Generate prometheus metrics for flask and add metrics endpoint (#399)

server/pyproject.toml

@@ -24,6 +24,7 @@ urllib3 = "^2.2.1"
 pymongo = "<4.9.0"
 pyjwt = "^2.8.0"
 bcrypt = "^4.2.0"
+prometheus-flask-exporter = "^0.23.1"
 
 [tool.poetry.dev-dependencies]
 pytest = "^8.1.2"

server/src/api/v1.py

@@ -38,9 +38,14 @@
 from . import schemas
 
 
-jobs_metric = Counter("jobs", "Number of jobs", ["queue"])
+jobs_metric = Counter(
+    "jobs", "Number of jobs", ["queue"], namespace="testflinger"
+)
 reservations_metric = Counter(
-    "reservations", "Number of reservations", ["queue"]
+    "reservations",
+    "Number of reservations",
+    ["queue"],
+    namespace="testflinger",
 )
 
 

server/src/application.py

@@ -29,6 +29,7 @@
 from src.api.v1 import v1
 from src.providers import ISODatetimeProvider
 from src.views import views
+from .extensions import metrics
 
 try:
     import sentry_sdk
@@ -63,6 +64,9 @@ def create_flask_app(config=None):
             dsn=sentry_dsn, integrations=[FlaskIntegration()]
         )
 
+    metrics.group_by = "endpoint"
+    metrics.init_app(tf_app)
+
     @tf_app.errorhandler(NotFound)
     def handle_404(exc):
         tf_log.error("[404] Not found: %s", request.url)

server/src/extensions.py

@@ -0,0 +1,7 @@
+"""
+Flask extensions that may be imported by other modules
+"""
+
+from prometheus_flask_exporter import PrometheusMetrics
+
+metrics = PrometheusMetrics.for_app_factory()