Source code for airflow.sensors.bash
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from __future__ import annotations
import os
from subprocess import PIPE, STDOUT, Popen
from tempfile import NamedTemporaryFile, TemporaryDirectory, gettempdir
from typing import TYPE_CHECKING, Sequence
from airflow.exceptions import AirflowFailException
from airflow.sensors.base import BaseSensorOperator
if TYPE_CHECKING:
from airflow.utils.context import Context
[docs]class BashSensor(BaseSensorOperator):
"""
Executes a bash command/script.
Return 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.
: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)
:param output_encoding: output encoding of bash command.
:param retry_exit_code: If task exits with this code, treat the sensor
as not-yet-complete and retry the check later according to the
usual retry/timeout settings. Any other non-zero return code will
be treated as an error, and cause the sensor to fail. If set to
``None`` (the default), any non-zero exit code will cause a retry
and the task will never raise an error except on time-out.
.. seealso::
For more information on how to use this sensor,take a look at the guide:
:ref:`howto/operator:BashSensor`
"""
[docs] template_fields: Sequence[str] = ("bash_command", "env")
def __init__(
self, *, bash_command, env=None, output_encoding="utf-8", retry_exit_code: int | None = None, **kwargs
):
super().__init__(**kwargs)
self.bash_command = bash_command
self.env = env
self.output_encoding = output_encoding
self.retry_exit_code = retry_exit_code
[docs] def poke(self, context: Context):
"""Execute the bash command in a temporary directory."""
bash_command = self.bash_command
self.log.info("Tmp dir root location: %s", gettempdir())
with TemporaryDirectory(prefix="airflowtmp") as tmp_dir, 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)
with Popen(
["bash", fname],
stdout=PIPE,
stderr=STDOUT,
close_fds=True,
cwd=tmp_dir,
env=self.env,
preexec_fn=os.setsid,
) as resp:
if resp.stdout:
self.log.info("Output:")
for line in iter(resp.stdout.readline, b""):
self.log.info(line.decode(self.output_encoding).strip())
resp.wait()
self.log.info("Command exited with return code %s", resp.returncode)
# zero code means success, the sensor can go green
if resp.returncode == 0:
return True
# we have a retry exit code, sensor retries if return code matches, otherwise error
elif self.retry_exit_code is not None:
if resp.returncode == self.retry_exit_code:
self.log.info("Return code matches retry code, will retry later")
return False
else:
raise AirflowFailException(f"Command exited with return code {resp.returncode}")
# backwards compatibility: sensor retries no matter the error code
else:
self.log.info("Non-zero return code and no retry code set, will retry later")
return False