SubprocessCommand - `libvcs._internal.subprocess`#

Invokable subprocess wrapper.

Defer running a subprocess, such as by handing to an executor.

Note

This is an internal API not covered by versioning policy.

Examples

SubprocessCommand: Wraps subprocess.Popen and subprocess.run() in a dataclass().

Before:

>>> import subprocess
>>> subprocess.run(
...    ['echo', 'hi'],
...    capture_output=True, universal_newlines=True
... ).stdout
'hi\n'

With this:

>>> cmd = SubprocessCommand(['echo', 'hi'])
>>> cmd.args
['echo', 'hi']
>>> cmd.run(capture_output=True, universal_newlines=True).stdout
'hi\n'

Tweak params before invocation:

>>> cmd = SubprocessCommand(['echo', 'hi'])
>>> cmd.args[1] = 'hello'
>>> cmd.args
['echo', 'hello']
>>> cmd.run(capture_output=True, universal_newlines=True).stdout
'hello\n'

libvcs._internal.subprocess._CMD#

Command

alias of Union[str, bytes, PathLike[str], PathLike[bytes], Sequence[Union[str, bytes, PathLike[str], PathLike[bytes]]]]

class libvcs._internal.subprocess.SubprocessCommand(args, bufsize=-1, executable=None, stdin=None, stdout=None, stderr=None, preexec_fn=None, close_fds=True, shell=False, cwd=None, env=None, creationflags=0, startupinfo=None, restore_signals=True, start_new_session=False, pass_fds=(), umask=-1, pipesize=-1, user=None, group=None, extra_groups=None, universal_newlines=None, text=None, encoding=None, errors=None)[source]#

Bases: SkipDefaultFieldsReprMixin

Wraps a subprocess request. Inspect, mutate, control before invocation.

Parameters:

args (str | bytes | PathLike[str] | PathLike[bytes] | Sequence[str | bytes | PathLike[str] | PathLike[bytes]]) –
bufsize (int) –
executable (str | bytes | PathLike[str] | PathLike[bytes] | None) –
stdin (None | int | IO[Any]) –
stdout (None | int | IO[Any]) –
stderr (None | int | IO[Any]) –
preexec_fn (Callable[[], Any] | None) –
close_fds (bool) –
shell (bool) –
cwd (str | bytes | PathLike[str] | PathLike[bytes] | None) –
env (Mapping[bytes, str | bytes | PathLike[str] | PathLike[bytes]] | Mapping[str, str | bytes | PathLike[str] | PathLike[bytes]] | None) –
creationflags (int) –
startupinfo (Any | None) –
restore_signals (bool) –
start_new_session (bool) –
pass_fds (Any) –
umask (int) –
pipesize (int) –
user (str | None) –
group (str | None) –
extra_groups (list[str] | None) –
universal_newlines (bool | None) –
text (Literal[True] | None) –
encoding (str | None) –
errors (str | None) –

args#

A string, or a sequence of program arguments.

Type:: _CMD

bufsize#

supplied as the buffering argument to the open() function when creating the stdin/stdout/stderr pipe file objects

Type:: int

executable#

A replacement program to execute.

Type:: Optional[StrOrBytesPath]

stdin#

standard output for executed program

Type:: _FILE

stdout#: standard output for executed program

stderr#: standard output for executed program

close_fds#

Type:: Controls closing or inheriting of file descriptors.

shell#

Type:: If true, the command will be executed through the shell.

cwd#

Type:: Sets the current directory before the child is executed.

env#

Type:: Defines the environment variables for the new process.

text#: If True, decode stdin, stdout and stderr using the given encoding (if set) or the system default otherwise.

universal_newlines#: Alias of text, provided for backwards compatibility.

startupinfo#: Windows only

creationflags#: Windows only

preexec_fn#: (POSIX only) An object to be called in the child process just before the child is executed.

restore_signals#: POSIX only

start_new_session#: POSIX only

group#: POSIX only

extra_groups#: POSIX only

user#: POSIX only

umask#: POSIX only

pass_fds#: POSIX only

encoding#: Text mode encoding to use for file objects stdin, stdout and stderr.

errors#: Text mode error handling to use for file objects stdin, stdout and stderr.

Examples

>>> cmd = SubprocessCommand("ls")
>>> cmd.args
'ls'

With shell=True:

>>> cmd = SubprocessCommand("ls -l", shell=True)
>>> cmd.shell
True
>>> cmd.args
'ls -l'
>>> cmd.check_call()
0

args: Union[str, bytes, PathLike[str], PathLike[bytes], Sequence[Union[str, bytes, PathLike[str], PathLike[bytes]]]]#

bufsize: int = -1#

executable: Union[str, bytes, PathLike[str], PathLike[bytes], None] = None#

stdin: Union[None, int, IO[Any]] = None#

stdout: Union[None, int, IO[Any]] = None#

stderr: Union[None, int, IO[Any]] = None#

preexec_fn: Optional[Callable[[], Any]] = None#

close_fds: bool = True#

shell: bool = False#

cwd: Union[str, bytes, PathLike[str], PathLike[bytes], None] = None#

env: Union[Mapping[bytes, Union[str, bytes, PathLike[str], PathLike[bytes]]], Mapping[str, Union[str, bytes, PathLike[str], PathLike[bytes]]], None] = None#

creationflags: int = 0#

startupinfo: Optional[Any] = None#

restore_signals: bool = True#

start_new_session: bool = False#

pass_fds: Any = ()#

umask: int = -1#

pipesize: int = -1#

user: Optional[str] = None#

group: Optional[str] = None#

extra_groups: Optional[list[str]] = None#

universal_newlines: Optional[bool] = None#

text: Optional[Literal[True]] = None#

encoding: Optional[str] = None#

errors: Optional[str] = None#

Popen(args=None, universal_newlines=None, *, text=None, encoding=None, errors=None, **kwargs)[source]#

Run commands subprocess.Popen, optionally overrides via kwargs.

Parameters:

**kwargs (Any) – Overrides existing attributes for subprocess.Popen
args (str | bytes | PathLike[str] | PathLike[bytes] | Sequence[str | bytes | PathLike[str] | PathLike[bytes]] | None) –
universal_newlines (bool | None) –
text (bool | None) –
encoding (str | None) –
errors (str | None) –
**kwargs –

Return type:

Popen[Any]

Examples

>>> cmd = SubprocessCommand(args=['echo', 'hello'])
>>> proc = cmd.Popen(stdout=subprocess.PIPE)
>>> proc.communicate() 

check_call(**kwargs)[source]#

Run command subprocess.check_call(), optionally overrides via kwargs.

Parameters:: **kwargs (dict, optional) – Overrides existing attributes for subprocess.check_call()
Return type:: int

Examples

>>> cmd = SubprocessCommand(args=['echo', 'hello'])
>>> cmd.check_call(stdout=subprocess.PIPE)
0

check_output(universal_newlines=None, *, input=None, encoding=None, errors=None, text=None, **kwargs)[source]#

Run command subprocess.check_output(), optionally override via kwargs.

Parameters:

input (Union[bytes, str], optional) –
pass string to subprocess’s stdin. Bytes by default, str in text mode.

Text mode is triggered by setting any of text, encoding, errors or universal_newlines.
**kwargs (Any) – Overrides existing attributes for subprocess.check_output()
universal_newlines (bool | None) –
encoding (str | None) –
errors (str | None) –
text (bool | None) –
**kwargs –

Return type:

Union[bytes, str]

Examples

>>> cmd = SubprocessCommand(args=['echo', 'hello'])
>>> proc = cmd.check_output(shell=True)

Examples from subprocess:

>>> import subprocess
>>> cmd = SubprocessCommand(
...     ["/bin/sh", "-c", "ls -l non_existent_file ; exit 0"])
>>> cmd.check_output(stderr=subprocess.STDOUT)
b"ls: ...non_existent_file...: No such file or directory\n"

>>> cmd = SubprocessCommand(["sed", "-e", "s/foo/bar/"])
>>> cmd.check_output(input=b"when in the course of fooman events\n")
b'when in the course of barman events\n'

run(universal_newlines=None, *, capture_output=False, check=False, encoding=None, errors=None, input=None, text=None, timeout=None, **kwargs)[source]#

Run command in subprocess.run(), optionally overrides via kwargs.

Parameters:

input (Union[bytes, str], optional) –
pass string to subprocess’s stdin. Bytes by default, str in text mode.

Text mode is triggered by setting any of text, encoding, errors or universal_newlines.
check (bool) – If True and the exit code was non-zero, it raises a subprocess.CalledProcessError. The CalledProcessError object will have the return code in the returncode attribute, and output & stderr attributes if those streams were captured.
timeout (int) – If given, and the process takes too long, a subprocess.TimeoutExpired
**kwargs (dict, optional) – Overrides existing attributes for subprocess.run()
universal_newlines (bool | None) –
capture_output (bool) –
encoding (str | None) –
errors (str | None) –
text (bool | None) –

Return type:

CompletedProcess[Any]

Examples

>>> import subprocess
>>> cmd = SubprocessCommand(
...     ["/bin/sh", "-c", "ls -l non_existent_file ; exit 0"])
>>> cmd.run()
CompletedProcess(args=['/bin/sh', '-c', 'ls -l non_existent_file ; exit 0'],
                 returncode=0)

>>> import subprocess
>>> cmd = SubprocessCommand(
...     ["/bin/sh", "-c", "ls -l non_existent_file ; exit 0"])
>>> cmd.run(check=True)
CompletedProcess(args=['/bin/sh', '-c', 'ls -l non_existent_file ; exit 0'],
                 returncode=0)

>>> cmd = SubprocessCommand(["sed", "-e", "s/foo/bar/"])
>>> completed = cmd.run(input=b"when in the course of fooman events\n")
>>> completed
CompletedProcess(args=['sed', '-e', 's/foo/bar/'], returncode=0)
>>> completed.stderr

>>> cmd = SubprocessCommand(["sed", "-e", "s/foo/bar/"])
>>> completed = cmd.run(input=b"when in the course of fooman events\n",
...                     capture_output=True)
>>> completed
CompletedProcess(args=['sed', '-e', 's/foo/bar/'], returncode=0,
                stdout=b'when in the course of barman events\n', stderr=b'')
>>> completed.stdout
b'when in the course of barman events\n'
>>> completed.stderr
b''

SubprocessCommand - libvcs._internal.subprocess#

SubprocessCommand - `libvcs._internal.subprocess`#