Support for Reusable and Modular Justfiles in Monorepos (Namespaces)

[bukowa]

Originally posted in issue tracking mod, but I feel like it doesn't really belong there.

I am thinking about creating a reusable justfile that can work as a standalone file but can also be copied and imported where needed. For example, environment variables in each justfile represent a standalone application (created with a template) in subdirectories (like a monorepo). The main justfile at the root should be able to build all of them, but independently they should work as standalone applications. However, the root justfile should be able to modify the variables (it should also work for recipes) before building (e.g., to give them different names).

Imagine these justfiles created with a template (which anyone can provide with their frameworks, etc.) and placed in different subdirectories within a monorepo:

# app1/justfile
export APP_NAME := "app-name"

build:
    echo building $APP_NAME

# app2/justfile
export APP_NAME  := "app-name"

build:
    echo building $APP_NAME

# justfile
import 'app1/justfile' with {prefix_vars('app1'}
import 'app2/justfile' with {prefix_vars('app2'}

export app1_APP_NAME = "app-name-1"
export app2_APP_NAME = "app-name-2"

build:
    echo "Building...."
    just app1_build
    just app2_build

$ just build
Building...
building app-name-1
building app-name-2

In my opinion, this would allow the redistribution of applications with justfiles, which could create interesting reusable build processes. Keep in mind that the examples I gave were made up quickly.

[casey]

Not sure what the ultimate syntax should look like, but having a way of overriding variables in imported modules seems reasonable to me.

Maybe something like:

import 'app2/justfile' with APP_NAME = "app-name-1"

[bukowa]

Not sure what the ultimate syntax should look like, but having a way of overriding variables in imported modules seems reasonable to me.

Maybe something like:

import 'app2/justfile' with APP_NAME = "app-name-1"

I am thinking about {} because it would allow to implement more functions later.
So basically making it somehow extendable in the future where each function is implementation detail.
Trying to get down to key-value method as much as posisble.

import 'app1/justfile' with <func1>,<func2> ?

import 'app1/justfile' with {
    APP_NAME="?"
}

# chaining
import 'app1/justfile' with [
    custom_vars{
        APP_NAME="?"
    },
    renamed_recipes{
        build=build_app1
    },
    prefixed_vars{
       `APP1_`
    },
    future_idea{
        key=value,
        key2=value2
    },
]

[bukowa]

It looks a bit too complicated, it's better to work with modules and passing env vars explicitly but I'm still afraid that in a large nested structure I will accidentally overwrite the variables of a recipe that I don't want