Add prometheus client metric for number of inbound text messages

As we gradually move from statsd to prometheus, we change the metric to
be a prometheus metric rather than statsd.

The change worth pointing out is that we have dropped the 'successful'
and 'failed' statuses from the metrics. I don't think it's useful to
have these statuses. It's very rare for an inbound message to fail when
we receive it and when it does, we raise an error and see it in our
logs. We aren't going to be looking at a graph of it as it's a rare
event, not typical behaviour that we want to monitor with a graph.

app/notifications/receive_notifications.py

@@ -3,9 +3,9 @@ from urllib.parse import unquote
 
 import iso8601
 from flask import jsonify, Blueprint, current_app, request, abort
+from gds_metrics.metrics import Counter
 from notifications_utils.recipients import try_validate_and_format_phone_number
 
-from app import statsd_client
 from app.celery import tasks
 from app.config import QueueNames
 from app.dao.services_dao import dao_fetch_service_by_inbound_number
@@ -17,6 +17,13 @@ receive_notifications_blueprint = Blueprint('receive_notifications', __name__)
 register_errors(receive_notifications_blueprint)
 
 
+INBOUND_SMS_COUNTER = Counter(
+    'inbound_sms',
+    'Total number of inbound SMS received',
+    ['provider']
+)
+
+
 @receive_notifications_blueprint.route('/notifications/sms/receive/mmg', methods=['POST'])
 def receive_mmg_sms():
     """
@@ -48,7 +55,7 @@ def receive_mmg_sms():
         # we should still tell MMG that we received it successfully
         return 'RECEIVED', 200
 
-    statsd_client.incr('inbound.mmg.successful')
+    INBOUND_SMS_COUNTER.labels("mmg").inc()
 
     inbound = create_inbound_sms_object(service,
                                         content=format_mmg_message(post_data["Message"]),
@@ -93,7 +100,7 @@ def receive_firetext_sms():
                                         date_received=post_data['time'],
                                         provider_name="firetext")
 
-    statsd_client.incr('inbound.firetext.successful')
+    INBOUND_SMS_COUNTER.labels("firetext").inc()
 
     tasks.send_inbound_sms_to_service.apply_async([str(inbound.id), str(service.id)], queue=QueueNames.NOTIFY)
     current_app.logger.debug(
@@ -155,7 +162,6 @@ def fetch_potential_service(inbound_number, provider_name):
         current_app.logger.error('Inbound number "{}" from {} not associated with a service'.format(
             inbound_number, provider_name
         ))
-        statsd_client.incr('inbound.{}.failed'.format(provider_name))
         return False
 
     if not has_inbound_sms_permissions(service.permissions):

tests/app/notifications/test_receive_notification.py

@@ -1,6 +1,5 @@
 import base64
 from datetime import datetime
-from unittest.mock import call
 
 import pytest
 from flask import json
@@ -54,6 +53,7 @@ def mmg_post(client, data, auth=True, password='testkey'):
 
 def test_receive_notification_returns_received_to_mmg(client, mocker, sample_service_full_permissions):
     mocked = mocker.patch("app.notifications.receive_notifications.tasks.send_inbound_sms_to_service.apply_async")
+    prom_counter_labels_mock = mocker.patch('app.notifications.receive_notifications.INBOUND_SMS_COUNTER.labels')
     data = {
         "ID": "1234",
         "MSISDN": "447700900855",
@@ -69,6 +69,9 @@ def test_receive_notification_returns_received_to_mmg(client, mocker, sample_ser
     result = json.loads(response.get_data(as_text=True))
     assert result['status'] == 'ok'
 
+    prom_counter_labels_mock.assert_called_once_with("mmg")
+    prom_counter_labels_mock.return_value.inc.assert_called_once_with()
+
     inbound_sms_id = InboundSms.query.all()[0].id
     mocked.assert_called_once_with(
         [str(inbound_sms_id), str(sample_service_full_permissions.id)], queue="notify-internal-tasks")
@@ -299,7 +302,7 @@ def test_receive_notification_error_if_not_single_matching_service(client, notif
 
 def test_receive_notification_returns_received_to_firetext(notify_db_session, client, mocker):
     mocked = mocker.patch("app.notifications.receive_notifications.tasks.send_inbound_sms_to_service.apply_async")
-    mock = mocker.patch('app.notifications.receive_notifications.statsd_client.incr')
+    prom_counter_labels_mock = mocker.patch('app.notifications.receive_notifications.INBOUND_SMS_COUNTER.labels')
 
     service = create_service_with_inbound_number(
         service_name='b', inbound_number='07111111111', service_permissions=[EMAIL_TYPE, SMS_TYPE, INBOUND_SMS_TYPE])
@@ -311,7 +314,8 @@ def test_receive_notification_returns_received_to_firetext(notify_db_session, cl
     assert response.status_code == 200
     result = json.loads(response.get_data(as_text=True))
 
-    mock.assert_has_calls([call('inbound.firetext.successful')])
+    prom_counter_labels_mock.assert_called_once_with("firetext")
+    prom_counter_labels_mock.return_value.inc.assert_called_once_with()
 
     assert result['status'] == 'ok'
     inbound_sms_id = InboundSms.query.all()[0].id
@@ -320,7 +324,7 @@ def test_receive_notification_returns_received_to_firetext(notify_db_session, cl
 
 def test_receive_notification_from_firetext_persists_message(notify_db_session, client, mocker):
     mocked = mocker.patch("app.notifications.receive_notifications.tasks.send_inbound_sms_to_service.apply_async")
-    mocker.patch('app.notifications.receive_notifications.statsd_client.incr')
+    mocker.patch('app.notifications.receive_notifications.INBOUND_SMS_COUNTER')
 
     service = create_service_with_inbound_number(
         inbound_number='07111111111',
@@ -347,7 +351,7 @@ def test_receive_notification_from_firetext_persists_message(notify_db_session,
 
 def test_receive_notification_from_firetext_persists_message_with_normalized_phone(notify_db_session, client, mocker):
     mocker.patch("app.notifications.receive_notifications.tasks.send_inbound_sms_to_service.apply_async")
-    mocker.patch('app.notifications.receive_notifications.statsd_client.incr')
+    mocker.patch('app.notifications.receive_notifications.INBOUND_SMS_COUNTER')
 
     create_service_with_inbound_number(
         inbound_number='07111111111', service_name='b', service_permissions=[EMAIL_TYPE, SMS_TYPE, INBOUND_SMS_TYPE])
@@ -367,7 +371,7 @@ def test_receive_notification_from_firetext_persists_message_with_normalized_pho
 
 def test_returns_ok_to_firetext_if_mismatched_sms_sender(notify_db_session, client, mocker):
     mocked = mocker.patch("app.notifications.receive_notifications.tasks.send_inbound_sms_to_service.apply_async")
-    mock = mocker.patch('app.notifications.receive_notifications.statsd_client.incr')
+    mocker.patch('app.notifications.receive_notifications.INBOUND_SMS_COUNTER')
 
     create_service_with_inbound_number(
         inbound_number='07111111199', service_name='b', service_permissions=[EMAIL_TYPE, SMS_TYPE, INBOUND_SMS_TYPE])
@@ -381,7 +385,6 @@ def test_returns_ok_to_firetext_if_mismatched_sms_sender(notify_db_session, clie
 
     assert not InboundSms.query.all()
     assert result['status'] == 'ok'
-    mock.assert_has_calls([call('inbound.firetext.failed')])
     mocked.call_count == 0