How to use Grafana to create graphs with data from Spring Boot - spring-boot

Question

I am new to Grafana and Spring Boot. I am trying to create a Spring Boot application, and use Grafana SimpleJSON Datasource plugin to get data from my Spring Boot APIs and create graphs. I'm following instructions here https://grafana.com/grafana/plugins/grafana-simple-json-datasource/. Right now I am just hard-coding data into my Spring Boot App.
My question is - Are there other better plugins or approaches people would suggest me to use? SimpleJSON seems to require a very specific format of JSON response, and I don't see too many detailed docs online. Is there any way that I can be more free on my JSON responses of my APIs, and set the parameters needed to plot graphs in Grafana?
Thank you.

Answer 1

You can use Micrometer with Spring Boot Actuator framework to expose metric data to a time series database such as Prometheus. Or you can simply write log files, collect them with Promtail and store them in Loki.
At first this might seem like a lot of work to get these things running, but it might be worth it.
I found it surprisingly simple to get the whole monitoring stack running locally with docker-compose:
Add services grafana, prometheus, promtail and loki.
Configure each of them.
The docker-compose might look like this:
version: "3"
services:
prometheus:
image: prom/prometheus:latest
command:
- --config.file=/etc/prometheus/prometheus.yml
volumes:
- ./config/prometheus/prometheus_local.yml:/etc/prometheus/prometheus.yml
ports:
- "9090:9090"
loki:
depends_on:
- promtail
image: grafana/loki:latest
volumes:
- ./config/loki:/etc/loki
ports:
- "3100:3100"
command: -config.file=/etc/loki/loki-local-config.yaml
promtail:
image: grafana/promtail:latest
volumes:
- .log:/var/log
- ./config/promtail/promtail-docker-config.yaml:/etc/promtail/config.yml
command: -config.file=/etc/promtail/config.yml
grafana:
depends_on:
- prometheus
- loki
image: grafana/grafana:latest
volumes:
- ./config/grafana/grafana.ini:/etc/grafana/grafana.ini
- ./config/grafana/provisioning:/etc/grafana/provisioning
- ./config/grafana/dashboards:/etc/grafana/dashboards
ports:
- "3000:3000"
Sample config files for provisioning grafana can be found in the grafana git repository. Loki provides sample configurations for itself and promtail. For Prometheus, see here.
The official documentaion about installing Grafana with loki can be found here. There is also documentation about the Prometheus configuration.
Now you need to configure your application. Enable and expose the endpoint prometheus as described in the spring boot documention. Configure a log file appender to write the logs to the above configured log directory .log.
Your logs will now get collected by Promtail and sent to Loki. Metrics will get stored in Prometheus. You can use PromQL and LogQL to write Grafana queries and render the results in Grafana panels.
With this solution you can add tags to your data that can later be used by grafana.