title: airflow task is unable to connect to remote oracle database
body: <p>airflow task is unable to connect to remote oracle database but i am able to connect to the same remote oracle database using the same code from python shell.
  i checked running environment is same for both the shell and airflow.
  i am attaching the log error which i am getting.</p>
  
  <pre><code>[2018-07-18 13:12:11,037] {models.py:1428} INFO - Executing &lt;Task(AadharNumberValidation): validating_data&gt; on 2018-07-18 07:42:05.573491
  [2018-07-18 13:12:11,037] {base_task_runner.py:115} INFO - Running: ['bash', '-c', 'airflow run data_validation validating_data 2018-07-18T07:42:05.573491 --job_id 206 --raw -sd /Users/b0204890/Desktop/python/airflow_home/dags/data_validaton.py']
  [2018-07-18 13:12:11,531] {base_task_runner.py:98} INFO - Subtask: [2018-07-18 13:12:11,531] {__init__.py:45} INFO - Using executor SequentialExecutor
  [2018-07-18 13:12:11,588] {base_task_runner.py:98} INFO - Subtask: [2018-07-18 13:12:11,588] {models.py:189} INFO - Filling up the DagBag from /Users/b0204890/Desktop/python/airflow_home/dags/data_validaton.py
  [2018-07-18 13:12:11,661] {cli.py:374} INFO - Running on host LTB0204890-Mac.local
  [2018-07-18 13:12:11,669] {base_task_runner.py:98} INFO - Subtask: [2018-07-18 13:12:11,669] {validation_operators.py:37} INFO - operator_param yadav: Script one validation
  [2018-07-18 13:12:11,678] {models.py:1595} ERROR - DPI-1047: 64-bit Oracle Client library cannot be loaded: "dlopen(libclntsh.dylib, 1): image not found". See https://oracle.github.io/odpi/doc/installation.html#macos for help
  Traceback (most recent call last):
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/models.py", line 1493, in _run_raw_task
      result = task_copy.execute(context=context)
    File "/Users/b0204890/Desktop/python//airflow_home/plugins/validation_operators.py", line 38, in execute
      cursor = create_connection(user="USERNAME",port="PORT",host="HOST",pwd="password",sid="SID")
    File "/Users/b0204890/Desktop/python/airflow_home/utility/validation.py", line 30, in create_connection
      connection = cx_Oracle.connect(user, pwd, service)
  cx_Oracle.DatabaseError: DPI-1047: 64-bit Oracle Client library cannot be loaded: "dlopen(libclntsh.dylib, 1): image not found". See https://oracle.github.io/odpi/doc/installation.html#macos for help
  [2018-07-18 13:12:11,681] {models.py:1616} INFO - Marking task as UP_FOR_RETRY
  [2018-07-18 13:12:11,682] {base_task_runner.py:98} INFO - Subtask: [2018-07-18 13:12:11,682] {configuration.py:206} WARNING - section/key [smtp/smtp_user] not found in config
  [2018-07-18 13:12:11,684] {models.py:1628} ERROR - Failed to send email to: ['tushar.smartcorp@gmail.com']
  [2018-07-18 13:12:11,684] {models.py:1629} ERROR - [Errno 61] Connection refused
  Traceback (most recent call last):
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/models.py", line 1493, in _run_raw_task
      result = task_copy.execute(context=context)
    File "/Users/b0204890/Desktop/python//airflow_home/plugins/validation_operators.py", line 38, in execute
      cursor = create_connection(user="USERNAME",port="PORT",host="HOST",pwd="PASSWORD",sid="SID")
    File "/Users/b0204890/Desktop/python/airflow_home/utility/validation.py", line 30, in create_connection
      connection = cx_Oracle.connect(user, pwd, service)
  cx_Oracle.DatabaseError: DPI-1047: 64-bit Oracle Client library cannot be loaded: "dlopen(libclntsh.dylib, 1): image not found". See https://oracle.github.io/odpi/doc/installation.html#macos for help
  
  During handling of the above exception, another exception occurred:
  
  Traceback (most recent call last):
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/models.py", line 1618, in handle_failure
      self.email_alert(error, is_retry=True)
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/models.py", line 1779, in email_alert
      send_email(task.email, title, body)
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/utils/email.py", line 44, in send_email
      return backend(to, subject, html_content, files=files, dryrun=dryrun, cc=cc, bcc=bcc, mime_subtype=mime_subtype)
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/utils/email.py", line 87, in send_email_smtp
      send_MIME_email(SMTP_MAIL_FROM, recipients, msg, dryrun)
    File "/Users/b0204890/venv/python3/lib/python3.6/site-packages/airflow/utils/email.py", line 107, in send_MIME_email
      s = smtplib.SMTP_SSL(SMTP_HOST, SMTP_PORT) if SMTP_SSL else smtplib.SMTP(SMTP_HOST, SMTP_PORT)
    File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/smtplib.py", line 251, in __init__
      (code, msg) = self.connect(host, port)
    File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/smtplib.py", line 336, in connect
      self.sock = self._get_socket(host, port, self.timeout)
    File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/smtplib.py", line 307, in _get_socket
      self.source_address)
    File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socket.py", line 724, in create_connection
      raise err
    File "/usr/local/Cellar/python/3.6.5_1/Frameworks/Python.framework/Versions/3.6/lib/python3.6/socket.py", line 713, in create_connection
      sock.connect(sa)
  ConnectionRefusedError: [Errno 61] Connection refused
  </code></pre>