Source code for airflow.providers.standard.hooks.subprocess

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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
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#
#   http://www.apache.org/licenses/LICENSE-2.0
#
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from __future__ import annotations

import contextlib
import os
import signal
from collections import namedtuple
from collections.abc import Iterator
from subprocess import PIPE, STDOUT, Popen
from tempfile import TemporaryDirectory, gettempdir

from airflow.providers.common.compat.sdk import BaseHook


[docs]

[docs]

[docs]
SubprocessResult = namedtuple("SubprocessResult", ["exit_code", "output"])





@contextlib.contextmanager

[docs]
def working_directory(cwd: str | None = None) -> Iterator[str]:
    """
    Context manager for handling (temporary) working directory.

    Use the given cwd as working directory, if provided.
    Otherwise, create a temporary directory.
    """
    with contextlib.ExitStack() as stack:
        if cwd is None:
            cwd = stack.enter_context(TemporaryDirectory(prefix="airflowtmp"))
        yield cwd




[docs]
class SubprocessHook(BaseHook):
    """Hook for running processes with the ``subprocess`` module."""

    def __init__(self, **kwargs) -> None:

[docs]
        self.sub_process: Popen[bytes] | None = None

        super().__init__(**kwargs)


[docs]
    def run_command(
        self,
        command: list[str],
        env: dict[str, str] | None = None,
        output_encoding: str = "utf-8",
        cwd: str | None = None,
    ) -> SubprocessResult:
        """
        Execute the command.

        If ``cwd`` is None, execute the command in a temporary directory which will be cleaned afterwards.
        If ``env`` is not supplied, ``os.environ`` is passed

        :param command: the command to run
        :param env: Optional dict containing environment variables to be made available to the shell
            environment in which ``command`` will be executed.  If omitted, ``os.environ`` will be used.
            Note, that in case you have Sentry configured, original variables from the environment
            will also be passed to the subprocess with ``SUBPROCESS_`` prefix. See:
            https://airflow.apache.org/docs/apache-airflow/stable/administration-and-deployment/logging-monitoring/errors.html for details.
        :param output_encoding: encoding to use for decoding stdout
        :param cwd: Working directory to run the command in.
            If None (default), the command is run in a temporary directory.
        :return: :class:`namedtuple` containing ``exit_code`` and ``output``, the last line from stderr
            or stdout
        """
        self.log.info("Tmp dir root location: %s", gettempdir())
        with working_directory(cwd=cwd) as cwd:
            self.log.info("Running command: %s", command)

            self.sub_process = Popen(
                command,
                stdout=PIPE,
                stderr=STDOUT,
                cwd=cwd,
                env=env if env or env == {} else os.environ,
                start_new_session=True,
                restore_signals=True,
            )

            self.log.info("Output:")
            line = ""
            if self.sub_process is None:
                raise RuntimeError("The subprocess should be created here and is None!")
            # Neither `with Popen(...)` nor a `finally` close, because both act on the
            # execution_timeout path, where AirflowTaskTimeout (a BaseException) unwinds through here
            # and on_kill() sends SIGTERM to the child only afterwards: __exit__ would block in
            # wait() so that SIGTERM never arrives, and closing stdout would SIGPIPE a child that
            # writes during its own TERM cleanup, since restore_signals=True leaves SIGPIPE at its
            # default action. Closing on success and on Exception leaves that path as it was.
            try:
                if self.sub_process.stdout is not None:
                    for raw_line in iter(self.sub_process.stdout.readline, b""):
                        line = raw_line.decode(output_encoding, errors="backslashreplace").rstrip()
                        self.log.info("%s", line)

                self.sub_process.wait()
            except Exception:
                self._close_stdout()
                raise
            else:
                self._close_stdout()

            self.log.info("Command exited with return code %s", self.sub_process.returncode)
            return_code: int = self.sub_process.returncode

        return SubprocessResult(exit_code=return_code, output=line)


    def _close_stdout(self) -> None:
        if self.sub_process is not None and self.sub_process.stdout is not None:
            self.sub_process.stdout.close()


[docs]
    def send_sigterm(self):
        """Send SIGTERM signal to ``self.sub_process`` if one exists."""
        self.log.info("Sending SIGTERM signal to process group")
        if self.sub_process and hasattr(self.sub_process, "pid"):
            os.killpg(os.getpgid(self.sub_process.pid), signal.SIGTERM)