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Cover image for Prometric-Go Part 2 — Full Hands-On Demo with Grafana, Prometheus & k6 📈
Md Asraful Haque (Sohel)
Md Asraful Haque (Sohel)

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Prometric-Go Part 2 — Full Hands-On Demo with Grafana, Prometheus & k6 📈

#go #prometheus #grafana #monitoring

This article is Part 2 of my Prometric-Go series.

If you haven't read Part 1 yet — the introduction to the library — you can check it out here:

🔗 https://dev.to/asraful_haque/simplifying-prometheus-metrics-in-go-with-prometric-go-22ef

👋 What we’re building in Part 2

In this article we will instrument a real Go API using prometric-go, collect metrics in Prometheus, and visualize everything in Grafana — including a load-test using k6 to generate traffic.

To make this super easy, I created a ready-to-run sample project:

🔗 GitHub Repo: https://github.com/peek8/prometric-go-sample

This repository contains:

Purpose Tool
Metric instrumentation prometric-go
Metrics storage Prometheus
Metrics visualization Grafana
Web API Go + net/http
Traffic Generation Grafan k6

k6 hits the API → API exposes metrics via /metrics → Prometheus scrapes → Grafana visualizes.

⚙️ Clone & Run the Sample 

$ git clone https://github.com/peek8/prometric-go-sample
$ cd prometric-go-sample
$ make run
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This will run the api server at port 7080. You can explore the prometheus metrics exposed by prometric-go library at url:

http://localhost:7080/metrics
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See the full metrics list exposed at prometric-go library readme

The K6 Script

I use Grafan k6 to generate traffic against the prometric API. This k6-scripts demonstrates a simple scenario that exercises the CRUD endpoints for Person objects.

What the script does

  • Creates some 50K Objects (ie Person) in ~20 mins (50000 iterations shared among 50 VUs, maxDuration: 10m).
  • Tries to get Person by Random Id for 10 mins (20.00 iterations/s for 10m0s, maxVUs: 10).
  • Tries to get Person list for 10 mins (10.00 iterations/s for 10m0s, maxVUs: 5).
  • Updates the Person for 10 mins (5.00 iterations/s for 2m0s, maxVUs: 5).
  • Deletes about 1500 Persons randomly within 10 mins (1500 iterations shared among 2 VUs,maxDuration: 10m0s).

These above iterations are enough to generate some adequate prometheus metrics which can be used to play with prometheus and grafana dashboard.

Run k6

  • Install Grafan k6 at your local machine and run the k6-scripts from the repo: 
$ k6 run ./scripts/k6-scripts.js
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And now if you hit the metric endpoint, you will see different metric values keep changing.

Prometheus and Grafana

Run Prometheus

Run prometheus using the prometheus.yml file:

$ docker run \
    -p 9090:9090 \
    -v ./resources/prometheus.yml:/etc/prometheus/prometheus.yml \
    prom/prometheus
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N.B: If you are using podman use host.containers.internal as targets at prometheus.yml file, ie:

targets: ["host.containers.internal:7080"]
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Run Grafana

Run Grafan using docker:

$ docker run -d -p 3000:3000 grafana/grafana
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Then grafana will be available at http://localhost:3000, use admin:admin as to login for the first time.

Import the included dashboard

Create Grafana Data Source

Import Grafana Dashboard

  • Open Grafana → Dashboards
  • Click Import
  • Upload grafana-dashboard.json
  • Select Prometheus datasource → prometric-k6 (or the one you use)

Voila, You’ll now see real-time metrics at the dashboard from the sample app:

Image Grafana Dashboard

💡 What You Learn From This Sample

Category Benefit
Go backend Clean way to expose metrics
Prometheus Scraping & querying the app
Grafana Dashboarding for API performance
k6 Generating programmable load
Observability From raw counters → real visual insights

🎁 Bonus: You Can Reuse This as a Template

The repo is intentionally simple, so you can fork it and adapt it for your own services.

  • Replace Person CRUD API with your own business logic
  • Keep the prometric-go instrumentation + dashboard
  • Add additional domain metrics as needed
  • Extend k6 tests to simulate real traffic

🌟 Final Thoughts

Prometheus + Grafana can feel complex when you start from scratch —
but with prometric-go, you get:

👌 Meaningful metrics by default
📦 Domain-specific metrics with 2–3 lines of code
🚀 Dashboards ready to plug into production

If you try out the sample, I’d love to hear your feedback!

⭐ If this helped you…

Support the project by giving a ⭐ to both repos:

🔗 https://github.com/peek8/prometric-go

🔗 https://github.com/peek8/prometric-go-sample

And feel free to reach out if you want help adding alerting rules, histograms tuning, Grafana provisioning, or Kubernetes deployment.

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