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# to you under the Apache License, Version 2.0 (the
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#
# http://www.apache.org/licenses/LICENSE-2.0
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from __future__ import annotations
from datetime import date, datetime, timedelta, timezone
from functools import cached_property
from typing import TYPE_CHECKING, Any
import watchtower
from airflow.configuration import conf
from airflow.providers.amazon.aws.hooks.logs import AwsLogsHook
from airflow.providers.amazon.aws.utils import datetime_to_epoch_utc_ms
from airflow.utils.log.file_task_handler import FileTaskHandler
from airflow.utils.log.logging_mixin import LoggingMixin
if TYPE_CHECKING:
from airflow.models import TaskInstance
[docs]def json_serialize_legacy(value: Any) -> str | None:
"""
JSON serializer replicating legacy watchtower behavior.
The legacy `watchtower@2.0.1` json serializer function that serialized
datetime objects as ISO format and all other non-JSON-serializable to `null`.
:param value: the object to serialize
:return: string representation of `value` if it is an instance of datetime or `None` otherwise
"""
if isinstance(value, (date, datetime)):
return value.isoformat()
else:
return None
[docs]def json_serialize(value: Any) -> str | None:
"""
JSON serializer replicating current watchtower behavior.
This provides customers with an accessible import,
`airflow.providers.amazon.aws.log.cloudwatch_task_handler.json_serialize`
:param value: the object to serialize
:return: string representation of `value`
"""
return watchtower._json_serialize_default(value)
[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
: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}``
"""
[docs] trigger_should_wrap = True
def __init__(self, base_log_folder: str, log_group_arn: str, **kwargs):
super().__init__(base_log_folder)
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."""
return AwsLogsHook(
aws_conn_id=conf.get("logging", "REMOTE_LOG_CONN_ID"), region_name=self.region_name
)
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: TaskInstance, *, identifier: str | None = None):
super().set_context(ti)
_json_serialize = conf.getimport("aws", "cloudwatch_task_handler_json_serializer", fallback=None)
self.handler = watchtower.CloudWatchLogHandler(
log_group_name=self.log_group,
log_stream_name=self._render_filename(ti, ti.try_number),
use_queues=not getattr(ti, "is_trigger_log_context", False),
boto3_client=self.hook.get_conn(),
json_serialize_default=_json_serialize or json_serialize_legacy,
)
[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
def _read(self, task_instance, try_number, metadata=None):
stream_name = self._render_filename(task_instance, try_number)
try:
return (
f"*** Reading remote log from Cloudwatch log_group: {self.log_group} "
f"log_stream: {stream_name}.\n"
f"{self.get_cloudwatch_logs(stream_name=stream_name, task_instance=task_instance)}\n",
{"end_of_log": True},
)
except Exception as e:
log = (
f"*** Unable to read remote logs from Cloudwatch (log_group: {self.log_group}, log_stream: "
f"{stream_name})\n*** {e}\n\n"
)
self.log.error(log)
local_log, metadata = super()._read(task_instance, try_number, metadata)
log += local_log
return log, metadata
[docs] def get_cloudwatch_logs(self, stream_name: str, task_instance: TaskInstance) -> str:
"""
Return all logs from the given log stream.
:param stream_name: name of the Cloudwatch log stream to get all logs from
:param task_instance: the task instance to get logs about
:return: string of all logs from the given log stream
"""
# If there is an end_date to the task instance, fetch logs until that date + 30 seconds
# 30 seconds is an arbitrary buffer so that we don't miss any logs that were emitted
end_time = (
None
if task_instance.end_date is None
else datetime_to_epoch_utc_ms(task_instance.end_date + timedelta(seconds=30))
)
events = self.hook.get_log_events(
log_group=self.log_group,
log_stream_name=stream_name,
end_time=end_time,
)
return "\n".join(self._event_to_str(event) for event in events)
def _event_to_str(self, event: dict) -> str:
event_dt = datetime.fromtimestamp(event["timestamp"] / 1000.0, tz=timezone.utc)
formatted_event_dt = event_dt.strftime("%Y-%m-%d %H:%M:%S,%f")[:-3]
message = event["message"]
return f"[{formatted_event_dt}] {message}"