vansoni / spring-boot-default-metrics-example Goto Github PK

This repository demonstrates the most important default Spring Boot metrics which are enabled through the Spring Boot Actuator module:

• Spring MVC metrics
• Outbound request metrics for RestTemplate and WebClient
• JVM metrics

For a full explanation see the accompanying Spring Boot default metrics article at tomgregory.com or YouTube video.

To run this project you'll need:

• JDK 11+
• Docker

Build and run the project using Docker compose with the following command:

./gradlew assemble docker dockerComposeUp

This will startup:

• Spring Boot application at localhost:8080 exposing several APIs
  • API 1 is a simple GET API which adds a small random latency
  • API 2 is a simple GET API which adds a larger random latency
  • API 3 is a GET API that makes a request to another application using RestTemplate (see below)
  • Prometheus metrics for the Prometheus service to scrape (see below)
• nginx application at localhost:8081 to act as the 2nd application to be called using RestTemplate. It always returns a 200 response.
• Prometheus service at localhost:9090 which is preconfigured to scrape from the Spring Boot application

To avoid having to hit the APIs by hand in order to demonstrate the Prometheus metrics, a Gatling script is included which will hit all the different APIs multiple times over 30 seconds. See BasicSimulation.scala for details of how this is done.

Just run:

./gradlew gatlingRun

Try out these simple queries on Prometheus:

rate(http_server_requests_seconds_count[1m])

rate( http_server_requests_seconds_sum[1m]) / rate(http_server_requests_seconds_count[1m])

http_server_requests_seconds{quantile="0.95"}

rate(http_client_requests_seconds_sum[1m]) / rate(http_client_requests_seconds_count[1m])

sum(jvm_memory_used_bytes{area="heap"})

See more examples in the Spring Boot default metrics article at tomgregory.com

To stop all the applications in this project, just run:

./gradlew dockerComposeDown