[AIRFLOW-3439] Decode logs with 'utf-8'

[RasPavel]

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[XD-DENG]

This code change is not changing anything actually. Please refer to my line comment.

Please correct me if I'm wrong.

[XD-DENG]

The default encoding of .decode() is already "utf-8". Please refer to https://docs.python.org/3/library/stdtypes.html#bytes.decode

So .decode('utf-8') is no difference from .decode().

[mik-laj]

So .decode('utf-8') is no difference from .decode().

I have a different opinion. Airflow support Python 2.7, 3.6=> (Source)

In documentation for Python 2.7, you can read a fragment:

Python’s default encoding is the ‘ascii’ encoding.
(Source)

It is also worth quoting another fragment

str.decode([encoding[, errors]])
Decodes the string using the codec registered for encoding. encoding defaults to the default string encoding.
(Source)

Taking into account the quotations above, the change proposed here changes the behavior of the program.

I hope that the explanations are sufficient and clear.

[RasPavel]

Exactly, I get encoding error with python 2.7, forgot to mention that

[XD-DENG]

I see. Thanks @mik-laj and @RasPavel for the clarification

[feng-tao]

lgtm

[acroos]

This actually introduces a bug when using the json-file log driver. The pull method on APIClient returns a generator, which in this case returns dicts. The result is the following error:

[2020-04-29 11:14:59,010] {taskinstance.py:1145} ERROR - 'dict' object has no attribute 'decode'
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/site-packages/airflow/models/taskinstance.py", line 983, in _run_raw_task
    result = task_copy.execute(context=context)
  File "/usr/local/lib/python3.7/site-packages/airflow/operators/docker_operator.py", line 269, in execute
    output = json.loads(l.decode('utf-8').strip())
AttributeError: 'dict' object has no attribute 'decode'