Monorepo with Shared Configurations
New in version 2.10
This guide shows how to structure a monorepo where multiple services share common configurations.
Tip
Profiles provide another powerful way to organize development environments by allowing different variations to activate automatically based on your hostname, username, or manually via CLI flags. They work particularly well with monorepo structures for managing team-specific or environment-specific configurations.
Project Structure
my-monorepo/
├── devenv/
│ └── devenv.nix # Shared configurations
├── services/
│ ├── api/
│ │ ├── devenv.yaml
│ │ └── devenv.nix
│ └── frontend/
│ ├── devenv.yaml
│ └── devenv.nix
Shared Configuration
Create a shared configuration with common settings:
{ pkgs, ... }: {
packages = [
pkgs.curl
pkgs.jq
];
services.postgres = {
enable = true;
initialDatabases = [
{ name = "myapp"; }
];
};
pre-commit.hooks = {
prettier.enable = true;
nixpkgs-fmt.enable = true;
};
}
Service Configuration
API Service
Each service imports the shared configuration using an absolute import path. Paths starting with /
are resolved from the repository root (where .git
is located), allowing services in different directories to reference shared configurations consistently.
{ pkgs, ... }: {
# Node.js for the API
languages.javascript = {
enable = true;
package = pkgs.nodejs_20;
};
# API-specific environment
env = {
API_PORT = "3000";
SERVICE_NAME = "api";
};
# API scripts
scripts = {
dev.exec = "npm run dev";
test.exec = "npm test";
};
}
Frontend Service
{ pkgs, ... }: {
languages.javascript = {
enable = true;
package = pkgs.nodejs_20;
};
# Frontend scripts
scripts = {
dev.exec = "npm run dev";
build.exec = "npm run build";
};
}
Referencing the Repository Root
When working in a monorepo, you often need to reference paths relative to the repository root. Use config.git.root
to get the absolute path to the git repository root.
This is particularly useful for running processes from specific directories:
{ pkgs, config, ... }: {
processes.api.exec = {
exec = "npm run dev";
cwd = "${config.git.root}/services/api";
};
processes.frontend.exec = {
exec = "npm run dev";
cwd = "${config.git.root}/services/frontend";
};
}
This allows you to run multiple service processes from a single devenv shell, regardless of which directory you're in.
Working with Services
Enter a specific service environment:
The API service will have access to:
- All packages from
shared/devenv.nix
(git, curl, jq) - The PostgreSQL database service
- Common environment variables (PROJECT_NAME, ENVIRONMENT, DATABASE_URL)
- Its own specific settings (API_PORT, SERVICE_NAME)
Similarly, the frontend service inherits the shared configuration while maintaining its own specific settings.