xonsh.procs.specs#

Subprocess specification and related utilities.

class xonsh.procs.specs.SubprocSpec(cmd, cls=<class 'subprocess.Popen'>, stdin=None, stdout=None, stderr=None, universal_newlines=False, close_fds=False, captured=False, env=None)[source]#

A container for specifying how a subprocess command should be executed.

Parameters

cmdlist of str: Command to be run.
clsPopen-like: Class to run the subprocess with.
stdinfile-like: Popen file descriptor or flag for stdin.
stdoutfile-like: Popen file descriptor or flag for stdout.
stderrfile-like: Popen file descriptor or flag for stderr.
universal_newlinesbool: Whether or not to use universal newlines.
close_fdsbool: Whether or not to close the file descriptors when the process exits.
capturedbool or str, optional: The flag for if the subprocess is captured, may be one of: False for $[], ‘stdout’ for $(), ‘hiddenobject’ for ![], or ‘object’ for !().
envdict: Replacement environment to run the subporcess in.

Attributes

argslist of str: Arguments as originally supplied.
aliaslist of str, callable, or None: The alias that was resolved for this command, if any.
binary_locstr or None: Path to binary to execute.
is_proxybool: Whether or not the subprocess is or should be run as a proxy.
backgroundbool: Whether or not the subprocess should be started in the background.
threadablebool: Whether or not the subprocess is able to be run in a background thread, rather than the main thread.
pipeline_indexint or None: The index number of this sepc into the pipeline that is being setup.
last_in_pipelinebool: Whether the subprocess is the last in the execution pipeline.
captured_stdoutfile-like: Handle to captured stdin
captured_stderrfile-like: Handle to captured stderr
stacklist of FrameInfo namedtuples or None: The stack of the call-site of alias, if the alias requires it. None otherwise.

classmethod build(cmd, *, cls=<class 'subprocess.Popen'>, **kwargs)[source]#: Creates an instance of the subprocess command, with any modifications and adjustments based on the actual cmd that was received.

prep_env_subproc(kwargs)[source]#: Prepares the environment to use in the subprocess.

prep_preexec_fn(kwargs, pipeline_group=None)[source]#: Prepares the ‘preexec_fn’ keyword argument

redirect_leading()[source]#: Manage leading redirects such as with ‘< input.txt COMMAND’.

redirect_trailing()[source]#: Manages trailing redirects.

resolve_alias()[source]#: Sets alias in command, if applicable.

resolve_alias_cls()[source]#: Determine which proxy class to run an alias with.

resolve_auto_cd()[source]#: Implements AUTO_CD functionality.

resolve_binary_loc()[source]#: Sets the binary location

resolve_executable_commands()[source]#: Resolve command executables, if applicable.

resolve_stack()[source]#: Computes the stack for a callable alias’s call-site, if needed.

run(*, pipeline_group=None)[source]#: Launches the subprocess and returns the object.

kwnames = ('stdin', 'stdout', 'stderr', 'universal_newlines', 'close_fds')#

property stderr#

property stdin#

property stdout#

xonsh.procs.specs.cmds_to_specs(cmds, captured=False, envs=None)[source]#: Converts a list of cmds to a list of SubprocSpec objects that are ready to be executed.

xonsh.procs.specs.default_signal_pauser(n, f)[source]#: Pauses a signal, as needed.

xonsh.procs.specs.get_script_subproc_command(fname, args)[source]#: Given the name of a script outside the path, returns a list representing an appropriate subprocess command to execute the script or None if the argument is not readable or not a script. Raises PermissionError if the script is not executable.

xonsh.procs.specs.is_app_execution_alias(fname)[source]#: App execution aliases behave strangly on Windows and Python. Here we try to detect if a file is an app execution alias.

xonsh.procs.specs.no_pg_xonsh_preexec_fn()[source]#: Default subprocess preexec function for when there is no existing pipeline group.

xonsh.procs.specs.run_subproc(cmds, captured=False, envs=None)[source]#

Runs a subprocess, in its many forms. This takes a list of ‘commands,’ which may be a list of command line arguments or a string, representing a special connecting character. For example:

$ ls | grep wakka

is represented by the following cmds:

[['ls'], '|', ['grep', 'wakka']]

Lastly, the captured argument affects only the last real command.

xonsh.procs.specs.safe_close(x)[source]#: Safely attempts to close an object.

xonsh.procs.specs.safe_open(fname, mode, buffering=- 1)[source]#: Safely attempts to open a file in for xonsh subprocs.