❯ Guillaume Laforge

Just a handy command-line tool

tools cli build

When developing new projects on my laptop, I often run some commands over and over again. Regardless of how far you’ve gone with your CI/CD pipelines, running commands locally without resorting to becoming a bash ninja can be pretty easy with… just!

just is a handy way to save and run project-specific commands

It’s a command-line tool that lets you define some commands to run (called recipes), in the form of a Makefile-inspired syntax. It even allows you to define dependencies between the various tasks of your justfile. It runs across all environments (Mac, Linux, Windows), and is quick to install. It loads .env files in which you can define variables specific to your project (other developers can have the same justfile but have variables specific for their projects)

Without further ado, let’s see it in action in my current project.

In my project, I have the following justfile:

set dotenv-load

alias r := run
alias b := build
alias d := deploy

default: run

run:
    ./gradlew -t run

build:
    gcloud builds submit -t $CLOUD_REGION-docker.pkg.dev/$PROJECT_ID/containers/$CONTAINER_NAME:v1

deploy: build
     gcloud run deploy bedtimestories --image=$CLOUD_REGION-docker.pkg.dev/$PROJECT_ID/containers/$CONTAINER_NAME:v1
  • The first instruction tells just to load an .env file.
  • The (optional) alias lines allow me to define shorcuts for commands that I run very often
  • There are three commands: run, build, and deploy:
    • run will run my application locally with gradle
    • build will containerize my app with my Dockerfile on Google Cloud Build
    • deploy depends on build and will deploy my container on Google Cloud Run

And now, I just run: just run, just deploy, or their shortcuts: just r or just d.

You also noticed the dollar variables which are interpolated from my .env file which contains the following variables:

PROJECT_ID=some-project-id
CLOUD_REGION=us-central1
CONTAINER_NAME=some-container-name

It’s just a new little handy tool in my toolbox!

Go check it out: just.systems. And have a look at the cheat sheet for more examples and syntax.