Pupa

Pupa is a service template example. It's a simple service that can be used as a starting point for building more complex services.

Architecture Overview

This service template uses github.com/uber-go/dig as a Dependency Injection container, providing a clean and convenient way to register dependencies. The architecture follows low coupling principles, allowing each package to be self-contained and independent.

Key Features

• Dependency Injection: Uses dig for flexible dependency management.
• Database Integration: Includes MySQL with migrations as an example of database integration
• Server Implementation: Application implements example of gRPC server.
• Low Coupling: Each package can independently register its components. It's allow to use minimal coupling approach.
• Simple Addition of cmd Commands to the Application: Adding new cmd commands to the application is straightforward. Application is designed to be extensible, allowing you to easily introduce new commands without affecting the existing functionality.
• Easy testing: The dependency container allows do integration tests with any combination of dependencies.

Architectural Principles

The application follows minimal coupling principles, where each package can register its own:

• Services
• Repositories
• Dependencies
• Other components

For example, the dogs package demonstrates this by registering its own:

deps.ProvideAll(
    deps.Provide(NewServer),
    servers.GRPCServiceAdapter[*Server](),
    deps.Provide(NewRepository),
)

This approach ensures that:

• Packages are self-contained.
• No direct dependencies between packages.
• Removing a package from the application eliminates its dependencies from go.mod.
• Easy to add new features without modifying existing code.
• Clear separation of concerns.
• Testable components.

The DI container handles all dependency wiring, allowing packages to remain isolated while still working together cohesively.

Dev environment

Dev environment is based on Docker Compose for now. Maybe in the future we will use kind for Kubernetes.

Up dev and connect to the database:

make up
mysql -upupa -ppupa --host 127.0.0.1 --port 3306 -A pupa

Down dev:

make down

Run service

Describe application commands:

make help

Run the service:

make run

Run all tests:

make test

Try to make grpc calls manually:

grpcurl -plaintext -d '{"name": "Buddy"}' 127.0.0.1:8080 pupa.DogService.DogIsGoodBoyV1
grpcurl -plaintext -d '{"name": "Undefined"}' 127.0.0.1:8080 pupa.DogService.DogIsGoodBoyV1
grpcurl -plaintext -d '{"name": "Luna"}' 127.0.0.1:8080 pupa.DogService.DogIsGoodBoyV1

Or just run cmd command:

make wof