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Build to Manage - Java application monitoring and logging lab

During this lab we will instrument a sample java application for logging to use with log analytics tools like Elastic stack as well as for monitoring with Prometheus and Grafana.

Instrumentation of the application code for monitoring and logging is part of the general concept we call Build to Manage. It specifies the practice of activities developers can do in order to provide manageability aspects as part of an application release.

Lab outline

  • Fork and clone the Github repository with a simple java servlet and review the source code
  • Configure a logging library and add log messages to the application code
  • Enable monitoring features of the WebSphere Liberty Profile
  • Build the application with Apache Maven
  • Configure and run Elastic stack in Docker Compose
  • Configure and run Prometheus and Grafana stack in Docker Compose
  • Build the java application container and integrate with Prometheus and ELK stack
  • Deploy to IBM Cloud Private using helm chart

Prerequisites

Install the following software on your workstation or use a provided VM.

  • JDK 8
  • Apache Maven
  • Docker
  • Docker Compose

Review the application code and run it locally

Logon to GitHub using your user and password. Access the following repository and click Fork.

https://github.com/rafal-szypulka/b2m-java

From now on you will work on your own fork of the application project

https://github.com/<username>/b2m-java

Clone b2m-java lab repository to your home directory using:

cd
git clone https://github.com/<username>/b2m-java

Most of the commands in this lab should be executed from the b2m-java directory:

cd b2m-java

Review the application code in src/main/java/application/rsapp/checkout.java. This minimalistic application simulates a transaction with random response time on the following URL:

http://localhost:9080/rsapp/checkout

About 5% of requests should return error and 500 HTTP response code.

Run the following command to build the java application and package it into target/rsapp.war:

mvn clean install

and then 

mvn liberty:run-server

to start the local WLP application server.

Use internet browser to access http://localhost:9080/rsapp/checkout The expected output is JSON formatted:

{"status":"RSAP0001I: Transaction OK","transactionTime":"22ms"}

or:

{"error":"RSAP0010E: Severe problem detected"}

Refresh the page a couple of times and you should see random transaction response times.