# -*- coding: utf-8 -*-
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from base64 import b64encode
from select import select
from airflow import configuration
from airflow.contrib.hooks.ssh_hook import SSHHook
from airflow.exceptions import AirflowException
from airflow.models import BaseOperator
from airflow.utils.decorators import apply_defaults
[docs]class SSHOperator(BaseOperator):
"""
SSHOperator to execute commands on given remote host using the ssh_hook.
:param ssh_hook: predefined ssh_hook to use for remote execution.
Either `ssh_hook` or `ssh_conn_id` needs to be provided.
:type ssh_hook: airflow.contrib.hooks.ssh_hook.SSHHook
:param ssh_conn_id: connection id from airflow Connections.
`ssh_conn_id` will be ignored if `ssh_hook` is provided.
:type ssh_conn_id: str
:param remote_host: remote host to connect (templated)
Nullable. If provided, it will replace the `remote_host` which was
defined in `ssh_hook` or predefined in the connection of `ssh_conn_id`.
:type remote_host: str
:param command: command to execute on remote host. (templated)
:type command: str
:param timeout: timeout (in seconds) for executing the command.
:type timeout: int
:param do_xcom_push: return the stdout which also get set in xcom by airflow platform
:type do_xcom_push: bool
"""
[docs] template_fields = ('command', 'remote_host')
[docs] template_ext = ('.sh',)
@apply_defaults
def __init__(self,
ssh_hook=None,
ssh_conn_id=None,
remote_host=None,
command=None,
timeout=10,
do_xcom_push=False,
*args,
**kwargs):
super(SSHOperator, self).__init__(*args, **kwargs)
self.ssh_hook = ssh_hook
self.ssh_conn_id = ssh_conn_id
self.remote_host = remote_host
self.command = command
self.timeout = timeout
self.do_xcom_push = do_xcom_push
[docs] def execute(self, context):
try:
if self.ssh_conn_id:
if self.ssh_hook and isinstance(self.ssh_hook, SSHHook):
self.log.info("ssh_conn_id is ignored when ssh_hook is provided.")
else:
self.log.info("ssh_hook is not provided or invalid. " +
"Trying ssh_conn_id to create SSHHook.")
self.ssh_hook = SSHHook(ssh_conn_id=self.ssh_conn_id,
timeout=self.timeout)
if not self.ssh_hook:
raise AirflowException("Cannot operate without ssh_hook or ssh_conn_id.")
if self.remote_host is not None:
self.log.info("remote_host is provided explicitly. " +
"It will replace the remote_host which was defined " +
"in ssh_hook or predefined in connection of ssh_conn_id.")
self.ssh_hook.remote_host = self.remote_host
if not self.command:
raise AirflowException("SSH command not specified. Aborting.")
with self.ssh_hook.get_conn() as ssh_client:
# Auto apply tty when its required in case of sudo
get_pty = False
if self.command.startswith('sudo'):
get_pty = True
# set timeout taken as params
stdin, stdout, stderr = ssh_client.exec_command(command=self.command,
get_pty=get_pty,
timeout=self.timeout
)
# get channels
channel = stdout.channel
# closing stdin
stdin.close()
channel.shutdown_write()
agg_stdout = b''
agg_stderr = b''
# capture any initial output in case channel is closed already
stdout_buffer_length = len(stdout.channel.in_buffer)
if stdout_buffer_length > 0:
agg_stdout += stdout.channel.recv(stdout_buffer_length)
# read from both stdout and stderr
while not channel.closed or \
channel.recv_ready() or \
channel.recv_stderr_ready():
readq, _, _ = select([channel], [], [], self.timeout)
for c in readq:
if c.recv_ready():
line = stdout.channel.recv(len(c.in_buffer))
line = line
agg_stdout += line
self.log.info(line.decode('utf-8').strip('\n'))
if c.recv_stderr_ready():
line = stderr.channel.recv_stderr(len(c.in_stderr_buffer))
line = line
agg_stderr += line
self.log.warning(line.decode('utf-8').strip('\n'))
if stdout.channel.exit_status_ready()\
and not stderr.channel.recv_stderr_ready()\
and not stdout.channel.recv_ready():
stdout.channel.shutdown_read()
stdout.channel.close()
break
stdout.close()
stderr.close()
exit_status = stdout.channel.recv_exit_status()
if exit_status == 0:
# returning output if do_xcom_push is set
if self.do_xcom_push:
enable_pickling = configuration.conf.getboolean(
'core', 'enable_xcom_pickling'
)
if enable_pickling:
return agg_stdout
else:
return b64encode(agg_stdout).decode('utf-8')
else:
error_msg = agg_stderr.decode('utf-8')
raise AirflowException("error running cmd: {0}, error: {1}"
.format(self.command, error_msg))
except Exception as e:
raise AirflowException("SSH operator error: {0}".format(str(e)))
return True
[docs] def tunnel(self):
ssh_client = self.ssh_hook.get_conn()
ssh_client.get_transport()