title: Airflow: ValueError: Unable to configure handler 'processor' - wasb logger
body: <p>I am trying to configure remote logging with Azure blob.</p>
  
  <pre><code>Airflow version: 1.10.2
  Python: 3.6.5
  Ubuntu: 18.04
  </code></pre>
  
  <p>Following are the step I did:</p>
  
  <ol>
  <li>In $AIRFLOW_HOME/config/log_config.py, I have put REMOTE_BASE_LOG_FOLDER = 'wasb-airflow-logs' (This is a folder inside the container (container name: airflow-logs))</li>
  <li>Empty <strong>init</strong>.py is in $AIRFLOW_HOME/config/</li>
  <li>$AIRFLOW_HOME/config/ is added in $PYTHONPATH</li>
  <li>Renamed DEFAULT_LOGGING_CONFIG to LOGGING CONFIG everywhere in $AIRFLOW_HOME/config/log_config.py</li>
  <li>User defined in Airflow blob connection has read/write access to REMOTE_BASE_LOG_FOLDER</li>
  <li>$AIRFLOW_HOME/airflow.cfg it has remote_logging = True
  logging_config_class = log_config.LOGGING_CONFIG
  remote_log_conn_id = </li>
  </ol>
  
  <p>Following is the error:</p>
  
  <pre><code>Unable to load the config, contains a configuration error.
  Traceback (most recent call last):
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 382, in resolve
      found = getattr(found, frag)
  AttributeError: module 'airflow.utils.log' has no attribute 'wasb_task_handler'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 384, in resolve
      self.importer(used)
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/utils/log/wasb_task_handler.py", line 23, in &lt;module&gt;
      from airflow.contrib.hooks.wasb_hook import WasbHook
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/contrib/hooks/wasb_hook.py", line 22, in &lt;module&gt;
      from airflow.hooks.base_hook import BaseHook
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/hooks/base_hook.py", line 28, in &lt;module&gt;
      from airflow.models import Connection
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/models.py", line 86, in &lt;module&gt;
      from airflow.utils.dag_processing import list_py_file_paths
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/utils/dag_processing.py", line 49, in &lt;module&gt;
      from airflow.settings import logging_class_path
  ImportError: cannot import name 'logging_class_path'
  
  The above exception was the direct cause of the following exception:
  
  Traceback (most recent call last):
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 558, in configure
      handler = self.configure_handler(handlers[name])
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 708, in configure_handler
      klass = self.resolve(cname)
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 391, in resolve
      raise v
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 384, in resolve
      self.importer(used)
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/utils/log/wasb_task_handler.py", line 23, in &lt;module&gt;
      from airflow.contrib.hooks.wasb_hook import WasbHook
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/contrib/hooks/wasb_hook.py", line 22, in &lt;module&gt;
      from airflow.hooks.base_hook import BaseHook
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/hooks/base_hook.py", line 28, in &lt;module&gt;
      from airflow.models import Connection
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/models.py", line 86, in &lt;module&gt;
      from airflow.utils.dag_processing import list_py_file_paths
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/utils/dag_processing.py", line 49, in &lt;module&gt;
      from airflow.settings import logging_class_path
  ValueError: Cannot resolve 'airflow.utils.log.wasb_task_handler.WasbTaskHandler': cannot import name 'logging_class_path'
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/home/gsingh/venv/bin/airflow", line 21, in &lt;module&gt;
      from airflow import configuration
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/__init__.py", line 36, in &lt;module&gt;
      from airflow import settings, configuration as conf
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/settings.py", line 262, in &lt;module&gt;
      logging_class_path = configure_logging()
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/logging_config.py", line 73, in configure_logging
      raise e
    File "/home/gsingh/venv/lib/python3.6/site-packages/airflow/logging_config.py", line 68, in configure_logging
      dictConfig(logging_config)
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 795, in dictConfig
      dictConfigClass(config).configure()
    File "/home/gsingh/anaconda3/lib/python3.6/logging/config.py", line 566, in configure
      '%r: %s' % (name, e))
  ValueError: Unable to configure handler 'processor': Cannot resolve 'airflow.utils.log.wasb_task_handler.WasbTaskHandler': cannot import name 'logging_class_path'
  </code></pre>
  
  <p>I am not sure which configuration I am missing. Has anyone faced the same issue?</p>