Source code for xonsh.main

# -*- coding: utf-8 -*-
"""The main xonsh script."""
import os
import sys
import enum
import argparse
import builtins
import contextlib
import signal
import traceback

from xonsh import __version__
from xonsh.timings import setup_timings
from xonsh.lazyasd import lazyobject
from xonsh.shell import Shell
from xonsh.pretty import pretty
from xonsh.execer import Execer
from xonsh.proc import HiddenCommandPipeline
from xonsh.jobs import ignore_sigtstp
from xonsh.tools import setup_win_unicode_console, print_color, to_bool_or_int
from xonsh.platform import HAS_PYGMENTS, ON_WINDOWS
from xonsh.codecache import run_script_with_cache, run_code_with_cache
from xonsh.xonfig import print_welcome_screen
from xonsh.lazyimps import pygments, pyghooks
from xonsh.imphooks import install_import_hooks
from xonsh.events import events
from xonsh.environ import xonshrc_context


events.transmogrify('on_post_init', 'LoadEvent')
events.doc('on_post_init', """
on_post_init() -> None

Fired after all initialization is finished and we're ready to do work.

NOTE: This is fired before the wizard is automatically started.
""")

events.transmogrify('on_exit', 'LoadEvent')
events.doc('on_exit', """
on_exit() -> None

Fired after all commands have been executed, before tear-down occurs.

NOTE: All the caveats of the ``atexit`` module also apply to this event.
""")


events.transmogrify('on_pre_cmdloop', 'LoadEvent')
events.doc('on_pre_cmdloop', """
on_pre_cmdloop() -> None

Fired just before the command loop is started, if it is.
""")

events.transmogrify('on_post_cmdloop', 'LoadEvent')
events.doc('on_post_cmdloop', """
on_post_cmdloop() -> None

Fired just after the command loop finishes, if it is.

NOTE: All the caveats of the ``atexit`` module also apply to this event.
""")

events.transmogrify('on_pre_rc', 'LoadEvent')
events.doc('on_pre_rc', """
on_pre_rc() -> None

Fired just before rc files are loaded, if they are.
""")

events.transmogrify('on_post_rc', 'LoadEvent')
events.doc('on_post_rc', """
on_post_rc() -> None

Fired just after rc files are loaded, if they are.
""")


[docs]def get_setproctitle(): """Proxy function for loading process title""" try: from setproctitle import setproctitle as spt except ImportError: return return spt
[docs]def path_argument(s): """Return a path only if the path is actually legal This is very similar to argparse.FileType, except that it doesn't return an open file handle, but rather simply validates the path.""" s = os.path.abspath(os.path.expanduser(s)) if not os.path.isfile(s): msg = '{0!r} must be a valid path to a file'.format(s) raise argparse.ArgumentTypeError(msg) return s
@lazyobject def parser(): p = argparse.ArgumentParser(description='xonsh', add_help=False) p.add_argument('-h', '--help', dest='help', action='store_true', default=False, help='show help and exit') p.add_argument('-V', '--version', dest='version', action='store_true', default=False, help='show version information and exit') p.add_argument('-c', help="Run a single command and exit", dest='command', required=False, default=None) p.add_argument('-i', '--interactive', help='force running in interactive mode', dest='force_interactive', action='store_true', default=False) p.add_argument('-l', '--login', help='run as a login shell', dest='login', action='store_true', default=False) p.add_argument('--config-path', help='DEPRECATED: static configuration files may now be used ' 'in the XONSHRC file list, see the --rc option.', dest='config_path', default=None, type=path_argument) p.add_argument('--rc', help="The xonshrc files to load, these may be either xonsh " "files or JSON-based static configuration files.", dest='rc', nargs='+', type=path_argument, default=None) p.add_argument('--no-rc', help="Do not load the .xonshrc files", dest='norc', action='store_true', default=False) p.add_argument('--no-script-cache', help="Do not cache scripts as they are run", dest='scriptcache', action='store_false', default=True) p.add_argument('--cache-everything', help="Use a cache, even for interactive commands", dest='cacheall', action='store_true', default=False) p.add_argument('-D', dest='defines', help='define an environment variable, in the form of ' '-DNAME=VAL. May be used many times.', metavar='ITEM', action='append', default=None) p.add_argument('--shell-type', help='What kind of shell should be used. ' 'Possible options: readline, prompt_toolkit, random. ' 'Warning! If set this overrides $SHELL_TYPE variable.', dest='shell_type', choices=('readline', 'prompt_toolkit', 'best', 'random'), default=None) p.add_argument('--timings', help='Prints timing information before the prompt is shown. ' 'This is useful while tracking down performance issues ' 'and investigating startup times.', dest='timings', action='store_true', default=None) p.add_argument('file', metavar='script-file', help='If present, execute the script in script-file' ' and exit', nargs='?', default=None) p.add_argument('args', metavar='args', help='Additional arguments to the script specified ' 'by script-file', nargs=argparse.REMAINDER, default=[]) return p def _pprint_displayhook(value): if value is None: return builtins._ = None # Set '_' to None to avoid recursion if isinstance(value, HiddenCommandPipeline): builtins._ = value return env = builtins.__xonsh_env__ if env.get('PRETTY_PRINT_RESULTS'): printed_val = pretty(value) else: printed_val = repr(value) if HAS_PYGMENTS and env.get('COLOR_RESULTS'): tokens = list(pygments.lex(printed_val, lexer=pyghooks.XonshLexer())) print_color(tokens) else: print(printed_val) # black & white case builtins._ = value
[docs]class XonshMode(enum.Enum): single_command = 0 script_from_file = 1 script_from_stdin = 2 interactive = 3
[docs]def start_services(shell_kwargs, args): """Starts up the essential services in the proper order. This returns the environment instance as a convenience. """ install_import_hooks() # create execer, which loads builtins ctx = shell_kwargs.get('ctx', {}) debug = to_bool_or_int(os.getenv('XONSH_DEBUG', '0')) events.on_timingprobe.fire(name='pre_execer_init') execer = Execer(xonsh_ctx=ctx, debug_level=debug, scriptcache=shell_kwargs.get('scriptcache', True), cacheall=shell_kwargs.get('cacheall', False)) events.on_timingprobe.fire(name='post_execer_init') # load rc files login = shell_kwargs.get('login', True) env = builtins.__xonsh_env__ rc = shell_kwargs.get('rc', None) rc = env.get('XONSHRC') if rc is None else rc if args.mode != XonshMode.interactive and not args.force_interactive: # Don't load xonshrc if not interactive shell rc = None events.on_pre_rc.fire() xonshrc_context(rcfiles=rc, execer=execer, ctx=ctx, env=env, login=login) events.on_post_rc.fire() # create shell builtins.__xonsh_shell__ = Shell(execer=execer, **shell_kwargs) ctx['__name__'] = '__main__' return env
[docs]def premain(argv=None): """Setup for main xonsh entry point. Returns parsed arguments.""" if argv is None: argv = sys.argv[1:] setup_timings() setproctitle = get_setproctitle() if setproctitle is not None: setproctitle(' '.join(['xonsh'] + argv)) builtins.__xonsh_ctx__ = {} args = parser.parse_args(argv) if args.help: parser.print_help() parser.exit() if args.version: version = '/'.join(('xonsh', __version__)) print(version) parser.exit() shell_kwargs = {'shell_type': args.shell_type, 'completer': False, 'login': False, 'scriptcache': args.scriptcache, 'cacheall': args.cacheall, 'ctx': builtins.__xonsh_ctx__} if args.login: shell_kwargs['login'] = True if args.norc: shell_kwargs['rc'] = () elif args.rc: shell_kwargs['rc'] = args.rc setattr(sys, 'displayhook', _pprint_displayhook) if args.command is not None: args.mode = XonshMode.single_command shell_kwargs['shell_type'] = 'none' elif args.file is not None: args.mode = XonshMode.script_from_file shell_kwargs['shell_type'] = 'none' elif not sys.stdin.isatty() and not args.force_interactive: args.mode = XonshMode.script_from_stdin shell_kwargs['shell_type'] = 'none' else: args.mode = XonshMode.interactive shell_kwargs['completer'] = True shell_kwargs['login'] = True env = start_services(shell_kwargs, args) env['XONSH_LOGIN'] = shell_kwargs['login'] if args.defines is not None: env.update([x.split('=', 1) for x in args.defines]) env['XONSH_INTERACTIVE'] = args.force_interactive or (args.mode == XonshMode.interactive) if ON_WINDOWS: setup_win_unicode_console(env.get('WIN_UNICODE_CONSOLE', True)) return args
def _failback_to_other_shells(args, err): # only failback for interactive shell; if we cannot tell, treat it # as an interactive one for safe. if hasattr(args, 'mode') and args.mode != XonshMode.interactive: raise err foreign_shell = None shells_file = '/etc/shells' if not os.path.exists(shells_file): # right now, it will always break here on Windows raise err excluded_list = ['xonsh', 'screen'] with open(shells_file) as f: for line in f: line = line.strip() if not line or line.startswith('#'): continue if '/' not in line: continue _, shell = line.rsplit('/', 1) if shell in excluded_list: continue if not os.path.exists(line): continue foreign_shell = line break if foreign_shell: traceback.print_exc() print('Xonsh encountered an issue during launch', file=sys.stderr) print('Failback to {}'.format(foreign_shell), file=sys.stderr) os.execlp(foreign_shell, foreign_shell) else: raise err
[docs]def main(argv=None): args = None try: args = premain(argv) return main_xonsh(args) except Exception as err: _failback_to_other_shells(args, err)
[docs]def main_xonsh(args): """Main entry point for xonsh cli.""" if not ON_WINDOWS: def func_sig_ttin_ttou(n, f): pass signal.signal(signal.SIGTTIN, func_sig_ttin_ttou) signal.signal(signal.SIGTTOU, func_sig_ttin_ttou) events.on_post_init.fire() env = builtins.__xonsh_env__ shell = builtins.__xonsh_shell__ try: if args.mode == XonshMode.interactive: # enter the shell env['XONSH_INTERACTIVE'] = True ignore_sigtstp() if (env['XONSH_INTERACTIVE'] and not env['LOADED_CONFIG'] and not any(os.path.isfile(i) for i in env['XONSHRC'])): print_welcome_screen() events.on_pre_cmdloop.fire() try: shell.shell.cmdloop() finally: events.on_post_cmdloop.fire() elif args.mode == XonshMode.single_command: # run a single command and exit run_code_with_cache(args.command.lstrip(), shell.execer, mode='single') elif args.mode == XonshMode.script_from_file: # run a script contained in a file path = os.path.abspath(os.path.expanduser(args.file)) if os.path.isfile(path): sys.argv = [args.file] + args.args env['ARGS'] = sys.argv[:] # $ARGS is not sys.argv env['XONSH_SOURCE'] = path shell.ctx.update({'__file__': args.file, '__name__': '__main__'}) run_script_with_cache(args.file, shell.execer, glb=shell.ctx, loc=None, mode='exec') else: print('xonsh: {0}: No such file or directory.'.format(args.file)) elif args.mode == XonshMode.script_from_stdin: # run a script given on stdin code = sys.stdin.read() run_code_with_cache(code, shell.execer, glb=shell.ctx, loc=None, mode='exec') finally: events.on_exit.fire() postmain(args)
[docs]def postmain(args=None): """Teardown for main xonsh entry point, accepts parsed arguments.""" if ON_WINDOWS: setup_win_unicode_console(enable=False) if hasattr(builtins, '__xonsh_shell__'): del builtins.__xonsh_shell__
@contextlib.contextmanager
[docs]def main_context(argv=None): """Generator that runs pre- and post-main() functions. This has two iterations. The first yields the shell. The second returns None but cleans up the shell. """ args = premain(argv) yield builtins.__xonsh_shell__ postmain(args)
[docs]def setup(ctx=None, shell_type='none', env=(('RAISE_SUBPROC_ERROR', True),)): """Starts up a new xonsh shell. Calling this in function in another packages __init__.py will allow xonsh to be fully used in the package in headless or headed mode. This function is primarily indended to make starting up xonsh for 3rd party packages easier. Parameters ---------- ctx : dict-like or None, optional The xonsh context to start with. If None, an empty dictionary is provided. shell_type : str, optional The type of shell to start. By default this is 'none', indicating we should start in headless mode. env : dict-like, optional Environment to update the current environment with after the shell has been initialized. """ ctx = {} if ctx is None else ctx # setup xonsh ctx and execer builtins.__xonsh_ctx__ = ctx builtins.__xonsh_execer__ = Execer(xonsh_ctx=ctx) builtins.__xonsh_shell__ = Shell(builtins.__xonsh_execer__, ctx=ctx, shell_type='none') builtins.__xonsh_env__.update(env) install_import_hooks()