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# to you under the Apache License, Version 2.0 (the
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# with the License. You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
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# KIND, either express or implied. See the License for the
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# under the License.
from __future__ import annotations
import os
import shutil
from functools import cached_property
from pathlib import Path
from typing import TYPE_CHECKING, Any
from azure.core.exceptions import HttpResponseError
from airflow.configuration import conf
from airflow.utils.log.file_task_handler import FileTaskHandler
from airflow.utils.log.logging_mixin import LoggingMixin
if TYPE_CHECKING:
import logging
from airflow.models.taskinstance import TaskInstance
[docs]class WasbTaskHandler(FileTaskHandler, LoggingMixin):
"""
WasbTaskHandler is a python log handler that handles and reads task instance logs.
It extends airflow FileTaskHandler and uploads to and reads from Wasb remote storage.
"""
[docs] trigger_should_wrap = True
def __init__(
self,
base_log_folder: str,
wasb_log_folder: str,
wasb_container: str,
*,
filename_template: str | None = None,
**kwargs,
) -> None:
super().__init__(base_log_folder, filename_template)
self.handler: logging.FileHandler | None = None
self.wasb_container = wasb_container
self.remote_base = wasb_log_folder
self.log_relative_path = ""
self.closed = False
self.upload_on_close = True
self.delete_local_copy = kwargs.get(
"delete_local_copy", conf.getboolean("logging", "delete_local_logs")
)
@cached_property
[docs] def hook(self):
"""Return WasbHook."""
remote_conn_id = conf.get("logging", "REMOTE_LOG_CONN_ID")
try:
from airflow.providers.microsoft.azure.hooks.wasb import WasbHook
return WasbHook(remote_conn_id)
except Exception:
self.log.exception(
"Could not create a WasbHook with connection id '%s'. "
"Do you have apache-airflow[azure] installed? "
"Does connection the connection exist, and is it "
"configured properly?",
remote_conn_id,
)
return None
[docs] def set_context(self, ti: TaskInstance, *, identifier: str | None = None) -> None:
# todo: remove-at-min-airflow-version-2.8
# after Airflow 2.8 can always pass `identifier`
if getattr(super(), "supports_task_context_logging", False):
super().set_context(ti, identifier=identifier)
else:
super().set_context(ti)
# Local location and remote location is needed to open and
# upload local log file to Wasb remote storage.
if TYPE_CHECKING:
assert self.handler is not None
full_path = self.handler.baseFilename
self.log_relative_path = Path(full_path).relative_to(self.local_base).as_posix()
is_trigger_log_context = getattr(ti, "is_trigger_log_context", False)
self.upload_on_close = is_trigger_log_context or not getattr(ti, "raw", None)
[docs] def close(self) -> None:
"""Close and upload local log file to remote storage Wasb."""
# 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
super().close()
if not self.upload_on_close:
return
local_loc = os.path.join(self.local_base, self.log_relative_path)
remote_loc = os.path.join(self.remote_base, self.log_relative_path)
if os.path.exists(local_loc):
# read log and remove old logs to get just the latest additions
with open(local_loc) as logfile:
log = logfile.read()
wasb_write = self.wasb_write(log, remote_loc, append=True)
if wasb_write and self.delete_local_copy:
shutil.rmtree(os.path.dirname(local_loc))
# Mark closed so we don't double write if close is called twice
self.closed = True
def _read_remote_logs(self, ti, try_number, metadata=None) -> tuple[list[str], list[str]]:
messages = []
logs = []
worker_log_relative_path = self._render_filename(ti, try_number)
# TODO: fix this - "relative path" i.e currently REMOTE_BASE_LOG_FOLDER should start with "wasb"
# unlike others with shceme in URL itself to identify the correct handler.
# This puts limitations on ways users can name the base_path.
prefix = os.path.join(self.remote_base, worker_log_relative_path)
blob_names = []
try:
blob_names = self.hook.get_blobs_list(container_name=self.wasb_container, prefix=prefix)
except HttpResponseError as e:
messages.append(f"tried listing blobs with prefix={prefix} and container={self.wasb_container}")
messages.append(f"could not list blobs {e}")
self.log.exception("can't list blobs")
if blob_names:
uris = [f"https://{self.wasb_container}.blob.core.windows.net/{b}" for b in blob_names]
messages.extend(["Found remote logs:", *[f" * {x}" for x in sorted(uris)]])
else:
messages.append(f"No logs found in WASB; ti=%s {ti}")
for name in sorted(blob_names):
remote_log = ""
try:
remote_log = self.hook.read_file(self.wasb_container, name)
if remote_log:
logs.append(remote_log)
except Exception as e:
messages.append(
f"Unable to read remote blob '{name}' in container '{self.wasb_container}'\n{e}"
)
self.log.exception("Could not read blob")
return messages, logs
def _read(
self, ti, try_number: int, metadata: dict[str, Any] | None = None
) -> tuple[str, dict[str, bool]]:
"""
Read logs of given task instance and try_number from Wasb remote storage.
If failed, read the log from task instance host machine.
todo: when min airflow version >= 2.6, remove this method
:param ti: task instance object
:param try_number: task instance try_number to read logs from
:param metadata: log metadata,
can be used for steaming log reading and auto-tailing.
"""
if hasattr(super(), "_read_remote_logs"):
# from Airflow 2.6, we don't implement the `_read` method.
# if parent has _read_remote_logs, we're >= 2.6
return super()._read(ti, try_number, metadata)
# below is backcompat, for airflow < 2.6
messages, logs = self._read_remote_logs(ti, try_number, metadata)
if not logs:
return super()._read(ti, try_number, metadata)
return "".join([f"*** {x}\n" for x in messages]) + "\n".join(logs), {"end_of_log": True}
[docs] def wasb_log_exists(self, remote_log_location: str) -> bool:
"""
Check if remote_log_location exists in remote storage.
:param remote_log_location: log's location in remote storage
:return: True if location exists else False
"""
try:
return self.hook.check_for_blob(self.wasb_container, remote_log_location)
except Exception as e:
self.log.debug('Exception when trying to check remote location: "%s"', e)
return False
[docs] def wasb_read(self, remote_log_location: str, return_error: bool = False):
"""
Return the log found at the remote_log_location. Returns '' if no logs are found or there is an error.
:param remote_log_location: the log's location in remote storage
:param return_error: if True, returns a string error message if an
error occurs. Otherwise returns '' when an error occurs.
"""
try:
return self.hook.read_file(self.wasb_container, remote_log_location)
except Exception:
msg = f"Could not read logs from {remote_log_location}"
self.log.exception(msg)
# return error if needed
if return_error:
return msg
return ""
[docs] def wasb_write(self, log: str, remote_log_location: str, append: bool = True) -> bool:
"""
Write the log to the remote_log_location. Fails silently if no hook was created.
:param log: the log to write to the remote_log_location
:param remote_log_location: the log's location in remote storage
:param append: if False, any existing log file is overwritten. If True,
the new log is appended to any existing logs.
"""
if append and self.wasb_log_exists(remote_log_location):
old_log = self.wasb_read(remote_log_location)
log = f"{old_log}\n{log}" if old_log else log
try:
self.hook.load_string(log, self.wasb_container, remote_log_location, overwrite=True)
except Exception:
self.log.exception("Could not write logs to %s", remote_log_location)
return False
return True