Development

    This section shows how to set up a development environment for Nebraska. Be also sure to read the contributing section for the general guidelines when contributing to Nebraska.

    Nebraska needs a running PostgresSQL database. Apart from that, the recommended way to work on it, is to run the backend with the noop authentication backend, and the frontend in a “watch” mode (where it auto-refreshes when there are changes to the frontend).

    Preparing the Database

    Nebraska uses the PostgreSQL database, and expects the used database to be set to the UTC timezone.

    By default Nebraska uses a database with the name nebraska, and nebraska_tests for the tests, respectively. For the main database, the full URL (with a different database name if desired) can be overridden by the environment variable NEBRASKA_DB_URL.

    For a quick setup of PostgreSQL for Nebraska’s development, you can use the postgres container as follows:

    • Start Postgres:

      • docker run --rm -d --name nebraska-postgres-dev -p 5432:5432 -e POSTGRES_PASSWORD=nebraska postgres
    • Create the database for Nebraska (by default it is nebraska):

      • psql postgres://postgres:[email protected]:5432/postgres -c 'create database nebraska;'
    • Set the timezone to Nebraska’s database:

    Development Quickstart

    • Go to the Nebraska project directory and run make

    • Run the backend (with the noop authentication): make run-backend

    • Then, in a different terminal tab/window, run the frontend: make run-frontend

    Any changes to the backend means that the make run-backend command should be run again. Changes to the frontend should be automatically re-built and the opened browser page should automatically refresh.

    Development Concepts

    Frontend

    The frontend side of Nebraska is a web application built using React and Material-UI.

    Backend

    The Nebraska backend is written in Go. The backend source code is structured as follows:

    • pkg/api: provides functionality to do CRUD operations on all elements found in Nebraska (applications, groups, channels, packages, etc), abstracting the rest of the components from the underlying datastore (PostgreSQL). It also controls the groups’ roll-out policy logic and the instances/events registration.

    • pkg/omaha: provides functionality to validate, handle, process and reply to Omaha updates and events requests received from the Omaha clients. It relies on the api package to get update packages, store events, or register instances when needed.

    • pkg/syncer: provides some functionality to synchronize packages available in the official Flatcar Container Linux channels, storing the references to them in your Nebraska datastore and even downloading packages payloads when configured to do so. It’s basically in charge of keeping up to date your the Flatcar Container Linux application in your Nebraska installation.

    • cmd/nebraska: is the main backend process, exposing the functionality described above in the different packages through its http server. It provides several http endpoints used to drive most of the functionality of the dashboard as well as handling the Omaha updates and events requests received from your servers and applications.

    • cmd/initdb: is just a helper to reset your database, and causing the migrations to be re-run. nebraska will apply all database migrations automatically, so this process should only be used to wipe out all your data and start from a clean state (you should probably never need it).