---
title: Lifecycle and DI
description: Container registration graph and lifecycle semantics for database services
deprecated: true
supersededBy: ['/docs/grove']
---

## Preferred Pattern

Use constructor registration and type-based injection as the default style.

```go
// Register constructors
forge.ProvideConstructor(c, func(db *Database, logger forge.Logger) *UserService {
    return &UserService{db: db, logger: logger}
})
// Resolve by type (no string keys needed)
userService, err := forge.InjectType[*UserService](c)

eventBus, _ := vessel.InjectType[interfaces.EventBus](app.Container())
```

## Extension Registration Graph

`database.Extension.Register(app)` performs:

1. configuration load and validation
2. eager registration of `*DatabaseManager`
3. registration of default `Database` accessor
4. registration of type-specific accessor for default DB type:
   - SQL default -> `*bun.DB`
   - Mongo default -> `*mongo.Client`
   - Redis default -> `redis.UniversalClient`

## Key Service Identifiers

Constants in package:

- `database.ManagerKey`
- `database.DatabaseKey`
- `database.SQLKey`
- `database.MongoKey`
- `database.RedisKey`

Primary resolution path in modern code should still be type-based helpers.

## Runtime Lifecycle

- `DatabaseManager.Start(ctx)`:
  - marks manager started
  - opens all registered databases (idempotent)
- `DatabaseManager.Stop(ctx)`:
  - marks manager stopped
  - closes all databases
- `DatabaseManager.Health(ctx)`:
  - fails if any registered database is unhealthy

Extension-level lifecycle methods only mark extension started/stopped; manager owns connection lifecycle.

## Recommended Access Patterns

### By Type + Name (Best for multi-db)

```go
manager, _ := database.GetManager(app.Container())
primary, _ := manager.SQL("primary")
analytics, _ := manager.Mongo("analytics")
cache, _ := manager.Redis("cache")
```

### Through Helpers

```go
primary, _ := database.GetSQL(app.Container(), "primary")
cache, _ := database.GetRedis(app.Container(), "cache")
```

### App-Level Convenience

```go
primary, _ := database.GetSQLFromApp(app, "primary")
```

## When Registering Your Own Services

Inject `*database.DatabaseManager` and resolve named DBs inside constructors. This keeps your service constructors explicit and avoids implicit assumptions about default DB type.