move metrics_collector to contrib.prometheus & other minor suggestions

Author: terencehonles

README.rst

@@ -373,7 +373,7 @@ Configuring Prometheus
 
 ``django_rq`` also provides a Prometheus compatible view, which can be enabled
 by installing ``prometheus_client`` or installing the extra "prometheus-metrics"
-(``pip install django-rq[prometheus-metrics]``). The metrics are exposed at
+(``pip install django-rq[prometheus]``). The metrics are exposed at
 ``/django-rq/metrics/`` and the following is an example of the metrics that
 are exported::
 

django_rq/metrics_collector.py renamed to django_rq/contrib/prometheus.py

@@ -1,7 +1,7 @@
 from rq.job import JobStatus
 
-from .queues import filter_connection_params, get_connection, get_queue, get_unique_connection_configs
-from .workers import get_worker_class
+from ..queues import filter_connection_params, get_connection, get_queue, get_unique_connection_configs
+from ..workers import get_worker_class
 
 try:
     from prometheus_client import Summary

django_rq/stats_views.py

@@ -10,7 +10,7 @@
 try:
     import prometheus_client
 
-    from .metrics_collector import RQCollector
+    from .contrib.prometheus import RQCollector
 except ImportError:
     prometheus_client = RQCollector = None  # type: ignore[assignment, misc]
 
@@ -23,7 +23,7 @@ def prometheus_metrics(request):
     global registry
 
     if not RQCollector:  # type: ignore[truthy-function]
-        raise Http404
+        raise Http404('prometheus_client has not been installed; install using extra "django-rq[prometheus]"')
 
     if not registry:
         registry = prometheus_client.CollectorRegistry(auto_describe=True)

django_rq/urls.py

@@ -1,7 +1,7 @@
 from django.urls import re_path
 
 from . import stats_views, views
-from .metrics_collector import RQCollector
+from .contrib.prometheus import RQCollector
 
 metrics_view = [
     re_path(r'^metrics/?$', stats_views.prometheus_metrics, name='rq_metrics'),

setup.py

@@ -19,7 +19,7 @@
     },
     install_requires=['django>=3.2', 'rq>=2', 'redis>=3.5'],
     extras_require={
-        'prometheus-metrics': ['prometheus_client>=0.4.0'],
+        'prometheus': ['prometheus_client>=0.4.0'],
         'Sentry': ['sentry-sdk>=1.0.0'],
         'testing': [],
     },