Refactor statsd logging

Removed all existing statsd logging and replaced with:

- statsd decorator. Infers the stat name from the decorated function call. Delegates statsd call to statsd client. Calls incr and timing for each decorated method. This is applied to all tasks and all dao methods that touch the notifications/notification_history tables

- statsd client changed to prefix all stats with "notification.api."

- Relies on https://github.com/alphagov/notifications-utils/pull/61 for request logging. Once integrated we pass the statsd client to the logger, allowing us to statsd all API calls. This passes in the start time and the method to be called (NOT the url) onto the global flask object. We then construct statsd counters and timers in the following way

	notifications.api.POST.notifications.send_notification.200

This should allow us to aggregate to the level of

	- API or ADMIN
	- POST or GET etc
	- modules
	- methods
	- status codes

Finally we count the callbacks received from 3rd parties to mapped status.

tests/app/celery/test_tasks.py

@@ -7,10 +7,10 @@ from mock import ANY
 from sqlalchemy.exc import SQLAlchemyError
 from sqlalchemy.orm.exc import NoResultFound
 
-from app import (encryption, DATETIME_FORMAT, statsd_client)
+from app import (encryption, DATETIME_FORMAT)
 from app.celery import provider_tasks
 from app.celery import tasks
-from app.celery.tasks import s3
+from app.celery.tasks import s3, remove_job
 from app.celery.tasks import (
     send_sms,
     process_job,
@@ -53,10 +53,15 @@ def _notification_json(template, to, personalisation=None, job_id=None, row_numb
     return notification
 
 
+def test_should_have_decorated_tasks_functions():
+    assert process_job.__wrapped__.__name__ == 'process_job'
+    assert remove_job.__wrapped__.__name__ == 'remove_job'
+    assert send_sms.__wrapped__.__name__ == 'send_sms'
+    assert send_email.__wrapped__.__name__ == 'send_email'
+
+
 @freeze_time("2016-01-01 11:09:00.061258")
 def test_should_process_sms_job(sample_job, mocker, mock_celery_remove_job):
-    mocker.patch('app.statsd_client.incr')
-    mocker.patch('app.statsd_client.timing')
     mocker.patch('app.celery.tasks.s3.get_job_from_s3', return_value=load_example_csv('sms'))
     mocker.patch('app.celery.tasks.send_sms.apply_async')
     mocker.patch('app.encryption.encrypt', return_value="something_encrypted")
@@ -81,8 +86,6 @@ def test_should_process_sms_job(sample_job, mocker, mock_celery_remove_job):
     )
     job = jobs_dao.dao_get_job_by_id(sample_job.id)
     assert job.status == 'finished'
-    statsd_client.incr.assert_called_once_with("notifications.tasks.process-job")
-    statsd_client.timing.assert_called_once_with("notifications.tasks.process-job.task-time", ANY)
 
 
 @freeze_time("2016-01-01 11:09:00.061258")
@@ -278,9 +281,6 @@ def test_should_send_template_to_correct_sms_task_and_persist(sample_template_wi
     notification = _notification_json(sample_template_with_placeholders,
                                       to="+447234123123", personalisation={"name": "Jo"})
 
-    mocker.patch('app.statsd_client.incr')
-    mocker.patch('app.statsd_client.timing_with_dates')
-    mocker.patch('app.statsd_client.timing')
     mocker.patch('app.celery.provider_tasks.send_sms_to_provider.apply_async')
 
     notification_id = uuid.uuid4()
@@ -292,15 +292,12 @@ def test_should_send_template_to_correct_sms_task_and_persist(sample_template_wi
         datetime.utcnow().strftime(DATETIME_FORMAT)
     )
 
-    statsd_client.timing.assert_called_once_with("notifications.tasks.send-sms.task-time", ANY)
-
     provider_tasks.send_sms_to_provider.apply_async.assert_called_once_with(
         (sample_template_with_placeholders.service_id,
          notification_id),
         queue="sms"
     )
 
-    statsd_client.incr.assert_called_once_with("notifications.tasks.send-sms")
     persisted_notification = Notification.query.filter_by(id=notification_id).one()
     assert persisted_notification.id == notification_id
     assert persisted_notification.to == '+447234123123'
@@ -436,9 +433,6 @@ def test_should_use_email_template_and_persist(sample_email_template_with_placeh
         "my_email@my_email.com",
         {"name": "Jo"},
         row_number=1)
-    mocker.patch('app.statsd_client.incr')
-    mocker.patch('app.statsd_client.timing_with_dates')
-    mocker.patch('app.statsd_client.timing')
     mocker.patch('app.celery.provider_tasks.send_email_to_provider.apply_async')
 
     notification_id = uuid.uuid4()
@@ -456,8 +450,6 @@ def test_should_use_email_template_and_persist(sample_email_template_with_placeh
             key_type=KEY_TYPE_TEAM
         )
 
-    statsd_client.incr.assert_called_once_with("notifications.tasks.send-email")
-    statsd_client.timing.assert_called_once_with("notifications.tasks.send-email.task-time", ANY)
     persisted_notification = Notification.query.filter_by(id=notification_id).one()
     provider_tasks.send_email_to_provider.apply_async.assert_called_once_with(
         (sample_email_template_with_placeholders.service_id, notification_id), queue='email')