add django-prometheus integration

contrib/common/gunicorn/gunicorn.ini

@@ -1,6 +1,7 @@
 """gunicorn WSGI server configuration."""
 
 import os
+from prometheus_client import multiprocess
 
 bind = os.environ.get('GUNICORN_BIND', '0.0.0.0:' + os.environ.get('PORT', '8000'))
 workers = os.environ.get('GUNICORN_WORKERS', 4)
@@ -10,3 +11,8 @@ loglevel = os.environ.get('GUNICORN_LOGLEVEL', 'info')
 user = os.environ.get('GUNICORN_USER', 'root')
 group = os.environ.get('GUNICORN_GROUP', 'root')
 timeout = os.environ.get('GUNICORN_TIMEOUT', 30)
+
+
+# Multiprocess mode: https://prometheus.github.io/client_python/multiprocess/
+def child_exit(server, worker):
+    multiprocess.mark_process_dead(worker.pid)

docker/Dockerfile-prod

@@ -22,6 +22,12 @@ RUN apt-get clean && \
     apt-get -y install apt-transport-https ca-certificates gnupg2 locales curl && \
     rm -rf /var/lib/apt/lists/*
 
+
+# Multiprocess mode: https://prometheus.github.io/client_python/multiprocess/
+ENV PROMETHEUS_MULTIPROC_DIR="/tmp/prometheus-metrics"
+RUN mkdir -p /tmp/prometheus-metrics
+
+
 # set UTF-8 locale
 RUN locale-gen en_US.UTF-8
 ENV LANG en_US.UTF-8

requirements/base.txt

@@ -12,6 +12,7 @@ django-filter==2.0.0
 django-import-export==1.2.0
 django-money==0.12.3
 django-mptt==0.11
+django-prometheus==2.2.0
 django-reversion==3.0.5
 django-rq==2.0
 django-sitetree==1.13.0

src/ralph/settings/base.py

@@ -185,6 +185,11 @@ def get_sentinels(sentinels_string):
     }
 }
 
+TRANSITION_TEMPLATES = (
+    ('transitions/release_asset.html', 'Release asset (Metrum)'),
+    ('transitions/return_asset.html', 'Return asset (Metrum)'),
+)
+
 AUTH_USER_MODEL = 'accounts.RalphUser'
 LOGIN_URL = '/login/'
 
@@ -682,6 +687,7 @@ def get_sentinels(sentinels_string):
 # METRICS
 COLLECT_METRICS = False
 ALLOW_PUSH_GRAPHS_DATA_TO_STATSD = False
+PROMETHEUS_METRICS_ENABLED = False
 STATSD_GRAPHS_PREFIX = 'ralph.graphs'
 
 ENABLE_REQUESTS_AND_QUERIES_METRICS = True
@@ -693,6 +699,11 @@ def get_sentinels(sentinels_string):
 CONVERT_TO_DATACENTER_ASSET_DEFAULT_STATUS_ID = 1
 CONVERT_TO_BACKOFFICE_ASSET_DEFAULT_STATUS_ID = 1
 
+if PROMETHEUS_METRICS_ENABLED:
+    INSTALLED_APPS += (
+        'django_prometheus',
+    )
+
 # Currency choices for django-money
 DEFAULT_CURRENCY_CODE = 'XXX'
 CURRENCY_CHOICES = [

src/ralph/settings/prod.py

@@ -79,6 +79,15 @@
         'ralph.lib.metrics.middlewares.RequestMetricsMiddleware',
     ) + MIDDLEWARE
 
+    if bool_from_env('PROMETHEUS_METRICS_ENABLED'):
+        PROMETHEUS_METRICS_ENABLED = True
+        MIDDLEWARE = (
+            'django_prometheus.middleware.PrometheusBeforeMiddleware',
+        ) + MIDDLEWARE
+        MIDDLEWARE = MIDDLEWARE + (
+            'django_prometheus.middleware.PrometheusAfterMiddleware',
+        )
+
     ALLOW_PUSH_GRAPHS_DATA_TO_STATSD = bool_from_env(
         'ALLOW_PUSH_GRAPHS_DATA_TO_STATSD'
     )

src/ralph/urls/base.py

@@ -1,5 +1,7 @@
 from django.conf import settings
 from django.conf.urls import include, url
+from django.urls import path
+from django_prometheus import exports
 from rest_framework.authtoken import views
 from sitetree.sitetreeapp import SiteTree  # noqa
 
@@ -71,3 +73,12 @@
 
 if getattr(settings, 'ENABLE_HERMES_INTEGRATION', False):
     urlpatterns += url(r'^hermes/', include('pyhermes.apps.django.urls')),
+
+if getattr(settings, 'PROMETHEUS_METRICS_ENABLED', False):
+    urlpatterns += [
+        path(
+            "status/prometheus",
+            exports.ExportToDjangoView,
+            name="status-prometheus",
+        )
+    ]