Modify the options in place with the mapping `updates`.
It would be more normal to call the options in a `with` statement
as shown for `__call__`.
## Function `docmd(dofunc)`
Decorator for `cmd.Cmd` subclass methods
to supply some basic quality of service.
This decorator:
- wraps the function call in a `cs.pfx.Pfx` for context
- intercepts `getopt.GetoptError`s, issues a `warning`
and runs `self.do_help` with the method name,
then returns `None`
- intercepts other `Exception`s,
issues an `exception` log message
and returns `None`
The intended use is to decorate `cmd.Cmd` `do_`* methods:
from cmd import Cmd
from cs.cmdutils import docmd
...
class MyCmd(Cmd):
@docmd
def do_something(...):
... do something ...
## Function `uses_cmd_options(func, cls=<class 'cs.cmdutils.BaseCommandOptions'>, options_param_name='options')`
A decorator to provide a default parameter containing the
prevailing `BaseCommandOptions` instance as the `options` keyword
argument, using the `cs.deco.default_params` decorator factory.
This allows functions to utilitse global options set by a
command such as `options.dry_run` or `options.verbose` without
the tedious plumbing through the entire call stack.
Parameters:
* `cls`: the `BaseCommandOptions` or `BaseCommand` class,
default `BaseCommandOptions`. If a `BaseCommand` subclass is
provided its `cls.Options` class is used.
* `options_param_name`: the parameter name to provide, default `options`
Examples:
@uses_cmd_options
def f(x,*,options):
""" Run directly from the prevailing options. """
if options.verbose:
print("doing f with x =", x)
....
@uses_cmd_options
def f(x,*,verbose=None,options):
""" Get defaults from the prevailing options. """
if verbose is None:
verbose = options.verbose
if verbose:
print("doing f with x =", x)
....
# Release Log
*Release 20240422*:
* BaseCommandOptions.popopts: return the dict from BaseCommand.popopts().
* BaseCommand.apply_preargv: apply the default options supported by self.options.
* BaseCommandOptions.update(mapping) method, useful for dropping subcommand-specific defaults onto the options ahead of the local popopts() call.
*Release 20240412*:
* BaseCommand.run_context: do not store .upd and .runstate on the options (it confuses options in subcommands and we have @uses_runstate and @uses_upd forthis anyway these days).
* BaseCommand.run_context: catch SIGQUIT, present the default handler as BaseCommand.handle_signal.
*Release 20240316*:
* New @uses_cmd_options decorator to provide an "options" parameter being the prevailing BaseCommandOptions instance.
* BaseCommandOptions.popopts: get common options from BaseCommandOptions.COMMON_OPT_SPECS.
*Release 20240211*:
* Include the first sentence of the subcommand description in the short help.
* BaseCommandOptions: move the runstate_signals into this directly.
* BaseCommand: move the run() options stuff into run_context() and have it work on a copy of the original options.
* BaseCommandCmd: implement get_names(), provide docstrings for the do_* attributes, thus help.
* BaseCommand.run_context: make runstate and upd keyword only parameters.
*Release 20240201*:
* BaseCommand.run: catch CancellationError and return 1.
* BaseCommandCmd.__getattr__: recognise EOF, exit and quit to terminate the cmdloop.
*Release 20231129*:
BaseCommandOptions: define a runstate field.
*Release 20230703*:
Small internal changes.
*Release 20230612*:
* BaseCommand.cmdloop: fix intro parameter.
* Other small fixes.
*Release 20230407*:
* BaseCommand: use @uses_runstate when preparing the command, store as self.options.runstate.
* Make BaseCommandOptions a data class.
* Drop any pretence at python 2 support, we're long past that.
* BaseCommand: new cmdloop method to run a cmd.Cmd instance to run subcommand interactively.
* BaseCommand: rename shell to repl, add cmd_shell to call cmdloop().
* Drop BaseCommand.apply_defaults in favour of the Options dataclass.
* BaseCommand: do setup_logging before initiating the Options instance.
*Release 20230212*:
* BaseCommand.run_context: update RunState support.
* BaseCommand.run_context: always be having an self.options.upd.
*Release 20230211*:
BaseCommand: new shell() method to present an interactive Python prompt for use by subclasses cmd_shell method if desired.
*Release 20221228*:
Move a lot of the context logic from BaseCommand.run to BaseCommand.run_context, which now must be correctly overridden in subclasses.
*Release 20220918*:
* BaseCommand.run_context: expand default signals to include SIGHUP, expose as BaseCommand.DEFAULT_SIGNALS.
* BaseCommand.run: pass in the subclass handle_signal method if present.
*Release 20220626*:
* BaseCommand.poparg: fix positional argument handling.
* BaseCommand.poparg: new unpop_on_error=False parameter to support pushing a bad argument back onto the front of the argument list.
*Release 20220606*:
BaseCommand.run: remove the Upd bodge, too annoying, now fixed in cs.upd I believe.
*Release 20220605*:
* BaseCommand: new popopts(argv,...) compact getopt wrapper.
* BaseCommand: new poparg(argv,...) compact validating argument consumer.
* BaseCommand: drop run_argv, provided no utility.
* BaseCommand.run: get the RunState signal list from self.options.runstate_signals.
* BaseCommand.apply_opts: support multiple individual options raising GetoptError, as I hate commands which abort at the first bad option.
* Assorted other small things.
*Release 20220429*:
* BaseCommand: fold dots in argv[0] into underscores, supports subcommands like "setup.py".
* BaseCommand: new popargv(argv[,help_text[,parse[,validate[,unvalidated_message]]]]) helper class method.
* BaseCommand: accept dashed-form of the underscored_form subcommand name.
* BaseCommand: new self.options.runstate_signals=SIGINT,SIGTERM specifying singals to catch-and-cancel, shuffle run() context managers.
*Release 20220318*:
BaseCommand.__init__: handle main() method in the New Scheme.
*Release 20220315*:
_BaseSubCommand.__init__: hook in the class USAGE_KEYWORDS for methods.
*Release 20220311*:
BaseCommand: big refactor of subcommand internals and make the "cmd_foo=FooCommand" implementation work properly.
*Release 20211208*:
BaseCommand: better handle an unknown subcommand.
*Release 20210927*:
* Usage: show only the per subcommand usage for in-subcommand GetoptError.
* Usage: show terse usage when the subcommand cannot be recognised.
* Usage: support bare -h, -help, --help.
*Release 20210913*:
New BaseCommand.apply_preargv method to gather special arguments before subcommands.
*Release 20210906*:
* BaseCommand.cmd_help: bugfix obsolete parameter list.
* BaseCommand.SUBCOMMAND_ARGV_DEFAULT: support a single str value, turn into list.
*Release 20210809*:
Bugfix BaseCommand.cmd_help for modern API.
*Release 20210731*:
* BaseCommand.run: apply optional keyword arguments to self.options during the run.
* Look for self.SUBCOMMAND_ARGV_DEFAULT if no subcommand is supplied.
* Bugfix case for "main" method and no "cmd_*" methods.
* Bugfix BaseCommand.cmd_help.
*Release 20210420*:
* BaseCommand.getopt_error_handler: replace error print() with warning().
* Docstring improvements.
*Release 20210407.1*:
BaseCommand: bugfix for __init_subclass__ docstring update.
*Release 20210407*:
* BaseCommand.__init_subclass__: behave sanely if the subclass has no initial __doc__.
* BaseCommand: new .run_argv convenience method, obviates the "def main" boilerplate.
*Release 20210404*:
BaseCommand subclasses: automatically add the main usage message to the subclass docstring.
*Release 20210306*:
* BREAKING CHANGE: rework BaseCommand as a more normal class instantiated with argv and with most methods being instance methods, getting the former `options` parameter from self.options.
* BaseCommand: provide default `apply_opt` and `apply_opts` methods; subclasses will generally just override the former.
*Release 20210123*:
BaseCommand: propagate the format mapping (cmd, USAGE_KEYWORDS) to the subusage generation.
*Release 20201102*:
* BaseCommand.cmd_help: supply usage only for "all commands", full docstring for specified commands.
* BaseCommand: honour presupplied options.log_level.
* BaseCommand.usage_text: handle missing USAGE_FORMAT better.
* BaseCommand.run: provide options.upd.
* BaseCommand subclasses may now override BaseCommand.OPTIONS_CLASS (default SimpleNamespace) in order to provide convenience methods on the options.
* BaseCommand.run: separate variable for subcmd with dash translated to underscore to match method names.
* Minor fixes.
*Release 20200615*:
BaseCommand.usage_text: do not mention the "help" command if it is the only subcommand (it won't be available if there are no other subcommands).
*Release 20200521.1*:
Fix DISTINFO.install_requires.
*Release 20200521*:
* BaseCommand.run: support using BaseCommand subclasses as cmd_* names to make it easy to nest BaseCommands.
* BaseCommand: new hack_postopts_argv method called after parsing the main command line options, for inferring subcommands or the like.
* BaseCommand: extract "Usage:" paragraphs from subcommand method docstrings to build the main usage message.
* BaseCommand: new cmd_help default command.
* Assorted bugfixes and small improvements.
*Release 20200318*:
* BaseCommand.run: make argv optional, get additional usage keywords from self.USAGE_KEYWORDS.
* @BaseCommand.add_usage_to_docstring: honour cls.USAGE_KEYWORDS.
* BaseCommand: do not require GETOPT_SPEC for commands with no defined options.
* BaseCommand.run: call cs.logutils.setup_logging.
*Release 20200229*:
Improve subcommand selection logic, replace StackableValues with stackattrs, drop `cmd` from arguments passed to main/cmd_* methods (present in `options`).
*Release 20200210*:
* New BaseCommand.add_usage_to_docstring class method to be called after class setup, to append the usage message to the class docstring.
* BaseCommand.run: remove spurious Pfx(cmd), as logutils does this for us already.
*Release 20190729*:
BaseCommand: support for a USAGE_FORMAT usage message format string and a getopt_error_handler method.
*Release 20190619.1*:
Another niggling docstring formatting fix.
*Release 20190619*:
Minor documentation updates.
*Release 20190617.2*:
Lint.
*Release 20190617.1*:
Initial release with @docmd decorator and alpha quality BaseCommand command line assistance class.
Raw data
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"name": "cs.cmdutils",
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"maintainer_email": null,
"keywords": "python2, python3",
"author": null,
"author_email": "Cameron Simpson <cs@cskk.id.au>",
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"platform": null,
"description": "Convenience functions for working with the Cmd module,\nthe BaseCommand class for constructing command line programmes,\nand other command line related stuff.\n\n*Latest release 20240422*:\n* BaseCommandOptions.popopts: return the dict from BaseCommand.popopts().\n* BaseCommand.apply_preargv: apply the default options supported by self.options.\n* BaseCommandOptions.update(mapping) method, useful for dropping subcommand-specific defaults onto the options ahead of the local popopts() call.\n\n## Class `BaseCommand`\n\nA base class for handling nestable command lines.\n\nThis class provides the basic parse and dispatch mechanisms\nfor command lines.\nTo implement a command line\none instantiates a subclass of `BaseCommand`:\n\n class MyCommand(BaseCommand):\n GETOPT_SPEC = 'ab:c'\n USAGE_FORMAT = r\"\"\"Usage: {cmd} [-a] [-b bvalue] [-c] [--] arguments...\n -a Do it all.\n -b But using bvalue.\n -c The 'c' option!\n \"\"\"\n ...\n\nand provides either a `main` method if the command has no subcommands\nor a suite of `cmd_`*subcommand* methods, one per subcommand.\n\nRunning a command is done by:\n\n MyCommand(argv).run()\n\nModules which implement a command line mode generally look like this:\n\n ... imports etc ...\n def main(argv=None, **run_kw):\n \"\"\" The command line mode.\n \"\"\"\n return MyCommand(argv).run(**run_kw)\n ... other code ...\n class MyCommand(BaseCommand):\n ... other code ...\n if __name__ == '__main__':\n sys.exit(main(sys.argv))\n\nInstances have a `self.options` attribute on which optional\nmodes are set,\navoiding conflict with the attributes of `self`.\n\nSubclasses with no subcommands\ngenerally just implement a `main(argv)` method.\n\nSubclasses with subcommands\nshould implement a `cmd_`*subcommand*`(argv)` instance method\nfor each subcommand.\nIf a subcommand is itself implemented using `BaseCommand`\nthen it can be a simple attribute:\n\n cmd_subthing = SubThingCommand\n\nReturning to methods, if there is a paragraph in the method docstring\ncommencing with `Usage:`\nthen that paragraph is incorporated automatically\ninto the main usage message.\nExample:\n\n def cmd_ls(self, argv):\n \"\"\" Usage: {cmd} [paths...]\n Emit a listing for the named paths.\n\n Further docstring non-usage information here.\n \"\"\"\n ... do the \"ls\" subcommand ...\n\nThe subclass is customised by overriding the following methods:\n* `apply_opt(opt,val)`:\n apply an individual getopt global command line option\n to `self.options`.\n* `apply_opts(opts)`:\n apply the `opts` to `self.options`.\n `opts` is an `(option,value)` sequence\n as returned by `getopot.getopt`.\n The default implementation iterates over these and calls `apply_opt`.\n* `cmd_`*subcmd*`(argv)`:\n if the command line options are followed by an argument\n whose value is *subcmd*,\n then the method `cmd_`*subcmd*`(subcmd_argv)`\n will be called where `subcmd_argv` contains the command line arguments\n following *subcmd*.\n* `main(argv)`:\n if there are no command line arguments after the options\n or the first argument does not have a corresponding\n `cmd_`*subcmd* method\n then method `main(argv)`\n will be called where `argv` contains the command line arguments.\n* `run_context()`:\n a context manager to provide setup or teardown actions\n to occur before and after the command implementation respectively,\n such as to open and close a database.\n\nEditorial: why not arparse?\nPrimarily because when incorrectly invoked\nan argparse command line prints the help/usage messgae\nand aborts the whole programme with `SystemExit`.\nBut also, I find the whole argparse `add_argument` thing cumbersome.\n\n*Method `BaseCommand.__init__(self, argv=None, *, cmd=None, options=None, **kw_options)`*:\nInitialise the command line.\nRaises `GetoptError` for unrecognised options.\n\nParameters:\n* `argv`:\n optional command line arguments\n including the main command name if `cmd` is not specified.\n The default is `sys.argv`.\n The contents of `argv` are copied,\n permitting desctructive parsing of `argv`.\n* `cmd`:\n optional keyword specifying the command name for context;\n if this is not specified it is taken from `argv.pop(0)`.\n* `options`:\n an optional keyword providing object for command state and context.\n If not specified a new `self.Options` instance\n is allocated for use as `options`.\n The default `Options` class is `BaseCommandOptions`,\n a dataclass with some prefilled attributes and properties\n to aid use later.\nOther keyword arguments are applied to `self.options`\nas attributes.\n\nThe `cmd` and `argv` parameters have some fiddly semantics for convenience.\nThere are 3 basic ways to initialise:\n* `BaseCommand()`: `argv` comes from `sys.argv`\n and the value for `cmd` is derived from `argv[0]`\n* `BaseCommand(argv)`: `argv` is the complete command line\n including the command name and the value for `cmd` is\n derived from `argv[0]`\n* `BaseCommand(argv, cmd=foo)`: `argv` is the command\n arguments _after_ the command name and `cmd` is set to\n `foo`\n\nThe command line arguments are parsed according to\nthe optional `GETOPT_SPEC` class attribute (default `''`).\nIf `getopt_spec` is not empty\nthen `apply_opts(opts)` is called\nto apply the supplied options to the state\nwhere `opts` is the return from `getopt.getopt(argv,getopt_spec)`.\n\nAfter the option parse,\nif the first command line argument *foo*\nhas a corresponding method `cmd_`*foo*\nthen that argument is removed from the start of `argv`\nand `self.cmd_`*foo*`(argv,options,cmd=`*foo*`)` is called\nand its value returned.\nOtherwise `self.main(argv,options)` is called\nand its value returned.\n\nIf the command implementation requires some setup or teardown\nthen this may be provided by the `run_context`\ncontext manager method,\ncalled with `cmd=`*subcmd* for subcommands\nand with `cmd=None` for `main`.\n\n*`BaseCommand.Options`*\n\n*Method `BaseCommand.__init_subclass__()`*:\nUpdate subclasses of `BaseCommand`.\n\nAppends the usage message to the class docstring.\n\n*Method `BaseCommand.apply_opt(self, opt, val)`*:\nHandle an individual global command line option.\n\nThis default implementation raises a `RuntimeError`.\nIt only fires if `getopt` actually gathered arguments\nand would imply that a `GETOPT_SPEC` was supplied\nwithout an `apply_opt` or `apply_opts` method to implement the options.\n\n*Method `BaseCommand.apply_opts(self, opts)`*:\nApply command line options.\n\nSubclasses can override this\nbut it is usually easier to override `apply_opt(opt,val)`.\n\n*Method `BaseCommand.apply_preargv(self, argv)`*:\nDo any preparsing of `argv` before the subcommand/main-args.\nReturn the remaining arguments.\n\nThis default implementation applies the default options\nsupported by `self.options` (an instance of `self.Options`\nclass).\n\n*Method `BaseCommand.cmd_help(argv)`*:\nUsage: {cmd} [-l] [subcommand-names...]\nPrint help for subcommands.\nThis outputs the full help for the named subcommands,\nor the short help for all subcommands if no names are specified.\n-l Long help even if no subcommand-names provided.\n\n*Method `BaseCommand.cmd_shell(self, argv)`*:\nUsage: {cmd}\nRun a command prompt via cmd.Cmd using this command's subcommands.\n\n*Method `BaseCommand.cmdloop(intro=None)`*:\nUse `cmd.Cmd` to run a command loop which calls the `cmd_`* methods.\n\n*Method `BaseCommand.getopt_error_handler(cmd, options, e, usage, subcmd=None)`*:\nThe `getopt_error_handler` method\nis used to control the handling of `GetoptError`s raised\nduring the command line parse\nor during the `main` or `cmd_`*subcmd*` calls.\n\nThis default handler issues a warning containing the exception text,\nprints the usage message to standard error,\nand returns `True` to indicate that the error has been handled.\n\nThe handler is called with these parameters:\n* `cmd`: the command name\n* `options`: the `options` object\n* `e`: the `GetoptError` exception\n* `usage`: the command usage or `None` if this was not provided\n* `subcmd`: optional subcommand name;\n if not `None`, is the name of the subcommand which caused the error\n\nIt returns a true value if the exception is considered handled,\nin which case the main `run` method returns 2.\nIt returns a false value if the exception is considered unhandled,\nin which case the main `run` method reraises the `GetoptError`.\n\nTo let the exceptions out unhandled\nthis can be overridden with a method which just returns `False`.\n\nOtherwise,\nthe handler may perform any suitable action\nand return `True` to contain the exception\nor `False` to cause the exception to be reraised.\n\n*Method `BaseCommand.handle_signal(self, sig, frame, *, runstate: Optional[cs.resources.RunState] = <function <lambda> at 0x104df9f30>)`*:\nThe default signal handler, which cancels the default `RunState`.\n\n*Method `BaseCommand.poparg(argv: List[str], *a, unpop_on_error=False)`*:\nPop the leading argument off `argv` and parse it.\nReturn the parsed argument.\nRaises `getopt.GetoptError` on a missing or invalid argument.\n\nThis is expected to be used inside a `main` or `cmd_*`\ncommand handler method or inside `apply_preargv`.\n\nYou can just use:\n\n value = argv.pop(0)\n\nbut this method provides conversion and valuation\nand a richer failure mode.\n\nParameters:\n* `argv`: the argument list, which is modified in place with `argv.pop(0)`\n* the argument list `argv` may be followed by some help text\n and/or an argument parser function.\n* `validate`: an optional function to validate the parsed value;\n this should return a true value if valid,\n or return a false value or raise a `ValueError` if invalid\n* `unvalidated_message`: an optional message after `validate`\n for values failing the validation\n* `unpop_on_error`: optional keyword parameter, default `False`;\n if true then push the argument back onto the front of `argv`\n if it fails to parse; `GetoptError` is still raised\n\nTypical use inside a `main` or `cmd_*` method might look like:\n\n self.options.word = self.poparg(argv, int, \"a count value\")\n self.options.word = self.poparg(\n argv, int, \"a count value\",\n lambda count: count > 0, \"count should be positive\")\n\nBecause it raises `GetoptError` on a bad argument\nthe normal usage message failure mode follows automatically.\n\nDemonstration:\n\n >>> argv = ['word', '3', 'nine', '4']\n >>> BaseCommand.poparg(argv, \"word to process\")\n 'word'\n >>> BaseCommand.poparg(argv, int, \"count value\")\n 3\n >>> BaseCommand.poparg(argv, float, \"length\")\n Traceback (most recent call last):\n ...\n getopt.GetoptError: length 'nine': float('nine'): could not convert string to float: 'nine'\n >>> BaseCommand.poparg(argv, float, \"width\", lambda width: width > 5)\n Traceback (most recent call last):\n ...\n getopt.GetoptError: width '4': invalid value\n >>> BaseCommand.poparg(argv, float, \"length\")\n Traceback (most recent call last):\n ...\n getopt.GetoptError: length: missing argument\n >>> argv = ['-5', 'zz']\n >>> BaseCommand.poparg(argv, float, \"size\", lambda f: f>0, \"size should be >0\")\n Traceback (most recent call last):\n ...\n getopt.GetoptError: size '-5': size should be >0\n >>> argv # -5 was still consumed\n ['zz']\n >>> BaseCommand.poparg(argv, float, \"size2\", unpop_on_error=True)\n Traceback (most recent call last):\n ...\n getopt.GetoptError: size2 'zz': float('zz'): could not convert string to float: 'zz'\n >>> argv # zz was pushed back\n ['zz']\n\n*Method `BaseCommand.popopts(argv, attrfor=None, **opt_specs)`*:\nParse option switches from `argv`, a list of command line strings\nwith leading option switches.\nModify `argv` in place and return a dict mapping switch names to values.\n\nThe optional positional argument `attrfor`\nmay supply an object whose attributes may be set by the options,\nfor example:\n\n def cmd_foo(self, argv):\n self.popopts(argv, self.options, a='all', j_=('jobs', int))\n ... use self.options.jobs etc ...\n\nThe expected options are specified by the keyword parameters\nin `opt_specs`:\n* options not starting with a letter may be preceeded by an underscore\n to allow use in the parameter list, for example `_1='once'`\n for a `-1` option setting the `once` option name\n* a single letter name specifies a short option\n and a multiletter name specifies a long option\n* options requiring an argument have a trailing underscore\n* options not requiring an argument normally imply a value\n of `True`; if their synonym commences with a dash they will\n imply a value of `False`, for example `n='dry_run',y='-dry_run'`\n\nThe `BaseCommandOptions` class provides a `popopts` method\nwhich is a shim for this method with `attrfor=self` i.e.\nthe options object.\nSo common use in a command method usually looks like this:\n\n class SomeCommand(BaseCommand):\n\n def cmd_foo(self, argv):\n options = self.options\n # accept a -j or --jobs options\n options.popopts(argv, jobs=1, j='jobs')\n print(\"jobs =\", options.jobs)\n\nThe `self.options` object is preprovided as an instance of\nthe `self.Options` class, which is `BaseCommandOptions` by\ndefault. This presupplies support for some basic options\nlike `-v` for \"verbose\" and so forth, and a subcommand\nneed not describe these in a call to `self.options.popopts()`.\n\nExample:\n\n >>> import os.path\n >>> from typing import Optional\n >>> @dataclass\n ... class DemoOptions(BaseCommandOptions):\n ... all: bool = False\n ... jobs: int = 1\n ... number: int = 0\n ... once: bool = False\n ... path: Optional[str] = None\n ... trace_exec: bool = False\n ...\n >>> options = DemoOptions()\n >>> argv = ['-1', '-v', '-y', '-j4', '--path=/foo', 'bah', '-x']\n >>> opt_dict = options.popopts(\n ... argv,\n ... _1='once',\n ... a='all',\n ... j_=('jobs',int),\n ... x='-trace_exec',\n ... y='-dry_run',\n ... dry_run=None,\n ... path_=(str, os.path.isabs, 'not an absolute path'),\n ... verbose=None,\n ... )\n >>> opt_dict\n {'once': True, 'verbose': True, 'dry_run': False, 'jobs': 4, 'path': '/foo'}\n >>> options # doctest: +ELLIPSIS\n DemoOptions(cmd=None, dry_run=False, force=False, quiet=False, runstate_signals=(...), verbose=True, all=False, jobs=4, number=0, once=True, path='/foo', trace_exec=False)\n\n*Method `BaseCommand.repl(self, *argv, banner=None, local=None)`*:\nRun an interactive Python prompt with some predefined local names.\nAka REPL (Read Evaluate Print Loop).\n\nParameters:\n* `argv`: any notional command line arguments\n* `banner`: optional banner string\n* `local`: optional local names mapping\n\nThe default `local` mapping is a `dict` containing:\n* `argv`: from `argv`\n* `options`: from `self.options`\n* `self`: from `self`\n* the attributes of `options`\n* the attributes of `self`\n\nThis is not presented automatically as a subcommand, but\ncommands wishing such a command should provide something\nlike this:\n\n def cmd_repl(self, argv):\n \"\"\" Usage: {cmd}\n Run an interactive Python prompt with some predefined local names.\n \"\"\"\n return self.repl(*argv)\n\n*Method `BaseCommand.run(self, **kw_options)`*:\nRun a command.\nReturns the exit status of the command.\nMay raise `GetoptError` from subcommands.\n\nAny keyword arguments are used to override `self.options` attributes\nfor the duration of the run,\nfor example to presupply a shared `Upd` from an outer context.\n\nIf the first command line argument *foo*\nhas a corresponding method `cmd_`*foo*\nthen that argument is removed from the start of `argv`\nand `self.cmd_`*foo*`(cmd=`*foo*`)` is called\nand its value returned.\nOtherwise `self.main(argv)` is called\nand its value returned.\n\nIf the command implementation requires some setup or teardown\nthen this may be provided by the `run_context()`\ncontext manager method.\n\n*Method `BaseCommand.run_context(*a, upd: Optional[cs.upd.Upd] = <function uses_upd.<locals>.<lambda> at 0x104cea3b0>, **kw)`*:\nThe context manager which surrounds `main` or `cmd_`*subcmd*.\n\nThis default does several things, and subclasses should\noverride it like this:\n\n @contextmanager\n def run_context(self):\n with super().run_context():\n try:\n ... subclass context setup ...\n yield\n finally:\n ... any unconditional cleanup ...\n\n*Method `BaseCommand.subcommand_usage_text(subcmd, usage_format_mapping=None, short=False)`*:\nReturn the usage text for a subcommand.\n\nParameters:\n* `subcmd`: the subcommand name\n* `short`: just include the first line of the usage message,\n intented for when there are many subcommands\n\n*Method `BaseCommand.subcommands()`*:\nReturn a mapping of subcommand names to subcommand specifications\nfor class attributes which commence with `cls.SUBCOMMAND_METHOD_PREFIX`\nby default `'cmd_'`.\n\n*Method `BaseCommand.usage_text(*, cmd=None, format_mapping=None, subcmd=None, short=False)`*:\nCompute the \"Usage:\" message for this class\nfrom the top level `USAGE_FORMAT`\nand the `'Usage:'`-containing docstrings of its `cmd_*` methods.\n\nParameters:\n* `cmd`: optional command name, default derived from the class name\n* `format_mapping`: an optional format mapping for filling\n in format strings in the usage text\n* `subcmd`: constrain the usage to a particular subcommand named `subcmd`;\n this is used to produce a shorter usage for subcommand usage failures\n\n## Class `BaseCommandCmd(cmd.Cmd)`\n\nA `cmd.Cmd` subclass used to provide interactive use of a\ncommand's subcommands.\n\nThe `BaseCommand.cmdloop()` class method instantiates an\ninstance of this cand calls its `.cmdloop()` method\ni.e. `cmd.Cmd.cmdloop`.\n\n## Class `BaseCommandOptions(cs.threads.HasThreadState)`\n\nA base class for the `BaseCommand` `options` object.\n\nThis is the default class for the `self.options` object\navailable during `BaseCommand.run()`,\nand available as the `BaseCommand.Options` attribute.\n\nAny keyword arguments are applied as field updates to the instance.\n\nIt comes prefilled with:\n* `.dry_run=False`\n* `.force=False`\n* `.quiet=False`\n* `.verbose=False`\nand a `.doit` property which is the inverse of `.dry_run`.\n\nIt is recommended that if ``BaseCommand` subclasses use a\ndifferent type for their `Options` that it should be a\nsubclass of `BaseCommandOptions`.\nSince `BaseCommandOptions` is a data class, this typically looks like:\n\n @dataclass\n class Options(BaseCommand.Options):\n ... optional extra fields etc ...\n\n*Method `BaseCommandOptions.__call__(self, **updates)`*:\nCalling the options object returns a context manager whose\nvalue is a shallow copy of the options with any `suboptions` applied.\n\nExample showing the semantics:\n\n >>> from cs.cmdutils import BaseCommandOptions\n >>> @dataclass\n ... class DemoOptions(BaseCommandOptions):\n ... x: int = 0\n ...\n >>> options = DemoOptions(x=1)\n >>> assert options.x == 1\n >>> assert not options.verbose\n >>> with options(verbose=True) as subopts:\n ... assert options is not subopts\n ... assert options.x == 1\n ... assert not options.verbose\n ... assert subopts.x == 1\n ... assert subopts.verbose\n ...\n >>> assert options.x == 1\n >>> assert not options.verbose\n\n*Method `BaseCommandOptions.copy(self, **updates)`*:\nReturn a new instance of `BaseCommandOptions` (well, `type(self)`)\nwhich is a shallow copy of the public attributes from `self.__dict__`.\n\nAny keyword arguments are applied as attribute updates to the copy.\n\n*Property `BaseCommandOptions.doit`*:\nI usually use a `doit` flag,\nthe inverse of `dry_run`.\n\n*`BaseCommandOptions.perthread_state`*\n\n*Method `BaseCommandOptions.popopts(self, argv, **opt_specs)`*:\nConvenience method to appply `BaseCommand.popopts` to the options (`self`).\n\nExample for a `BaseCommand` `cmd_foo` method:\n\n def cmd_foo(self, argv):\n self.options.popopts(\n c_='config',\n l='long',\n x='trace',\n )\n if self.options.dry_run:\n print(\"dry run!\")\n\nThe class attribute `COMMON_OPT_SPECS` is a mapping of\noptions which are always supported. `BaseCommandOptions`\nhas: `COMMON_OPT_SPECS={'n': 'dry_run', 'q': 'quiet', 'v': 'verbose'}`.\n\nA subclass with more common options might extend this like so,\nfrom `cs.hashindex`:\n\n COMMON_OPT_SPECS = dict(\n e='ssh_exe',\n h_='hashname',\n H_='hashindex_exe',\n **BaseCommand.Options.COMMON_OPT_SPECS,\n )\n\n*Method `BaseCommandOptions.update(self, **updates)`*:\nModify the options in place with the mapping `updates`.\nIt would be more normal to call the options in a `with` statement\nas shown for `__call__`.\n\n## Function `docmd(dofunc)`\n\nDecorator for `cmd.Cmd` subclass methods\nto supply some basic quality of service.\n\nThis decorator:\n- wraps the function call in a `cs.pfx.Pfx` for context\n- intercepts `getopt.GetoptError`s, issues a `warning`\n and runs `self.do_help` with the method name,\n then returns `None`\n- intercepts other `Exception`s,\n issues an `exception` log message\n and returns `None`\n\nThe intended use is to decorate `cmd.Cmd` `do_`* methods:\n\n from cmd import Cmd\n from cs.cmdutils import docmd\n ...\n class MyCmd(Cmd):\n @docmd\n def do_something(...):\n ... do something ...\n\n## Function `uses_cmd_options(func, cls=<class 'cs.cmdutils.BaseCommandOptions'>, options_param_name='options')`\n\nA decorator to provide a default parameter containing the\nprevailing `BaseCommandOptions` instance as the `options` keyword\nargument, using the `cs.deco.default_params` decorator factory.\n\nThis allows functions to utilitse global options set by a\ncommand such as `options.dry_run` or `options.verbose` without\nthe tedious plumbing through the entire call stack.\n\nParameters:\n* `cls`: the `BaseCommandOptions` or `BaseCommand` class,\n default `BaseCommandOptions`. If a `BaseCommand` subclass is\n provided its `cls.Options` class is used.\n* `options_param_name`: the parameter name to provide, default `options`\n\nExamples:\n\n @uses_cmd_options\n def f(x,*,options):\n \"\"\" Run directly from the prevailing options. \"\"\"\n if options.verbose:\n print(\"doing f with x =\", x)\n ....\n\n @uses_cmd_options\n def f(x,*,verbose=None,options):\n \"\"\" Get defaults from the prevailing options. \"\"\"\n if verbose is None:\n verbose = options.verbose\n if verbose:\n print(\"doing f with x =\", x)\n ....\n\n# Release Log\n\n\n\n*Release 20240422*:\n* BaseCommandOptions.popopts: return the dict from BaseCommand.popopts().\n* BaseCommand.apply_preargv: apply the default options supported by self.options.\n* BaseCommandOptions.update(mapping) method, useful for dropping subcommand-specific defaults onto the options ahead of the local popopts() call.\n\n*Release 20240412*:\n* BaseCommand.run_context: do not store .upd and .runstate on the options (it confuses options in subcommands and we have @uses_runstate and @uses_upd forthis anyway these days).\n* BaseCommand.run_context: catch SIGQUIT, present the default handler as BaseCommand.handle_signal.\n\n*Release 20240316*:\n* New @uses_cmd_options decorator to provide an \"options\" parameter being the prevailing BaseCommandOptions instance.\n* BaseCommandOptions.popopts: get common options from BaseCommandOptions.COMMON_OPT_SPECS.\n\n*Release 20240211*:\n* Include the first sentence of the subcommand description in the short help.\n* BaseCommandOptions: move the runstate_signals into this directly.\n* BaseCommand: move the run() options stuff into run_context() and have it work on a copy of the original options.\n* BaseCommandCmd: implement get_names(), provide docstrings for the do_* attributes, thus help.\n* BaseCommand.run_context: make runstate and upd keyword only parameters.\n\n*Release 20240201*:\n* BaseCommand.run: catch CancellationError and return 1.\n* BaseCommandCmd.__getattr__: recognise EOF, exit and quit to terminate the cmdloop.\n\n*Release 20231129*:\nBaseCommandOptions: define a runstate field.\n\n*Release 20230703*:\nSmall internal changes.\n\n*Release 20230612*:\n* BaseCommand.cmdloop: fix intro parameter.\n* Other small fixes.\n\n*Release 20230407*:\n* BaseCommand: use @uses_runstate when preparing the command, store as self.options.runstate.\n* Make BaseCommandOptions a data class.\n* Drop any pretence at python 2 support, we're long past that.\n* BaseCommand: new cmdloop method to run a cmd.Cmd instance to run subcommand interactively.\n* BaseCommand: rename shell to repl, add cmd_shell to call cmdloop().\n* Drop BaseCommand.apply_defaults in favour of the Options dataclass.\n* BaseCommand: do setup_logging before initiating the Options instance.\n\n*Release 20230212*:\n* BaseCommand.run_context: update RunState support.\n* BaseCommand.run_context: always be having an self.options.upd.\n\n*Release 20230211*:\nBaseCommand: new shell() method to present an interactive Python prompt for use by subclasses cmd_shell method if desired.\n\n*Release 20221228*:\nMove a lot of the context logic from BaseCommand.run to BaseCommand.run_context, which now must be correctly overridden in subclasses.\n\n*Release 20220918*:\n* BaseCommand.run_context: expand default signals to include SIGHUP, expose as BaseCommand.DEFAULT_SIGNALS.\n* BaseCommand.run: pass in the subclass handle_signal method if present.\n\n*Release 20220626*:\n* BaseCommand.poparg: fix positional argument handling.\n* BaseCommand.poparg: new unpop_on_error=False parameter to support pushing a bad argument back onto the front of the argument list.\n\n*Release 20220606*:\nBaseCommand.run: remove the Upd bodge, too annoying, now fixed in cs.upd I believe.\n\n*Release 20220605*:\n* BaseCommand: new popopts(argv,...) compact getopt wrapper.\n* BaseCommand: new poparg(argv,...) compact validating argument consumer.\n* BaseCommand: drop run_argv, provided no utility.\n* BaseCommand.run: get the RunState signal list from self.options.runstate_signals.\n* BaseCommand.apply_opts: support multiple individual options raising GetoptError, as I hate commands which abort at the first bad option.\n* Assorted other small things.\n\n*Release 20220429*:\n* BaseCommand: fold dots in argv[0] into underscores, supports subcommands like \"setup.py\".\n* BaseCommand: new popargv(argv[,help_text[,parse[,validate[,unvalidated_message]]]]) helper class method.\n* BaseCommand: accept dashed-form of the underscored_form subcommand name.\n* BaseCommand: new self.options.runstate_signals=SIGINT,SIGTERM specifying singals to catch-and-cancel, shuffle run() context managers.\n\n*Release 20220318*:\nBaseCommand.__init__: handle main() method in the New Scheme.\n\n*Release 20220315*:\n_BaseSubCommand.__init__: hook in the class USAGE_KEYWORDS for methods.\n\n*Release 20220311*:\nBaseCommand: big refactor of subcommand internals and make the \"cmd_foo=FooCommand\" implementation work properly.\n\n*Release 20211208*:\nBaseCommand: better handle an unknown subcommand.\n\n*Release 20210927*:\n* Usage: show only the per subcommand usage for in-subcommand GetoptError.\n* Usage: show terse usage when the subcommand cannot be recognised.\n* Usage: support bare -h, -help, --help.\n\n*Release 20210913*:\nNew BaseCommand.apply_preargv method to gather special arguments before subcommands.\n\n*Release 20210906*:\n* BaseCommand.cmd_help: bugfix obsolete parameter list.\n* BaseCommand.SUBCOMMAND_ARGV_DEFAULT: support a single str value, turn into list.\n\n*Release 20210809*:\nBugfix BaseCommand.cmd_help for modern API.\n\n*Release 20210731*:\n* BaseCommand.run: apply optional keyword arguments to self.options during the run.\n* Look for self.SUBCOMMAND_ARGV_DEFAULT if no subcommand is supplied.\n* Bugfix case for \"main\" method and no \"cmd_*\" methods.\n* Bugfix BaseCommand.cmd_help.\n\n*Release 20210420*:\n* BaseCommand.getopt_error_handler: replace error print() with warning().\n* Docstring improvements.\n\n*Release 20210407.1*:\nBaseCommand: bugfix for __init_subclass__ docstring update.\n\n*Release 20210407*:\n* BaseCommand.__init_subclass__: behave sanely if the subclass has no initial __doc__.\n* BaseCommand: new .run_argv convenience method, obviates the \"def main\" boilerplate.\n\n*Release 20210404*:\nBaseCommand subclasses: automatically add the main usage message to the subclass docstring.\n\n*Release 20210306*:\n* BREAKING CHANGE: rework BaseCommand as a more normal class instantiated with argv and with most methods being instance methods, getting the former `options` parameter from self.options.\n* BaseCommand: provide default `apply_opt` and `apply_opts` methods; subclasses will generally just override the former.\n\n*Release 20210123*:\nBaseCommand: propagate the format mapping (cmd, USAGE_KEYWORDS) to the subusage generation.\n\n*Release 20201102*:\n* BaseCommand.cmd_help: supply usage only for \"all commands\", full docstring for specified commands.\n* BaseCommand: honour presupplied options.log_level.\n* BaseCommand.usage_text: handle missing USAGE_FORMAT better.\n* BaseCommand.run: provide options.upd.\n* BaseCommand subclasses may now override BaseCommand.OPTIONS_CLASS (default SimpleNamespace) in order to provide convenience methods on the options.\n* BaseCommand.run: separate variable for subcmd with dash translated to underscore to match method names.\n* Minor fixes.\n\n*Release 20200615*:\nBaseCommand.usage_text: do not mention the \"help\" command if it is the only subcommand (it won't be available if there are no other subcommands).\n\n*Release 20200521.1*:\nFix DISTINFO.install_requires.\n\n*Release 20200521*:\n* BaseCommand.run: support using BaseCommand subclasses as cmd_* names to make it easy to nest BaseCommands.\n* BaseCommand: new hack_postopts_argv method called after parsing the main command line options, for inferring subcommands or the like.\n* BaseCommand: extract \"Usage:\" paragraphs from subcommand method docstrings to build the main usage message.\n* BaseCommand: new cmd_help default command.\n* Assorted bugfixes and small improvements.\n\n*Release 20200318*:\n* BaseCommand.run: make argv optional, get additional usage keywords from self.USAGE_KEYWORDS.\n* @BaseCommand.add_usage_to_docstring: honour cls.USAGE_KEYWORDS.\n* BaseCommand: do not require GETOPT_SPEC for commands with no defined options.\n* BaseCommand.run: call cs.logutils.setup_logging.\n\n*Release 20200229*:\nImprove subcommand selection logic, replace StackableValues with stackattrs, drop `cmd` from arguments passed to main/cmd_* methods (present in `options`).\n\n*Release 20200210*:\n* New BaseCommand.add_usage_to_docstring class method to be called after class setup, to append the usage message to the class docstring.\n* BaseCommand.run: remove spurious Pfx(cmd), as logutils does this for us already.\n\n*Release 20190729*:\nBaseCommand: support for a USAGE_FORMAT usage message format string and a getopt_error_handler method.\n\n*Release 20190619.1*:\nAnother niggling docstring formatting fix.\n\n*Release 20190619*:\nMinor documentation updates.\n\n*Release 20190617.2*:\nLint.\n\n*Release 20190617.1*:\nInitial release with @docmd decorator and alpha quality BaseCommand command line assistance class.\n\n",
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