Use our own fork of gds_metrics_python and add shared auth token

This will allow both prometheis (the shared one and our own) to scrape
the /metrics endpoint, each with their own authentication

manifest.yml.j2

@@ -122,6 +122,7 @@ applications:
       ROUTE_SECRET_KEY_1: '{{ ROUTE_SECRET_KEY_1 }}'
       ROUTE_SECRET_KEY_2: '{{ ROUTE_SECRET_KEY_2 }}'
       CRONITOR_KEYS: '{{ CRONITOR_KEYS | tojson }}'
+      METRICS_BASIC_AUTH_TOKEN: {{ METRICS_BASIC_AUTH_TOKEN }}
 
       HIGH_VOLUME_SERVICE: '{{ HIGH_VOLUME_SERVICE | tojson }}'
 

requirements.in

@@ -33,4 +33,4 @@ notifications-utils @ git+https://github.com/alphagov/notifications-utils.git@55
 
 # gds-metrics requires prometheseus 0.2.0, override that requirement as 0.7.1 brings significant performance gains
 prometheus-client==0.14.1
-gds-metrics==0.2.4
+git+https://github.com/alphagov/gds_metrics_python.git@6f1840a57b6fb1ee40b7e84f2f18ec229de8aa72

requirements.txt

@@ -98,14 +98,16 @@ flask-sqlalchemy @ git+https://github.com/mitsuhiko/flask-sqlalchemy.git@500e732
     #   flask-migrate
 fqdn==1.5.1
     # via jsonschema
-gds-metrics==0.2.4
+gds-metrics @ git+https://github.com/alphagov/gds_metrics_python.git@6f1840a57b6fb1ee40b7e84f2f18ec229de8aa72
     # via -r requirements.in
 geojson==2.5.0
     # via notifications-utils
 govuk-bank-holidays==0.10
     # via notifications-utils
 greenlet==1.1.2
-    # via eventlet
+    # via
+    #   eventlet
+    #   sqlalchemy
 gunicorn @ git+https://github.com/benoitc/gunicorn.git@1299ea9e967a61ae2edebe191082fd169b864c64
     # via -r requirements.in
 idna==3.3