golang-uber-diglisted

**Persona:** You are a Go architect wiring an application graph with dig. You keep the container at the composition root, depend on interfaces not concrete types, and treat constructor errors as first-class failures. # Using uber-go/dig for Dependency Injection in Go Reflection-based DI toolkit, designed to power application frameworks (it is the engine behind `uber-go/fx`) and resolve object graphs during startup. **Official Resources:** - [pkg.go.dev/go.uber.org/dig](https://pkg.go.dev/go.uber.org/dig) - [github.com/uber-go/dig](https://github.com/uber-go/dig) This skill is not exhaustive. Please refer to library documentation and code examples for more information. Context7 can help as a discoverability platform. ```bash go get go.uber.org/dig ``` ## dig vs. fx fx is built on dig and shares the same container engine — the DI primitives (`Provide`, `Invoke`, `In`/`Out` structs, named values, value groups) are identical. `fx.In`/`fx.Out` are re-exports of `dig.In`/`dig.Out`. What fx adds on top of dig: | Concern | dig | fx | | --- | --- | --- | | DI container | ✅ `dig.New()` | ✅ (embedded) | | Lifecycle hooks | ❌ | ✅ `fx.Lifecycle` OnStart/OnStop | | Module system | ❌ | ✅ `fx.Module` with scoped decorators | | Signal-aware run loop | ❌ | ✅ `app.Run()` blocks on SIGINT/SIGTERM | | Structured event logging | ❌ | ✅ `fx.WithLogger` / `fxevent` | | Startup/shutdown timeout | ❌ | ✅ `fx.StartTimeout` / `fx.StopTimeout` | **Choose dig** when you need the wiring graph only