随着Aspire发布preview5的发布,Microsoft.Extensions.ServiceDiscovery随之更新,
服务注册发现这个属于老掉牙的话题解决什么问题就不赘述了,这里主要讲讲Microsoft.Extensions.ServiceDiscovery(preview5)以及如何扩展其他的中间件的发现集成 .
Microsoft.Extensions.ServiceDiscovery官方默认提供的Config,DNS,YARP三种Provider,使用也比较简单 :
builder.Services.AddServiceDiscovery();
builder.Services.AddHttpClient<CatalogServiceClient>(static client =>
{
client.BaseAddress = new("http://todo");
});
builder.Services.ConfigureHttpClientDefaults(static http =>
{
// 全局对HttpClient启用服务发现
http.UseServiceDiscovery();
});
然后 appsettings.json 为名为 todo 的服务配置终结点：
"Services": {
"todo": {
"http": [
"http://localhost:5124"
]
}
}
然后使用服务发现:
#region 模拟服务端的todo接口:
var sampleTodos = new Todo[] {
new(1, "Walk the dog"),
new(2, "Do the dishes", DateOnly.FromDateTime(DateTime.Now)),
new(3, "Do the laundry", DateOnly.FromDateTime(DateTime.Now.AddDays(1))),
new(4, "Clean the bathroom"),
new(5, "Clean the car", DateOnly.FromDateTime(DateTime.Now.AddDays(2)))
};
var todosApi = app.MapGroup("/todos");
todosApi.MapGet("/", () => sampleTodos);
todosApi.MapGet("/{id}", (int id) =>
sampleTodos.FirstOrDefault(a => a.Id == id) is { } todo
? Results.Ok(todo)
: Results.NotFound());
#endregion
public record Todo(int Id, string? Title, DateOnly? DueBy = null, bool IsComplete = false);
[JsonSerializable(typeof(Todo[]))]
internal partial class AppJsonSerializerContext : JsonSerializerContext
{
}
#region 测试服务发现和负载
app.MapGet("/test", async (IHttpClientFactory clientFactory) =>
{
//这里服务发现将自动解析配置文件中的服务
var client = clientFactory.CreateClient("todo");
var response = awAIt client.GetAsync("/todos");
var todos = await response.Content.ReadAsStringAsync();
return Results.Content(todos, contentType: "application/json");
});
#endregion
运行程序后将会发现成功执行:
当然对于这样写死配置的服务发现一点都不灵活,因此应运而生了 YARP和DNS这些Provider, 目前服务注册发现使用Consul的还是挺多的,当然还有很多其他的轮子就不赘述了,这里我们来扩展一个Consul的服务发现Provider :
实现核心接口IServiceEndPointProvider
internal class ConsulServiceEndPointProvider(ServiceEndPointQuery query, IConsulClient consulClient, ILogger logger)
: IServiceEndPointProvider, IHostNameFeature
{
const string Name = "Consul";
private readonly string _serviceName = query.ServiceName;
private readonly IConsulClient _consulClient = consulClient;
private readonly ILogger _logger = logger;
public string HostName => query.ServiceName;
#pragma warning disable CA1816 // Dispose 方法应调用 SuppressFinalize
public ValueTask DisposeAsync() => default;
public async ValueTask PopulateAsync(IServiceEndPointBuilder endPoints, CancellationToken cancellationToken)
{
var flag = ServiceNameParts.TryParse(_serviceName, out var serviceNameParts);
var sum = 0;
if (flag)
{
var queryResult = await _consulClient.Health.Service(serviceNameParts.Host, string.Empty, true, cancellationToken);
foreach (var serviceEntry in queryResult.Response)
{
var address = $"{serviceEntry.Service.Address}:{serviceEntry.Service.Port}";
var isEndpoint = ServiceNameParts.TryCreateEndPoint(address, out var endPoint);
if (isEndpoint)
{
++sum;
var serviceEndPoint = ServiceEndPoint.Create(endPoint!);
serviceEndPoint.Features.Set<IServiceEndPointProvider>(this);
serviceEndPoint.Features.Set<IHostNameFeature>(this);
endPoints.EndPoints.Add(serviceEndPoint);
_logger.LogInformation($"ConsulServiceEndPointProvider Found Service {_serviceName}:{address}");
}
}
}
if (sum == 0)
{
_logger.LogWarning($"No ConsulServiceEndPointProvider were found for service '{_serviceName}' ('{HostName}').");
}
}
/// <inheritdoc/>
public override string ToString() => Name;
}
实现 IServiceEndPointProviderFactory:
internal class ConsulServiceEndPointProviderFactory(IConsulClient consulClient, ILogger<ConsulServiceEndPointProviderFactory> logger) : IServiceEndPointProviderFactory
{
private readonly IConsulClient _consulClient = consulClient;
private readonly ILogger<ConsulServiceEndPointProviderFactory> _logger = logger;
public bool TryCreateProvider(ServiceEndPointQuery query, [NotNullWhen(true)] out IServiceEndPointProvider? resolver)
{
resolver = new ConsulServiceEndPointProvider(query, _consulClient, _logger);
return true;
}
}
接着扩展一下IServiceCollection
public static IServiceCollection AddConsulServiceEndpointProvider(this IServiceCollection services)
{
services.AddServiceDiscoveryCore();
services.AddSingleton<IServiceEndPointProviderFactory, ConsulServiceEndPointProviderFactory>();
return services;
}
最后添加一行代码 :
// 使用Microsoft.Extensions.ServiceDiscovery实现负载均衡
builder.Services.AddServiceDiscovery()
.AddConfigurationServiceEndPointResolver() //config
.AddConsulServiceEndpointProvider(); //consul
下面是Consul中注册完成的服务:
然后我们请求 ./test 调用服务,观察调试日志,成功了!
完整的代码:
https://github.com/vipwan/Biwen.Microsoft.Extensions.ServiceDiscovery.Consul
当然你也可以直接使用nuget引用 Biwen.Microsoft.Extensions.ServiceDiscovery.Consul 我已经发布到了nuget上 , 最后因为Aspire还在不停的迭代所以Biwen.Microsoft.Extensions.ServiceDiscovery.Consul后面还会存在一些变化, 前面的几个早期版本我都做了适配以最新的为准
