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 descriptiors 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.