Source code for airflow.sensors.bash

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import os
from subprocess import PIPE, STDOUT, Popen
from tempfile import NamedTemporaryFile, TemporaryDirectory, gettempdir

from airflow.sensors.base import BaseSensorOperator
from airflow.utils.decorators import apply_defaults


[docs]class BashSensor(BaseSensorOperator):
    """
    Executes a bash command/script and returns True if and only if the
    return code is 0.

    :param bash_command: The command, set of commands or reference to a
        bash script (must be '.sh') to be executed.
    :type bash_command: str

    :param env: If env is not None, it must be a mapping that defines the
        environment variables for the new process; these are used instead
        of inheriting the current process environment, which is the default
        behavior. (templated)
    :type env: dict
    :param output_encoding: output encoding of bash command.
    :type output_encoding: str
    """

[docs]    template_fields = ('bash_command', 'env')

    @apply_defaults
    def __init__(self, *, bash_command, env=None, output_encoding='utf-8', **kwargs):
        super().__init__(**kwargs)
        self.bash_command = bash_command
        self.env = env
        self.output_encoding = output_encoding

[docs]    def poke(self, context):
        """
        Execute the bash command in a temporary directory
        which will be cleaned afterwards
        """
        bash_command = self.bash_command
        self.log.info("Tmp dir root location: \n %s", gettempdir())
        with TemporaryDirectory(prefix='airflowtmp') as tmp_dir:
            with NamedTemporaryFile(dir=tmp_dir, prefix=self.task_id) as f:
                f.write(bytes(bash_command, 'utf_8'))
                f.flush()
                fname = f.name
                script_location = tmp_dir + "/" + fname
                self.log.info("Temporary script location: %s", script_location)
                self.log.info("Running command: %s", bash_command)
                resp = Popen(  # pylint: disable=subprocess-popen-preexec-fn
                    ['bash', fname],
                    stdout=PIPE,
                    stderr=STDOUT,
                    close_fds=True,
                    cwd=tmp_dir,
                    env=self.env,
                    preexec_fn=os.setsid,
                )

                self.log.info("Output:")
                for line in iter(resp.stdout.readline, b''):
                    line = line.decode(self.output_encoding).strip()
                    self.log.info(line)
                resp.wait()
                self.log.info("Command exited with return code %s", resp.returncode)

                return not resp.returncode