Introduction

This is a sample REST api on which you can try using Prometheus (Hardcoded) and Micrometer as discussed on the brownbag session

Setup if you want to run the code

1. Eclipse or STS or other IDE for java
2. Springboot plugin if you're not using STS
3. Maven 3+
4. Java 8, haven't tested yet on java 6 or 7
5. Postman or SOAPUI or browser for http request

Operations on the todo rest-api

localhost:8080

[GET] localhost:8080/v1/samplerest/todo/ping

Welcome!

[GET] localhost:8080/v1/samplerest/todo/list

[ { "id": 1, "description": "sample task" } ]

[POST] localhost:8080/v1/samplerest/todo/

• if using postman use body and raw for the payload (task to add)
• then should the response like this if you successfully added a task

{ "id": 3, "description": "test add" }

[DELETE] localhost:8080/v1/samplerest/todo/{id}

• v1/samplerest/todo/2 will delete task 2

[GET} localhost:8080/v1/prometheus

• should display the metrics provided by micrometer

for Prometheus server

1. go to https://prometheus.io/download/

2. if you're on Windows, download and extract prometheus-2.21.0-rc.0.windows-amd64.tar.gz

3. update prometheus.yml with these scrape configs if you want to pull the metrics from todo app

   metrics_path: '/v1/prometheus' static_configs:

   • targets: ['localhost:8080']

4. click prometheus.exe to start the Prometheus server

5. open localhost:9090/graph from the browser

6. if you call any operation on todo app, you should be able to see results executing query http_server_requests_seconds_bucket

Activity

1. Try the hardcoded version of creating the metrics

• comment out the dependency for micrometer/prometheus
• activate the dependency on pom.xml for Prometheus (metrics) stuff

2. Try to add Gauge and Summary metrics on com.ti.cop.opensource.model.Metrics

• you can use this link for reference: https://github.com/prometheus/client_java

3. populate the created metrics on com.ti.cop.opensource.controller.TodoController in any operation