Module materialize.spawn
Utilities for spawning processes.
The functions in this module are a convenient high-level interface to the
operations provided by the standard subprocess
module.
Expand source code Browse git
# Copyright Materialize, Inc. All rights reserved.
#
# Use of this software is governed by the Business Source License
# included in the LICENSE file at the root of this repository.
#
# As of the Change Date specified in that file, in accordance with
# the Business Source License, use of this software will be governed
# by the Apache License, Version 2.0.
"""Utilities for spawning processes.
The functions in this module are a convenient high-level interface to the
operations provided by the standard [`subprocess`][subprocess] module.
[subprocess]: https://docs.python.org/3/library/subprocess.html
"""
from pathlib import Path
from typing import Dict, Sequence, Union, Optional, IO, overload
from typing_extensions import Literal
import subprocess
from materialize import ui
CalledProcessError = subprocess.CalledProcessError
def runv(
args: Sequence[Union[Path, str]],
cwd: Optional[Path] = None,
stdin: Union[None, int, IO[bytes]] = None,
stdout: Union[None, int, IO[bytes]] = None,
capture_output: bool = False,
env: Optional[Dict[str, str]] = None,
) -> subprocess.CompletedProcess:
"""Verbosely run a subprocess.
A description of the subprocess will be written to stdout before the
subprocess is executed.
Args:
args: A list of strings or paths describing the program to run and
the arguments to pass to it.
cwd: An optional directory to change into before executing the process.
stdin: An optional IO handle to use as the process's stdin stream.
stdout: An optional IO handle to use as the process's stdout stream.
capture_output: Whether to prevent the process from streaming output
the parent process's stdin/stdout handles. If true, the output
will be captured and made available as the `stdout` and `stderr`
fields on the returned `subprocess.CompletedProcess`. Note that
setting this parameter to true will override the behavior of the
`stdout` parameter.
env: If present, overwrite the environment with this dict
Raises:
OSError: The process cannot be executed, e.g. because the specified
program does not exist.
CalledProcessError: The process exited with a non-zero exit status.
"""
print("$", ui.shell_quote(args))
stderr = None
if capture_output:
stdout = subprocess.PIPE
stderr = subprocess.PIPE
return subprocess.run(
args, cwd=cwd, stdin=stdin, stdout=stdout, stderr=stderr, check=True, env=env
)
@overload
def capture(
args: Sequence[Union[Path, str]],
cwd: Optional[Path] = ...,
stdin: Union[None, int, IO[bytes]] = None,
unicode: Literal[False] = ...,
stderr_too: bool = False,
) -> bytes:
...
@overload
def capture(
args: Sequence[Union[Path, str]],
cwd: Optional[Path] = ...,
stdin: Union[None, int, IO[bytes]] = None,
*,
unicode: Literal[True],
stderr_too: bool = False,
) -> str:
...
def capture(
args: Sequence[Union[Path, str]],
cwd: Optional[Path] = None,
stdin: Union[None, int, IO[bytes]] = None,
unicode: bool = False,
stderr_too: bool = False,
) -> Union[str, bytes]:
"""Capture the output of a subprocess.
Args:
args: A list of strings or paths describing the program to run and
the arguments to pass to it.
cwd: An optional directory to change into before executing the process.
stdin: Optional input stream for the process.
unicode: Whether to return output as a unicode string or as bytes.
stderr_too: Whether to capture stderr in the returned value
Returns:
output: The verbatim output of the process as a string or bytes object,
depending on the value of the `unicode` argument. Note that trailing
whitespace is preserved.
Raises:
OSError: The process cannot be executed, e.g. because the specified
program does not exist.
CalledProcessError: The process exited with a non-zero exit status.
.. tip:: Many programs produce output with a trailing newline.
You may want to call `strip()` on the output to remove any trailing
whitespace.
"""
stderr = subprocess.STDOUT if stderr_too else None
return subprocess.check_output( # type: ignore
args, cwd=cwd, stdin=stdin, universal_newlines=unicode, stderr=stderr
)
Functions
def capture(args: Sequence[Union[pathlib.Path, str]], cwd: Union[pathlib.Path, NoneType] = None, stdin: Union[NoneType, int, IO[bytes]] = None, unicode: bool = False, stderr_too: bool = False) -> Union[str, bytes]
-
Capture the output of a subprocess.
Args
args
- A list of strings or paths describing the program to run and the arguments to pass to it.
cwd
- An optional directory to change into before executing the process.
stdin
- Optional input stream for the process.
unicode
- Whether to return output as a unicode string or as bytes.
stderr_too
- Whether to capture stderr in the returned value
Returns
output
- The verbatim output of the process as a string or bytes object,
depending on the value of the
unicode
argument. Note that trailing whitespace is preserved.
Raises
OSError
- The process cannot be executed, e.g. because the specified program does not exist.
CalledProcessError
- The process exited with a non-zero exit status.
Tip: Many programs produce output with a trailing newline.
You may want to call
strip()
on the output to remove any trailing whitespace.Expand source code Browse git
def capture( args: Sequence[Union[Path, str]], cwd: Optional[Path] = None, stdin: Union[None, int, IO[bytes]] = None, unicode: bool = False, stderr_too: bool = False, ) -> Union[str, bytes]: """Capture the output of a subprocess. Args: args: A list of strings or paths describing the program to run and the arguments to pass to it. cwd: An optional directory to change into before executing the process. stdin: Optional input stream for the process. unicode: Whether to return output as a unicode string or as bytes. stderr_too: Whether to capture stderr in the returned value Returns: output: The verbatim output of the process as a string or bytes object, depending on the value of the `unicode` argument. Note that trailing whitespace is preserved. Raises: OSError: The process cannot be executed, e.g. because the specified program does not exist. CalledProcessError: The process exited with a non-zero exit status. .. tip:: Many programs produce output with a trailing newline. You may want to call `strip()` on the output to remove any trailing whitespace. """ stderr = subprocess.STDOUT if stderr_too else None return subprocess.check_output( # type: ignore args, cwd=cwd, stdin=stdin, universal_newlines=unicode, stderr=stderr )
def runv(args: Sequence[Union[pathlib.Path, str]], cwd: Union[pathlib.Path, NoneType] = None, stdin: Union[NoneType, int, IO[bytes]] = None, stdout: Union[NoneType, int, IO[bytes]] = None, capture_output: bool = False, env: Union[Dict[str, str], NoneType] = None) -> subprocess.CompletedProcess
-
Verbosely run a subprocess.
A description of the subprocess will be written to stdout before the subprocess is executed.
Args
args
- A list of strings or paths describing the program to run and the arguments to pass to it.
cwd
- An optional directory to change into before executing the process.
stdin
- An optional IO handle to use as the process's stdin stream.
stdout
- An optional IO handle to use as the process's stdout stream.
capture_output
- Whether to prevent the process from streaming output
the parent process's stdin/stdout handles. If true, the output
will be captured and made available as the
stdout
andstderr
fields on the returnedsubprocess.CompletedProcess
. Note that setting this parameter to true will override the behavior of thestdout
parameter. env
- If present, overwrite the environment with this dict
Raises
OSError
- The process cannot be executed, e.g. because the specified program does not exist.
CalledProcessError
- The process exited with a non-zero exit status.
Expand source code Browse git
def runv( args: Sequence[Union[Path, str]], cwd: Optional[Path] = None, stdin: Union[None, int, IO[bytes]] = None, stdout: Union[None, int, IO[bytes]] = None, capture_output: bool = False, env: Optional[Dict[str, str]] = None, ) -> subprocess.CompletedProcess: """Verbosely run a subprocess. A description of the subprocess will be written to stdout before the subprocess is executed. Args: args: A list of strings or paths describing the program to run and the arguments to pass to it. cwd: An optional directory to change into before executing the process. stdin: An optional IO handle to use as the process's stdin stream. stdout: An optional IO handle to use as the process's stdout stream. capture_output: Whether to prevent the process from streaming output the parent process's stdin/stdout handles. If true, the output will be captured and made available as the `stdout` and `stderr` fields on the returned `subprocess.CompletedProcess`. Note that setting this parameter to true will override the behavior of the `stdout` parameter. env: If present, overwrite the environment with this dict Raises: OSError: The process cannot be executed, e.g. because the specified program does not exist. CalledProcessError: The process exited with a non-zero exit status. """ print("$", ui.shell_quote(args)) stderr = None if capture_output: stdout = subprocess.PIPE stderr = subprocess.PIPE return subprocess.run( args, cwd=cwd, stdin=stdin, stdout=stdout, stderr=stderr, check=True, env=env )