Discourse Prometheus

Plugin
,
1
:discourse2: Summary Discourse Prometheus is the official Prometheus exporter for Discourse
:hammer_and_wrench: Repository Link https://github.com/discourse/discourse-prometheus
:open_book: Install Guide How to install plugins in Discourse

The Discourse Prometheus plugin collects key metrics from Discourse and exposes them in the /metrics path so prometheus can consume them.

These metrics can be used to Graph all sorts of data like:

image
image948×806 47.9 KB

Median and 99th percentile times for topic / categories / top and latest pages. Breaking down execution time between SQL/Redis and App.

image
image956×430 59.4 KB

Page view tracking

image
image952×394 34 KB

Error tracking

image
image958×453 34.9 KB

Ruby object space tracking including allocation rate, heaps and so on.

image
image954×449 34.9 KB

Hosted V8 memory statistics

image
image953×582 51.5 KB

Scheduled Job Queue and Sidekiq job durations and executions.

To see a full list of metrics available, install the plugin and visit SITENAME/metrics as an admin.

Out of the box we allow the metrics route to admins and private ips.

Discourse Prometheus is smart enough to aggregate data for all forked unicorn processes and present it as cohesive metrics on a single endpoint. We use it internally to keep track of our sites.

Sample dashboard at:

Discourse global setting called prometheus_trusted_ip_allowlist_regex (env: DISCOURSE_PROMETHEUS_TRUSTED_IP_ALLOWLIST_REGEX) is allowing to set Prometheus’s trusted IP addresses. The setting accepts regular expression to set advanced IP ranges. This is useful in a case when Prometheus IP address is dynamic.

51 Likes
99

I’m currently managing discourse on Kubernetes, running on multiple app and sidekiq pods. I have a couple of questions regarding the plugin:

  1. Does the plugin aggregate metrics from all the app pods? I’m assuming it does aggregate metrics for unicorn processes running on a single instance/pod.
  2. I’m curious about the reason behind observing timings for only some controller actions. This query is related to the code at discourse-prometheus/lib/collector.rb at main · discourse/discourse-prometheus · GitHub.
102

Hello,

Where can I find the setting prometheus_trusted_ip_allowlist_regex? :crying_cat_face:

image
image2040×854 35.1 KB

I’m using Discourse v3.4.0.beta3-dev

103

You have to set DISCOURSE_PROMETHEUS_TRUSTED_IP_ALLOWIST_REGEX in app.yml.

1 Like
104

Not sure what’s happening but this integration is not working anymore. I couldn’t get the dashboard in grafana to display anything… the /metrics does return something but anything beyond that does not really work

Many errors like the one below

Started GET "/metrics/api/v1/label/instance/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started GET "/metrics/api/v1/label/job/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views%7B%7D" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
  Rendered layout layouts/no_ember.html.erb (Duration: 21.1ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 26.0ms | GC: 0.0ms)
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
  Rendered layout layouts/no_ember.html.erb (Duration: 19.8ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 28.2ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 34.6ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 44.4ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 41.7ms | GC: 0.0ms)
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:07 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:08 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:08 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:08 +0000
  Rendered layout layouts/no_ember.html.erb (Duration: 23.6ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 24.9ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 19.9ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 21.6ms | GC: 0.0ms)
Started GET "/metrics/api/v1/label/job/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views%7B%7D" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started GET "/metrics/api/v1/label/instance/values?limit=40000&start=1760980620&end=1760982480&match%5B%5D=discourse_page_views" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
  Rendered layout layouts/no_ember.html.erb (Duration: 19.5ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 20.9ms | GC: 0.0ms)
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
Started POST "/metrics/api/v1/query_range" for 16.63.57.20 at 2025-10-20 17:47:37 +0000
  Rendered layout layouts/no_ember.html.erb (Duration: 22.4ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 22.0ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 40.0ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 37.0ms | GC: 0.0ms)
  Rendered layout layouts/no_ember.html.erb (Duration: 24.8ms | GC: 1.6ms)
105

Cross-posting this as I found a solution that worked for me Discourse Prometheus 404 metrics for Grafana - #2 by DevTeVe