CLI Development with Seq Logging

5分钟设置完整的命令行开发调试环境。

1. 启动Seq服务器

创建 docker-compose.yml:

version: '3.8'
services:
  seq:
    image: datalust/seq:latest
    ports:
      - "5341:80"
    environment:
      - ACCEPT_EULA=Y
      - SEQ_PASSWORD=dev123
    volumes:
      - seq-data:/data
    restart: unless-stopped

volumes:
  seq-data:

启动服务：

docker-compose up -d seq
# 访问 http://localhost:5341
# 用户名: admin, 密码: dev123

2. C# 项目集成

Serilog方式

dotnet add package Serilog.AspNetCore
dotnet add package Serilog.Sinks.Seq

方式1: 代码配置

using Serilog;

var builder = WebApplication.CreateBuilder(args);

Log.Logger = new LoggerConfiguration()
    .WriteTo.Console()
    .WriteTo.Seq("http://localhost:5341")
    .CreateLogger();

builder.Host.UseSerilog();
// ... 其他配置

方式2: appsettings.json配置

{
  "Serilog": {
    "WriteTo": [
      { "Name": "Console" },
      {
        "Name": "Seq",
        "Args": {
          "serverUrl": "http://localhost:5341",
          "apiKey": ""
        }
      }
    ],
    "Enrich": ["FromLogContext"],
    "Properties": {
      "Environment": "Development"
    }
  }
}

using Serilog;

var builder = WebApplication.CreateBuilder(args);

Log.Logger = new LoggerConfiguration()
    .ReadFrom.Configuration(builder.Configuration)
    .CreateLogger();

builder.Host.UseSerilog();
// ... 其他配置

NLog方式

dotnet add package NLog.Web.AspNetCore
dotnet add package NLog.Targets.Seq

方式1: 硬编码配置

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <targets>
    <target xsi:type="Console" name="console" />
    <target xsi:type="Seq" name="seq" serverUrl="http://localhost:5341" />
  </targets>
  <rules>
    <logger name="*" minlevel="Info" writeTo="console,seq" />
  </rules>
</nlog>

方式2: 从appsettings读取配置

<?xml version="1.0" encoding="utf-8" ?>
<nlog xmlns="http://www.nlog-project.org/schemas/NLog.xsd"
      xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance">
  <targets>
    <target xsi:type="Console" name="console" />
    <target xsi:type="Seq" name="seq" 
            serverUrl="${configsetting:name=Logging.Seq.ServerUrl}" 
            apiKey="${configsetting:name=Logging.Seq.ApiKey}" />
  </targets>
  <rules>
    <logger name="*" minlevel="Info" writeTo="console,seq" />
  </rules>
</nlog>

// appsettings.json
{
  "Logging": {
    "Seq": {
      "ServerUrl": "http://localhost:5341",
      "ApiKey": ""
    }
  }
}

// appsettings.Production.json
{
  "Logging": {
    "Seq": {
      "ServerUrl": "http://prod-seq:5341",
      "ApiKey": "prod-api-key"
    }
  }
}

using NLog.Web;

var builder = WebApplication.CreateBuilder(args);
builder.Host.UseNLog();
// ... 其他配置

使用示例 (两种方式通用)

public class OrderController : ControllerBase
{
    private readonly ILogger<OrderController> _logger;

    [HttpPost]
    public async Task<IActionResult> CreateOrder(Order order)
    {
        _logger.LogInformation("Creating order for user {UserId} with {ItemCount} items", 
            order.UserId, order.Items.Count);
        
        try
        {
            var result = await _orderService.CreateAsync(order);
            _logger.LogInformation("Order {OrderId} created successfully", result.Id);
            return Ok(result);
        }
        catch (Exception ex)
        {
            _logger.LogError(ex, "Failed to create order for user {UserId}", order.UserId);
            throw;
        }
    }
}

NLog结构化日志

// 使用NLog的原生API获得更多控制
private static readonly NLog.Logger logger = NLog.LogManager.GetCurrentClassLogger();

// 结构化日志
logger.Info("User {userId} performed {action} at {timestamp}", 
    user.Id, "login", DateTime.UtcNow);

// 作用域上下文
using (NLog.ScopeContext.PushProperty("OrderId", orderId))
{
    logger.Info("Processing started");
    // 处理逻辑
    logger.Info("Processing completed");
}

3. Flutter 项目集成

添加依赖

dependencies:
  http: ^1.1.0
  logging: ^1.2.0

简单日志发送

import 'dart:convert';
import 'package:http/http.dart' as http;
import 'package:logging/logging.dart';

void main() {
  Logger.root.level = Level.ALL;
  Logger.root.onRecord.listen((record) {
    // 控制台输出
    print('${record.level.name}: ${record.time}: ${record.message}');
    
    // 发送到Seq
    http.post(
      Uri.parse('http://localhost:5341/api/events/raw'),
      headers: {'Content-Type': 'application/json'},
      body: jsonEncode({
        '@t': record.time.toIso8601String(),
        '@l': record.level.name,
        '@m': record.message,
      }),
    );
  });

  runApp(MyApp());
}

4. CLI 调试技巧

替代断点调试

// 记录变量状态
_logger.LogDebug("Processing user {@User} with settings {@Settings}", user, settings);

// 性能监控
var sw = Stopwatch.StartNew();
await DoWork();
_logger.LogInformation("Work completed in {ElapsedMs}ms", sw.ElapsedMilliseconds);

// 条件日志
if (order.Total > 1000)
    _logger.LogWarning("High value order {OrderId}: {Total}", order.Id, order.Total);

Seq 查询技巧

• 搜索: UserId = 123
• 时间范围: 最近1小时
• 级别过滤: Warning以上
• 属性查看: 展开 @Properties

5. 开发命令

# 热重载开发
dotnet watch run

# Flutter热重载
flutter run

# 查看Seq日志
open http://localhost:5341

# 停止服务
docker-compose down

就这些。无需GUI调试器，Seq提供了更丰富的运行时洞察。