解决这个问题的一种方法是构建一个与自定义装饰器配对的自定义装饰器click.Group class:
自定义装饰器生成器：
def make_exclude_hook_group(callback):
""" for any command that is not decorated, call the callback """
hook_attr_name = 'hook_' + callback.__name__
class HookGroup(click.Group):
""" group to hook context invoke to see if the callback is needed"""
def invoke(self, ctx):
""" group invoke which hooks context invoke """
invoke = ctx.invoke
def ctx_invoke(*args, **kwargs):
""" monkey patched context invoke """
sub_cmd = ctx.command.commands[ctx.invoked_subcommand]
if not isinstance(sub_cmd, click.Group) and \
getattr(sub_cmd, hook_attr_name, True):
# invoke the callback
callback()
return invoke(*args, **kwargs)
ctx.invoke = ctx_invoke
return super(HookGroup, self).invoke(ctx)
def group(self, *args, **kwargs):
""" new group decorator to make sure sub groups are also hooked """
if 'cls' not in kwargs:
kwargs['cls'] = type(self)
return super(HookGroup, self).group(*args, **kwargs)
def decorator(func=None):
if func is None:
# if called other than as decorator, return group class
return HookGroup
setattr(func, hook_attr_name, False)
return decorator
使用装饰器构建器：
要使用装饰器，我们首先需要构建装饰器，如下所示：
bypass_upgrade_check = make_exclude_hook_group(do_upgrade)
然后我们需要将它用作自定义类click.group() like:
@click.group(cls=bypass_upgrade_check())
...
最后，我们可以将任何命令或子命令装饰到不需要使用回调的组中，例如：
@bypass_upgrade_check
@my_group.command()
def my_click_command_without_upgrade():
...
这是如何运作的？
这是可行的，因为 click 是一个设计良好的 OO 框架。这@click.group()装饰器通常会实例化一个click.Group对象，但允许用cls范围。所以继承是一件比较容易的事情click.Group在我们自己的类中并重写所需的方法。
在本例中，我们构建一个装饰器，在不需要调用回调的任何单击函数上设置属性。然后在我们的自定义组中，我们猴子补丁click.Context.invoke()我们的上下文，如果即将执行的命令尚未被修饰，我们调用回调。
测试代码：
import click
def do_upgrade():
print("Performing upgrade")
bypass_upgrade_check = make_exclude_hook_group(do_upgrade)
@click.group(cls=bypass_upgrade_check())
@click.pass_context
def cli(ctx):
pass
@bypass_upgrade_check
@cli.command()
def top_cmd1():
click.echo('cmd1')
@cli.command()
def top_cmd2():
click.echo('cmd2')
@cli.group()
def sub_cmd_group():
click.echo('sub_cmd_group')
@bypass_upgrade_check
@sub_cmd_group.command()
def sub_cmd1():
click.echo('sub_cmd1')
@sub_cmd_group.command()
def sub_cmd2():
click.echo('sub_cmd2')
if __name__ == "__main__":
commands = (
'top_cmd1',
'top_cmd2',
'sub_cmd_group sub_cmd1',
'sub_cmd_group sub_cmd2',
'--help',
)
import sys, time
time.sleep(1)
print('Click Version: {}'.format(click.__version__))
print('Python Version: {}'.format(sys.version))
for cmd in commands:
try:
time.sleep(0.1)
print('-----------')
print('> ' + cmd)
time.sleep(0.1)
cli(cmd.split())
except BaseException as exc:
if str(exc) != '0' and \
not isinstance(exc, (click.ClickException, SystemExit)):
raise
Results:
Click Version: 6.7
Python Version: 3.6.3 (v3.6.3:2c5fed8, Oct 3 2017, 18:11:49) [MSC v.1900 64 bit (AMD64)]
-----------
> top_cmd1
cmd1
-----------
> top_cmd2
Performing upgrade
cmd2
-----------
> sub_cmd_group sub_cmd1
sub_cmd_group
sub_cmd1
-----------
> sub_cmd_group sub_cmd2
Performing upgrade
sub_cmd_group
sub_cmd2
-----------
> --help
Usage: test.py [OPTIONS] COMMAND [ARGS]...
Options:
--help Show this message and exit.
Commands:
sub_cmd_group
top_cmd1
top_cmd2
