# 设计时 DbContext 配置指引

> 目的：在执行 `dotnet ef` 命令时无需硬编码数据库连接，可根据 appsettings 与环境变量自动加载。本文覆盖环境变量设置、配置目录指定等细节。

## 三库迁移命令 只需更改 SnowflakeIds_App 迁移关键字
> 先生成迁移，再执行数据库更新。启动项目统一用 AdminApi 确保加载最新配置。

### 生成迁移
```bash
# App 主库
dotnet tool run dotnet-ef migrations add SnowflakeIds_App `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Api/TakeoutSaaS.AdminApi/TakeoutSaaS.AdminApi.csproj `
  --context TakeoutSaaS.Infrastructure.App.Persistence.TakeoutAppDbContext

# Identity 库
dotnet tool run dotnet-ef migrations add SnowflakeIds_Identity `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Api/TakeoutSaaS.AdminApi/TakeoutSaaS.AdminApi.csproj `
  --context TakeoutSaaS.Infrastructure.Identity.Persistence.IdentityDbContext

# Dictionary 库
dotnet tool run dotnet-ef migrations add SnowflakeIds_Dictionary `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Api/TakeoutSaaS.AdminApi/TakeoutSaaS.AdminApi.csproj `
  --context TakeoutSaaS.Infrastructure.Dictionary.Persistence.DictionaryDbContext
```

### 更新数据库
```bash
dotnet tool run dotnet-ef database update `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Api/TakeoutSaaS.AdminApi/TakeoutSaaS.AdminApi.csproj `
  --context TakeoutSaaS.Infrastructure.App.Persistence.TakeoutAppDbContext

dotnet tool run dotnet-ef database update `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Api/TakeoutSaaS.AdminApi/TakeoutSaaS.AdminApi.csproj `
  --context TakeoutSaaS.Infrastructure.Identity.Persistence.IdentityDbContext

dotnet tool run dotnet-ef database update `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Api/TakeoutSaaS.AdminApi/TakeoutSaaS.AdminApi.csproj `
  --context TakeoutSaaS.Infrastructure.Dictionary.Persistence.DictionaryDbContext
```

## 一、设计时工厂读取逻辑概述
设计时工厂（`DesignTimeDbContextFactoryBase<T>`）按下面顺序解析连接串：
1. 若设置了 `TAKEOUTSAAS_APP_CONNECTION` / `TAKEOUTSAAS_IDENTITY_CONNECTION` / `TAKEOUTSAAS_DICTIONARY_CONNECTION` 等环境变量，则优先使用。
2. 否则查找配置文件：
   - 从当前目录开始向上找到含 `TakeoutSaaS.sln` 的仓库根。
   - 依次检查 `src/Api/TakeoutSaaS.AdminApi`、`src/Api/TakeoutSaaS.UserApi`、`src/Api/TakeoutSaaS.MiniApi` 等目录，如果存在 `appsettings.json` 或 `appsettings.{Environment}.json` 则加载。
   - 若未找到，可通过环境变量 `TAKEOUTSAAS_APPSETTINGS_DIR` 指定包含 appsettings 文件的目录。

配置结构示例（出现在 AdminApi/MiniApi/UserApi 的 appsettings）：
```json
"Database": {
  "DataSources": {
    "AppDatabase": {
      "Write": "Host=120.53...;Database=takeout_app_db;Username=...;Password=...",
      "Reads": [
        "Host=120.53...;Database=takeout_app_db;Username=...;Password=..."
      ]
    },
    "IdentityDatabase": {
      "Write": "...",
      "Reads": [ "..." ]
    },
    "DictionaryDatabase": {
      "Write": "...",
      "Reads": [ "..." ]
    }
  }
}
```
设计时工厂会根据数据源名称（`DatabaseConstants.AppDataSource` 等）读取 `Write` 连接串，实现与运行时一致。

## 二、环境变量配置
### 1. Windows PowerShell
```powershell
# 指向包含 appsettings.json 的目录
$env:TAKEOUTSAAS_APPSETTINGS_DIR = \"D:\\HAZCode\\TakeOut\\src\\Api\\TakeoutSaaS.AdminApi\"

#（可选）覆盖 AppDatabase 连接串
$env:TAKEOUTSAAS_APP_CONNECTION = \"Host=120.53.222.17;Port=5432;Database=takeout_app_db;Username=app_user;Password=***\"

#（可选）覆盖 IdentityDatabase 连接串
$env:TAKEOUTSAAS_IDENTITY_CONNECTION = \"Host=...;Database=takeout_identity_db;Username=...;Password=...\"

#（可选）覆盖 DictionaryDatabase 连接串
$env:TAKEOUTSAAS_DICTIONARY_CONNECTION = "Host=...;Database=takeout_dictionary_db;Username=...;Password=..."
```

### 2. Linux / macOS
```bash
export TAKEOUTSAAS_APPSETTINGS_DIR=/home/user/TakeOut/src/Api/TakeoutSaaS.AdminApi
export TAKEOUTSAAS_APP_CONNECTION=\"Host=120.53.222.17;Port=5432;Database=takeout_app_db;Username=app_user;Password=***\"
export TAKEOUTSAAS_IDENTITY_CONNECTION=\"Host=...;Database=takeout_identity_db;Username=...;Password=...\"
export TAKEOUTSAAS_DICTIONARY_CONNECTION="Host=...;Database=takeout_dictionary_db;Username=...;Password=..."
```

> 注意：若设置了 `TAKEOUTSAAS_APP_CONNECTION`，则无需在 appsettings 中提供 `Write` 连接串，反之亦然。不要将明文密码写入代码仓库，建议使用 Secret Manager 或部署环境的安全存储。

## 三、执行脚本示例
完成上述环境变量配置后即可执行：
```powershell
# TakeoutAppDbContext（业务库）
dotnet tool run dotnet-ef database update `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --context TakeoutSaaS.Infrastructure.App.Persistence.TakeoutAppDbContext

# IdentityDbContext（身份库）
dotnet tool run dotnet-ef database update `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --context TakeoutSaaS.Infrastructure.Identity.Persistence.IdentityDbContext

# DictionaryDbContext（字典库）
dotnet tool run dotnet-ef database update `
  --project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --startup-project src/Infrastructure/TakeoutSaaS.Infrastructure/TakeoutSaaS.Infrastructure.csproj `
  --context TakeoutSaaS.Infrastructure.Dictionary.Persistence.DictionaryDbContext
```

若需迁移 Identity/Dictionary 等上下文，替换 `--context` 参数为对应类型即可。

## 四、常见问题
1. **未找到 appsettings**：确保 `TAKEOUTSAAS_APPSETTINGS_DIR` 指向存在 `appsettings.json` 的目录，或将命令在 API 项目目录中执行。
2. **密码错误**：确认远程 PostgreSQL 用户/密码是否与 appsettings 或环境变量一致，避免在 CLI 中使用默认的账号。
3. **多环境配置**：`ASPNETCORE_ENVIRONMENT` 变量可控制加载 `appsettings.{Environment}.json`；默认是 Development。