knack/knack/cli.py at dev · microsoft/knack · GitHub

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# --------------------------------------------------------------------------------------------

# Licensed under the MIT License. See License.txt in the project root for license information.

# --------------------------------------------------------------------------------------------

import os

import sys

from collections import defaultdict

from .invocation import CommandInvoker

from .completion import CLICompletion

from .output import OutputProducer

from .log import CLILogging, get_logger

from .util import CLIError, is_modern_terminal

from .config import CLIConfig

from .query import CLIQuery

from .events import EVENT_CLI_PRE_EXECUTE, EVENT_CLI_SUCCESSFUL_EXECUTE, EVENT_CLI_POST_EXECUTE

from .parser import CLICommandParser

from .commands import CLICommandsLoader

from .help import CLIHelp

logger = get_logger(__name__)

class CLI(object): # pylint: disable=too-many-instance-attributes

""" The main driver for the CLI """

def __init__(self,

cli_name='cli',

config_dir=None,

config_env_var_prefix=None,

out_file=sys.stdout,

config_cls=CLIConfig,

logging_cls=CLILogging,

invocation_cls=CommandInvoker,

output_cls=OutputProducer,

completion_cls=CLICompletion,

query_cls=CLIQuery,

parser_cls=CLICommandParser,

commands_loader_cls=CLICommandsLoader,

help_cls=CLIHelp):

"""

:param cli_name: The name of the CLI (e.g. the executable name 'az')

:type cli_name: str

:param config_dir: Path to store config files for this CLI

:type config_dir: str

:param config_env_var_prefix: The prefix for configuration environment variables

:type config_env_var_prefix: str

:param out_file: File to write output to

:type out_file: file-like object

:param config_cls: Class to handle configuration

:type config_cls: knack.config.CLIConfig

:param logging_cls: Class to handle logging

:type logging_cls: knack.log.CLILogging

:param invocation_cls: Class to handle command invocations

:type invocation_cls: knack.invocation.CommandInvoker

:param output_cls: Class to handle output processing of commands

:type output_cls: knack.output.OutputProducer

:param completion_cls: Class to handle completions

:type completion_cls: knack.completion.CLICompletion

:param query_cls: Class to handle command queries

:type query_cls: knack.query.CLIQuery

:param parser_cls: Class to handler command parsing

:type parser_cls: knack.parser.CLICommandParser

:param commands_loader_cls: Class to handle loading commands

:type commands_loader_cls: knack.commands.CLICommandsLoader

:param help_cls: Class to handle help

:type help_cls: knack.help.CLIHelp

"""

self.name = cli_name

self.out_file = out_file

self.config_cls = config_cls

self.logging_cls = logging_cls

self.output_cls = output_cls

self.parser_cls = parser_cls

self.help_cls = help_cls

self.commands_loader_cls = commands_loader_cls

self.invocation_cls = invocation_cls

self.invocation = None

self._event_handlers = defaultdict(lambda: [])

# Data that's typically backed to persistent storage

self.config = config_cls(

config_dir=config_dir or os.path.expanduser(os.path.join('~', '.{}'.format(cli_name))),

config_env_var_prefix=config_env_var_prefix or cli_name.upper()

)

# In memory collection of key-value data for this current cli. This persists between invocations.

self.data = defaultdict(lambda: None)

self.completion = completion_cls(cli_ctx=self)

self.logging = logging_cls(self.name, cli_ctx=self)

self.output = self.output_cls(cli_ctx=self)

self.result = None

self.query = query_cls(cli_ctx=self)

# As logging is initialized in `invoke`, call `logger.debug` or `logger.info` here won't work.

self.init_debug_log = []

self.init_info_log = []

self.only_show_errors = self.config.getboolean('core', 'only_show_errors', fallback=False)

self.enable_color = self._should_enable_color()

# Enable VT mode only in Windows legacy terminal

self._should_enable_vt_mode = self.enable_color and sys.platform == 'win32' and not is_modern_terminal()

@staticmethod

def _should_show_version(args):

return args and (args[0] == '--version' or args[0] == '-v')

def get_cli_version(self):

""" Get the CLI Version. Override this to define how to get the CLI version

:return: The CLI version

:rtype: str

"""

return ''

def get_runtime_version(self):

""" Get the runtime information.

:return: Runtime information

:rtype: str

"""

import platform

version_info = '\n\n'

version_info += 'Python ({}) {}'.format(platform.system(), sys.version)

version_info += '\n\n'

version_info += 'Python location \'{}\''.format(sys.executable)

version_info += '\n'

return version_info

def show_version(self):

""" Print version information to the out file. """

version_info = self.get_cli_version()

version_info += self.get_runtime_version()

print(version_info, file=self.out_file)

def register_event(self, event_name, handler):

""" Register a callable that will be called when event is raised.

A handler will only be registered once.

:param event_name: The name of the event (see knack.events for in-built events)

:type event_name: str

:param handler: A callback to handle the event

:type handler: function

"""

self._event_handlers[event_name].append(handler)

def unregister_event(self, event_name, handler):

""" Unregister a callable that will be called when event is raised.

:param event_name: The name of the event (see knack.events for in-built events)

:type event_name: str

:param handler: The callback that was used to register the event

:type handler: function

"""

try:

self._event_handlers[event_name].remove(handler)

except ValueError:

pass

def raise_event(self, event_name, **kwargs):

""" Raise an event. Calls each handler in turn with kwargs

:param event_name: The name of the event to raise

:type event_name: str

:param kwargs: Kwargs to be passed to all event handlers

"""

handlers = list(self._event_handlers[event_name])

logger.debug('Event: %s %s', event_name, handlers)

for func in handlers:

func(self, **kwargs)

def exception_handler(self, ex):

""" The default exception handler """

if isinstance(ex, CLIError):

logger.error(ex)

else:

logger.exception(ex)

return 1

def _print_init_log(self):

"""Print the debug/info log from CLI.__init__"""

if self.init_debug_log:

logger.debug('__init__ debug log:\n%s', '\n'.join(self.init_debug_log))

self.init_debug_log.clear()

if self.init_info_log:

logger.info('__init__ info log:\n%s', '\n'.join(self.init_info_log))

self.init_info_log.clear()

def invoke(self, args, initial_invocation_data=None, out_file=None):

""" Invoke a command.

:param args: The arguments that represent the command

:type args: list, tuple

:param initial_invocation_data: Prime the in memory collection of key-value data for this invocation.

:type initial_invocation_data: dict

:param out_file: The file to send output to. If not used, we use out_file for knack.cli.CLI instance

:type out_file: file-like object

:return: The exit code of the invocation

:rtype: int

"""

from .util import CommandResultItem

if not isinstance(args, (list, tuple)):

raise TypeError('args should be a list or tuple.')

exit_code = 0

try:

out_file = out_file or self.out_file

# Enable VT mode if necessary

if out_file is sys.stdout and self._should_enable_vt_mode:

self.init_debug_log.append("Enable VT mode.")

from ._win_vt import enable_vt_mode

if not enable_vt_mode():

# Disable color if we can't enable it

self.enable_color = False

args = self.completion.get_completion_args() or args

self.logging.configure(args)

logger.debug('Command arguments: %s', args)

self._print_init_log()

self.raise_event(EVENT_CLI_PRE_EXECUTE)

if CLI._should_show_version(args):

self.show_version()

self.result = CommandResultItem(None)

else:

self.invocation = self.invocation_cls(cli_ctx=self,

parser_cls=self.parser_cls,

commands_loader_cls=self.commands_loader_cls,

help_cls=self.help_cls,

initial_data=initial_invocation_data)

cmd_result = self.invocation.execute(args)

self.result = cmd_result

exit_code = self.result.exit_code

output_type = self.invocation.data['output']

if cmd_result and cmd_result.result is not None:

formatter = self.output.get_formatter(output_type)

self.output.out(cmd_result, formatter=formatter, out_file=out_file)

self.raise_event(EVENT_CLI_SUCCESSFUL_EXECUTE, result=cmd_result)

except KeyboardInterrupt as ex:

exit_code = 1

self.result = CommandResultItem(None, error=ex, exit_code=exit_code)

except Exception as ex: # pylint: disable=broad-except

exit_code = self.exception_handler(ex)

self.result = CommandResultItem(None, error=ex, exit_code=exit_code)

except SystemExit as ex:

exit_code = ex.code

self.result = CommandResultItem(None, error=ex, exit_code=exit_code)

raise ex

finally:

self.raise_event(EVENT_CLI_POST_EXECUTE)

return exit_code

def _should_enable_color(self):

# When run in a normal terminal, color is only enabled when all conditions are met:

# 1. [core] no_color config is not set

# 2. stdout is a tty

# - Otherwise, if the downstream command doesn't support color, Knack will fail with

# BrokenPipeError: [Errno 32] Broken pipe, like `az --version | head --lines=1`

# https://github.com/Azure/azure-cli/issues/13413

# 3. stderr is a tty.

# - Otherwise, the output in stderr won't have LEVEL tag

# 4. out_file is stdout

no_color_config = self.config.getboolean('core', 'no_color', fallback=False)

# If color is disabled by config explicitly, never enable color

if no_color_config:

self.init_debug_log.append("Color is disabled by config.")

return False

if sys.stdout.isatty() and sys.stderr.isatty() and self.out_file is sys.stdout:

self.init_debug_log.append("Enable color in terminal.")

return True

if 'PYCHARM_HOSTED' in os.environ and sys.stdout == sys.__stdout__ and sys.stderr == sys.__stderr__:

self.init_debug_log.append("Enable color in PyCharm.")

return True

self.init_debug_log.append("Cannot enable color.")

return False

knack/knack/cli.py at dev · microsoft/knack · GitHub

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