[Airflow] The remote logging supports the current log mechanism

[SteNicholas]

FileTaskHandler, a python log handler that handles and reads task instance logs, supports the current log mechanism which uses seq_num and try_number to name the log file. The remote log handler like S3TaskHandler should support the log mechanism.

[aqua7regia]

I saw the log file path has been renamed like "{seq_num}_{try_number}.log" if seq_num in task_instance when the FileTaskHandler initial the log file relative path, and the remote log handler still use the name like "{try_number}.log" to upload or download, that may cause the bug.

file_task_handler.py line 247:

if hasattr(ti, 'seq_num') and ti.seq_num > 0:
    number = '{}_{}'.format(ti.seq_num, ti.try_number)
else:
    number = ti.try_number
relative_path = self._render_filename(ti, number)

s3_task_handler.py line 62:

self.log_relative_path = self._render_filename(ti, ti.try_number)

And GCS and Azure log handlers have the same problem.

[SteNicholas]

@aqua7regia , thanks for your reporter for the remote logging handler. I have assigned to you and thanks for your contribution.