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cli.py
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cli.py
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# --------------------------------------------------------------------------------------------
# Copyright (c) Microsoft Corporation. All rights reserved.
# 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): # pylint: disable=no-self-use
""" 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): # pylint: disable=no-self-use
""" 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): # pylint: disable=no-self-use
""" 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