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# Copyright (c) 2012 - 2022, Anaconda, Inc., and Bokeh Contributors.
# All rights reserved.
#
# The full license is in the file LICENSE.txt, distributed with this software.
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''' Provides a base class for defining subcommands of the Bokeh command
line application.
'''
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# Boilerplate
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from __future__ import annotations
import logging # isort:skip
log = logging.getLogger(__name__)
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# Imports
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# Standard library imports
from abc import ABCMeta, abstractmethod
from argparse import ArgumentParser, Namespace
from typing import (
TYPE_CHECKING,
Any,
ClassVar,
Literal,
Sequence,
Tuple,
Type,
Union,
)
# Bokeh imports
from ..util.dataclasses import (
NotRequired,
Unspecified,
dataclass,
entries,
)
if TYPE_CHECKING:
from typing_extensions import TypeAlias
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# Globals and constants
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__all__ = (
'Subcommand',
)
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# General API
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# Dev API
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@dataclass
class Argument:
action: NotRequired[Literal["store", "store_const", "store_true", "append", "append_const", "count", "help", "version", "extend"]] = Unspecified
nargs: NotRequired[int | Literal["?", "*", "+", "..."]] = Unspecified
const: NotRequired[Any] = Unspecified
default: NotRequired[Any] = Unspecified
type: NotRequired[Type[Any]] = Unspecified
choices: NotRequired[Sequence[Any]] = Unspecified
required: NotRequired[bool] = Unspecified
help: NotRequired[str] = Unspecified
metavar: NotRequired[str] = Unspecified
Arg: TypeAlias = Tuple[Union[str, Tuple[str, ...]], Argument]
Args: TypeAlias = Tuple[Arg, ...]
[docs]class Subcommand(metaclass=ABCMeta):
''' Abstract base class for subcommands
Subclasses should implement an ``invoke(self, args)`` method that accepts
a set of argparse processed arguments as input.
Subclasses should also define the following class attributes:
* ``name`` a name for this subcommand
* ``help`` a help string for argparse to use for this subcommand
* ``args`` the parameters to pass to ``parser.add_argument``
The format of the ``args`` should be a sequence of tuples of the form:
.. code-block:: python
('argname', Argument(
metavar='ARGNAME',
nargs='+',
))
Example:
A simple subcommand "foo" might look like this:
.. code-block:: python
class Foo(Subcommand):
name = "foo"
help = "performs the Foo action"
args = (
('--yell', Argument(
action='store_true',
help="Make it loud",
)),
)
def invoke(self, args):
if args.yell:
print("FOO!")
else:
print("foo")
Then executing ``bokeh foo --yell`` would print ``FOO!`` at the console.
'''
name: ClassVar[str]
help: ClassVar[str]
args: ClassVar[Args] = ()
[docs] def __init__(self, parser: ArgumentParser) -> None:
''' Initialize the subcommand with its parser
Args:
parser (Parser) : an Argparse ``Parser`` instance to configure
with the args for this subcommand.
This method will automatically add all the arguments described in
``self.args``. Subclasses can perform any additional customizations
on ``self.parser``.
'''
self.parser = parser
for arg in self.args:
flags, spec = arg
if not isinstance(flags, tuple):
flags = (flags,)
if not isinstance(spec, dict):
kwargs = dict(entries(spec))
else:
# NOTE: allow dict for run time backwards compatibility, but don't include in types
kwargs = spec
self.parser.add_argument(*flags, **kwargs)
[docs] @abstractmethod
def invoke(self, args: Namespace) -> bool | None:
''' Takes over main program flow to perform the subcommand.
*This method must be implemented by subclasses.*
subclassed overwritten methods return different types:
bool: Build
None: FileOutput (subclassed by HTML, SVG and JSON. PNG overwrites FileOutput.invoke method), Info, Init, \
Sampledata, Secret, Serve, Static
Args:
args (argparse.Namespace) : command line arguments for the subcommand to parse
Raises:
NotImplementedError
'''
raise NotImplementedError("implement invoke()")
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# Private API
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# Code
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