Source code for airflow.hooks.subprocess

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import os
import signal
from collections import namedtuple
from subprocess import PIPE, STDOUT, Popen
from tempfile import TemporaryDirectory, gettempdir
from typing import Dict, List, Optional

from airflow.hooks.base import BaseHook

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


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

    def __init__(self) -> None:
        self.sub_process = None
        super().__init__()

[docs]    def run_command(
        self, command: List[str], env: Optional[Dict[str, str]] = None, output_encoding: str = 'utf-8'
    ) -> SubprocessResult:
        """
        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.
        :param output_encoding: encoding to use for decoding stdout
        :return: :class:`namedtuple` containing ``exit_code`` and ``output``, the last line from stderr
            or stdout
        """
        self.log.info('Tmp dir root location: \n %s', gettempdir())

        with TemporaryDirectory(prefix='airflowtmp') as tmp_dir:

            def pre_exec():
                # Restore default signal disposition and invoke setsid
                for sig in ('SIGPIPE', 'SIGXFZ', 'SIGXFSZ'):
                    if hasattr(signal, sig):
                        signal.signal(getattr(signal, sig), signal.SIG_DFL)
                os.setsid()

            self.log.info('Running command: %s', command)

            self.sub_process = Popen(
                command,
                stdout=PIPE,
                stderr=STDOUT,
                cwd=tmp_dir,
                env=env if env or env == {} else os.environ,
                preexec_fn=pre_exec,
            )

            self.log.info('Output:')
            line = ''
            for raw_line in iter(self.sub_process.stdout.readline, b''):
                line = raw_line.decode(output_encoding).rstrip()
                self.log.info("%s", line)

            self.sub_process.wait()

            self.log.info('Command exited with return code %s', self.sub_process.returncode)

        return SubprocessResult(exit_code=self.sub_process.returncode, output=line)

[docs]    def send_sigterm(self):
        """Sends 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)