meitrex_backend

Local dev environment setup for the MEITREX project. Should not be used in production environments.

Get Started

This will contain a description on how get started to work as a backend dev. If you don't want to develop and only run the service, there is docker compose file provided.

Prerequisites

• Java

  We use Java 17. You can download the JDK here.

• Git

  We use Git as version control system. You can download it here. To be able to push and pull from GitHub, you will need to set up an SSH key. You can find a guide [here] (https://docs.github.com/en/authentication/connecting-to-github-with-ssh).

• IDE

  We use IntelliJ IDEA as IDE. You can download it here. As a student you can get a free license for the Ultimate Edition here. You can enable auto reload, where when you make changes in the code, the server will automatically reload the code. Here is a short guide how to enable it.

• Gradle

  We use Gradle as build tool. You can download it here.

• Docker

  We use Docker to run our microservices and the database. You can download it here.

Setting Up the Dev Environment

Cloning

This repository uses git submodules to be able to retrieve the repositories of all services into this repository when cloning. To do this, do the following:

1. As with any repo, clone it using git clone https://github.com/MEITREX/backend.git
2. Move into the repository (cd backend)
3. Initialize the submodules using git submodule init
4. Pull the submodules using git submodule update

Deployment

The local deployment of the backend is done in a few simple steps:

1. Start docker (desktop)
2. Create a network for the dapr sidecars to communicate: docker network create dapr-network
3. Execute the .bat or .sh file found under ./backend/compose.bat using compose.bat up --build (re-builds the containers) or compose.bat up (starts the containers without re-building if they already exist).

Some Hints/Common Issues

Error Unsupported class file major version 64 when compiling

Try to manually force gradle to use JDK 17 in the IntelliJ settings.

Debugging Services

To facilitate easy debugging of services, the docker containers are set up to expose all important ports to the host machine. This can easily be seen in Docker Desktop. Port mappings can also be found on the wiki.

This makes it possible for you to start a service in your favorite IDE (where you can set breakpoints etc.) and for that service to hook into the rest of the system.

• Firstly, start the whole backend as described above. Then you can stop the docker container of the service you want to debug (the database container needs to continue running!). You can then start the service you wish to debug on your host machine
• Make sure when you execute the service you wish to debug that it is being run in the "dev" profile. In IntelliJ the profile can be set in the "Run Configurations". Alternatively the profile can be set in the application.properties file
• Dapr PubSub Events do not work when debugging in this way