Go Microservices with Nix

This project demonstrates a microservices architecture using Go and Nix for reproducible builds and deployments.

Project Structure

.
├── flake.nix           # Main Nix configuration
├── apps/               # Application services
├── pkg/                # Shared Go packages
├── modules/            # NixOS modules
└── nix/                # Additional Nix configurations
    ├── ci.nix         # CI/CD configuration
    └── test-config.nix # NixOS module tests

Services

• API: HTTP API service (port 8080)
• Metrics: Metrics collection service (port 8081)
• Worker: Background job processor

Development

Prerequisites

• Nix with flakes enabled

Commands

1. Enter development shell:

nix develop

2. Build a service:

nix build .#api
nix build .#metrics
nix build .#worker

3. Build a container:

nix build .#containers.api
nix build .#containers.metrics
nix build .#containers.worker

4. Load container into Docker:

docker load < result

Testing

1. Run NixOS module tests:

nix-build nix/test-config.nix -A test

2. Build and run test VM:

nix-build nix/test-config.nix -A vm
./result/bin/run-*-vm

3. Run service tests:

nix build .#checks.x86_64-linux.test-all

Development Tips

• Use air for hot reloading during development
• Each service has its own go.mod for dependency management
• Shared code lives in the pkg directory
• Test new NixOS modules using nix/test-config.nix

Deployment

The project includes NixOS modules for deployment. Configure services in your NixOS configuration:

{ config, ... }:
{
  imports = [ ./modules ];
  
  services.myapp = {
    api.enable = true;
    metrics.enable = true;
    worker.enable = true;
  };
}

Container Images

Container images are built using Nix's dockerTools for maximum reproducibility. Images are minimal and contain only the necessary binaries.

Testing New Modules

When adding new modules or modifying existing ones:

1. Add the module to modules/
2. Update modules/default.nix to import it
3. Add configuration to nix/test-config.nix
4. Test using:

   nix-build nix/test-config.nix -A test

5. For interactive testing, run the VM:

   nix-build nix/test-config.nix -A vm
   ./result/bin/run-*-vm