This project shows a sample integration with Prometheus and Grafana.
To see a demo running, you will need:
- a running app
- a running Prometheus server
- a running Grafana server
This project uses the spring-boot actuator, which can be configured to provide an endpoint for prometheus to consume.
Run the app and go to the following url to see the Prometheus metrics.
http://localhost:8080/actuator/prometheus
The app itself has an endpoint that will trigger various http status codes:
GET http://localhost:8080/api/echo/{httpStatusCode}
Call the endpoint a few times with 2xx / 4xx / 5xx error codes and refresh the Prometheus endpoint.
You should see new metrics with a http_server_requests_seconds prefix, indicating the response time of the server.
You should also see new metrics with a http_client_requests_seconds prefix, indicating the response time of
the endpoints we are calling.
Spring Boot 2.0 apps use Micrometer as a vendor-neutral application metrics facade.
Since we want to use Prometheus to scrape our metrics, the app has been setup with the
Micrometer Prometheus library.
You can see io.micrometer:micrometer-registry-prometheus in the build.gradle file.
Now let's setup Prometheus to consume the endpoint.
Prometheus will be run on a docker image.
Install and run docker.
This project has a sample Prometheus config file, prometheus.yml, which must be edited with your IP address.
Since Prometheus will be run on a Docker container, it won't have access to localhost.
Then run the command below to setup the Prometheus server on http://localhost:9090.
Make sure to replace {repoFilePath} with the path to your local copy of this repo.
docker run -d --name=prometheus -p 9090:9090 -v {repoFilePath}/prometheus.yml:/etc/prometheus/prometheus.yml prom/prometheus --config.file=/etc/prometheus/prometheus.yml
Once it's running, check it can access the metrics from the api.
Go to http://localhost:9090/graph, and in the Expression field, type up and click execute.
You should see
Element Value
------- -----
up{instance="{local ip}:8080",job="spring-actuator"} 1
If the value is not 1, make sure you have the right IP address.
You might need to update your prometheus.yml, delete the docker image and container and try again.
Once set up, let's set up Grafana to visualize the Prometheus data.
Grafana can be installed to a local instance:
http://docs.grafana.org/installation/mac/
Once installed, open http://localhost:3000 and log in.
Create a Prometheus data source to consume the Prometheus data.
Give it a name and set the url field to your Prometheus endpoint.
Click Save and Test and make sure it says
Data source is working
You can create a new dashboard to visualize the data. We'll be importing this existing dashboard for Micrometer instrumented applications
Go to to http://localhost:3000/dashboard/import and put 4701 in the
Grafana.com Dashboard field. Select the Prometheus data source you selected.
Once you press Import, Grafana should create a new dashboard that
graphs the data scraped by Prometheus from the Spring boot app.
You can create additional graphs to track your api calls using the http_client_requests metrics.