Source code for airflow.providers.amazon.aws.log.cloudwatch_task_handler
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import watchtower
from cached_property import cached_property
from airflow.configuration import conf
from airflow.utils.log.file_task_handler import FileTaskHandler
from airflow.utils.log.logging_mixin import LoggingMixin
[docs]class CloudwatchTaskHandler(FileTaskHandler, LoggingMixin):
"""
CloudwatchTaskHandler is a python log handler that handles and reads task instance logs.
It extends airflow FileTaskHandler and uploads to and reads from Cloudwatch.
:param base_log_folder: base folder to store logs locally
:type base_log_folder: str
:param log_group_arn: ARN of the Cloudwatch log group for remote log storage
with format ``arn:aws:logs:{region name}:{account id}:log-group:{group name}``
:type log_group_arn: str
:param filename_template: template for file name (local storage) or log stream name (remote)
:type filename_template: str
"""
def __init__(self, base_log_folder: str, log_group_arn: str, filename_template: str):
super().__init__(base_log_folder, filename_template)
split_arn = log_group_arn.split(':')
self.handler = None
self.log_group = split_arn[6]
self.region_name = split_arn[3]
self.closed = False
@cached_property
[docs] def hook(self):
"""Returns AwsLogsHook."""
remote_conn_id = conf.get('logging', 'REMOTE_LOG_CONN_ID')
try:
from airflow.providers.amazon.aws.hooks.logs import AwsLogsHook
return AwsLogsHook(aws_conn_id=remote_conn_id, region_name=self.region_name)
except Exception: # pylint: disable=broad-except
self.log.error(
'Could not create an AwsLogsHook with connection id "%s". '
'Please make sure that airflow[aws] is installed and '
'the Cloudwatch logs connection exists.',
remote_conn_id,
)
[docs] def _render_filename(self, ti, try_number):
# Replace unsupported log group name characters
return super()._render_filename(ti, try_number).replace(':', '_')
[docs] def set_context(self, ti):
super().set_context(ti)
self.handler = watchtower.CloudWatchLogHandler(
log_group=self.log_group,
stream_name=self._render_filename(ti, ti.try_number),
boto3_session=self.hook.get_session(self.region_name),
)
[docs] def close(self):
"""Close the handler responsible for the upload of the local log file to Cloudwatch."""
# When application exit, system shuts down all handlers by
# calling close method. Here we check if logger is already
# closed to prevent uploading the log to remote storage multiple
# times when `logging.shutdown` is called.
if self.closed:
return
if self.handler is not None:
self.handler.close()
# Mark closed so we don't double write if close is called twice
self.closed = True
[docs] def _read(self, task_instance, try_number, metadata=None):
stream_name = self._render_filename(task_instance, try_number)
return (
'*** Reading remote log from Cloudwatch log_group: {} log_stream: {}.\n{}\n'.format(
self.log_group, stream_name, self.get_cloudwatch_logs(stream_name=stream_name)
),
{'end_of_log': True},
)
[docs] def get_cloudwatch_logs(self, stream_name: str) -> str:
"""
Return all logs from the given log stream.
:param stream_name: name of the Cloudwatch log stream to get all logs from
:return: string of all logs from the given log stream
"""
try:
events = list(
self.hook.get_log_events(
log_group=self.log_group, log_stream_name=stream_name, start_from_head=True
)
)
return '\n'.join([event['message'] for event in events])
except Exception: # pylint: disable=broad-except
msg = 'Could not read remote logs from log_group: {} log_stream: {}.'.format(
self.log_group, stream_name
)
self.log.exception(msg)
return msg