/Java-OTEL-POC

instrumenting spring-petclinic with opentelemetry java agent

Primary LanguageCSS

Spring PetClinic Sample Application Build Status

Understanding the Spring Petclinic application with a few diagrams

See the presentation here

Running petclinic locally

Petclinic is a Spring Boot application built using Maven. You can build a jar file and run it from the command line (it should work just as well with Java 8, 11 or 17):

git clone https://github.com/spring-projects/spring-petclinic.git
cd spring-petclinic
./mvnw package
java -jar target/*.jar

You can then access petclinic here: http://localhost:8080/

petclinic-screenshot

Or you can run it from Maven directly using the Spring Boot Maven plugin. If you do this it will pick up changes that you make in the project immediately (changes to Java source files require a compile as well - most people use an IDE for this):

./mvnw spring-boot:run

NOTE: Windows users should set git config core.autocrlf true to avoid format assertions failing the build (use --global to set that flag globally).

NOTE: If you prefer to use Gradle, you can build the app using ./gradlew build and look for the jar file in build/libs.

Building a Container

There is no Dockerfile in this project. You can build a container image (if you have a docker daemon) using the Spring Boot build plugin:

./mvnw spring-boot:build-image

In case you find a bug/suggested improvement for Spring Petclinic

Our issue tracker is available here: https://github.com/spring-projects/spring-petclinic/issues

Database configuration

In its default configuration, Petclinic uses an in-memory database (H2) which gets populated at startup with data. The h2 console is automatically exposed at http://localhost:8080/h2-console and it is possible to inspect the content of the database using the jdbc:h2:mem:testdb url.

A similar setup is provided for MySQL and PostgreSQL in case a persistent database configuration is needed. Note that whenever the database type is changed, the app needs to be run with a different profile: spring.profiles.active=mysql for MySQL or spring.profiles.active=postgres for PostgreSQL.

You could start MySQL or PostgreSQL locally with whatever installer works for your OS, or with docker:

docker run -e MYSQL_USER=petclinic -e MYSQL_PASSWORD=petclinic -e MYSQL_ROOT_PASSWORD=root -e MYSQL_DATABASE=petclinic -p 3306:3306 mysql:5.7.8

or

docker run -e POSTGRES_USER=petclinic -e POSTGRES_PASSWORD=petclinic -e POSTGRES_DB=petclinic -p 5432:5432 postgres:14.1

Further documentation is provided for MySQL and for PostgreSQL.

Compiling the CSS

There is a petclinic.css in src/main/resources/static/resources/css. It was generated from the petclinic.scss source, combined with the Bootstrap library. If you make changes to the scss, or upgrade Bootstrap, you will need to re-compile the CSS resources using the Maven profile "css", i.e. ./mvnw package -P css. There is no build profile for Gradle to compile the CSS.

Working with Petclinic in your IDE

Prerequisites

The following items should be installed in your system:

Steps:

  1. On the command line

    git clone https://github.com/spring-projects/spring-petclinic.git

  2. Inside Eclipse or STS

    File -> Import -> Maven -> Existing Maven project

    Then either build on the command line ./mvnw generate-resources or using the Eclipse launcher (right click on project and Run As -> Maven install) to generate the css. Run the application main method by right clicking on it and choosing Run As -> Java Application.

  3. Inside IntelliJ IDEA In the main menu, choose File -> Open and select the Petclinic pom.xml. Click on the Open button.

    CSS files are generated from the Maven build. You can either build them on the command line ./mvnw generate-resources or right click on the spring-petclinic project then Maven -> Generates sources and Update Folders.

    A run configuration named PetClinicApplication should have been created for you if you're using a recent Ultimate version. Otherwise, run the application by right clicking on the PetClinicApplication main class and choosing Run 'PetClinicApplication'.

  4. Navigate to Petclinic

    Visit http://localhost:8080 in your browser.

Looking for something in particular?

Spring Boot Configuration Class or Java property files
The Main Class PetClinicApplication
Properties Files application.properties
Caching CacheConfiguration

Interesting Spring Petclinic branches and forks

The Spring Petclinic "main" branch in the spring-projects GitHub org is the "canonical" implementation, currently based on Spring Boot and Thymeleaf. There are quite a few forks in a special GitHub org spring-petclinic. If you have a special interest in a different technology stack that could be used to implement the Pet Clinic then please join the community there.

Interaction with other open source projects

One of the best parts about working on the Spring Petclinic application is that we have the opportunity to work in direct contact with many Open Source projects. We found some bugs/suggested improvements on various topics such as Spring, Spring Data, Bean Validation and even Eclipse! In many cases, they've been fixed/implemented in just a few days. Here is a list of them:

Name Issue
Spring JDBC: simplify usage of NamedParameterJdbcTemplate SPR-10256 and SPR-10257
Bean Validation / Hibernate Validator: simplify Maven dependencies and backward compatibility HV-790 and HV-792
Spring Data: provide more flexibility when working with JPQL queries DATAJPA-292

Contributing

The issue tracker is the preferred channel for bug reports, features requests and submitting pull requests.

For pull requests, editor preferences are available in the editor config for easy use in common text editors. Read more and download plugins at https://editorconfig.org. If you have not previously done so, please fill out and submit the Contributor License Agreement.

License

The Spring PetClinic sample application is released under version 2.0 of the Apache License.