C# 具有TPL数据流的请求/响应模式
在使用TPL数据流库时,我们遇到了一个需要请求/响应模式的问题。我们的问题是我们有一个.NET核心API来调用依赖服务。依赖服务限制并发请求。我们的API不限制并发请求;因此,我们一次可以收到数千个请求。在这种情况下,依赖服务将在达到其限制后拒绝请求。因此,我们实现了一个C# 具有TPL数据流的请求/响应模式,c#,.net,task-parallel-library,tpl-dataflow,C#,.net,Task Parallel Library,Tpl Dataflow,在使用TPL数据流库时,我们遇到了一个需要请求/响应模式的问题。我们的问题是我们有一个.NET核心API来调用依赖服务。依赖服务限制并发请求。我们的API不限制并发请求;因此,我们一次可以收到数千个请求。在这种情况下,依赖服务将在达到其限制后拒绝请求。因此,我们实现了一个BufferBlock和一个TransformBlock。表演很扎实,效果很好。我们测试了我们的API前端,1000个用户每秒发出100个请求,0个问题。缓冲块缓冲请求,转换块并行执行所需数量的请求。依赖服务接收我们的请求并作出
BufferBlock
和一个TransformBlock
。表演很扎实,效果很好。我们测试了我们的API前端,1000个用户每秒发出100个请求,0个问题。缓冲块缓冲请求,转换块并行执行所需数量的请求。依赖服务接收我们的请求并作出响应。我们在转换块操作中返回该响应,一切正常。我们的问题是缓冲块和转换块断开连接,这意味着请求/响应不同步。我们遇到一个问题,请求将收到另一个请求者的响应(请参阅下面的代码)
具体到下面的代码,我们的问题在于GetContent
方法。该方法是从API中的服务层调用的,该层最终是从控制器调用的。下面的代码和服务层是单例的。缓冲区的sendaync
与转换块ReceiveAsync
断开连接,从而返回任意响应,而不一定是发出的请求
因此,我们的问题是:有没有一种方法可以使用数据流块来关联请求/响应?最终的目标是请求进入我们的API,发送到依赖服务,然后返回到客户机。下面是数据流实现的代码
public class HttpClientWrapper : IHttpClientManager
{
private readonly IConfiguration _configuration;
private readonly ITokenService _tokenService;
private HttpClient _client;
private BufferBlock<string> _bufferBlock;
private TransformBlock<string, JObject> _actionBlock;
public HttpClientWrapper(IConfiguration configuration, ITokenService tokenService)
{
_configuration = configuration;
_tokenService = tokenService;
_bufferBlock = new BufferBlock<string>();
var executionDataFlowBlockOptions = new ExecutionDataflowBlockOptions
{
MaxDegreeOfParallelism = 10
};
var dataFlowLinkOptions = new DataflowLinkOptions
{
PropagateCompletion = true
};
_actionBlock = new TransformBlock<string, JObject>(t => ProcessRequest(t),
executionDataFlowBlockOptions);
_bufferBlock.LinkTo(_actionBlock, dataFlowLinkOptions);
}
public void Connect()
{
_client = new HttpClient();
_client.DefaultRequestHeaders.Add("x-ms-client-application-name",
"ourappname");
}
public async Task<JObject> GetContent(string request)
{
await _bufferBlock.SendAsync(request);
var result = await _actionBlock.ReceiveAsync();
return result;
}
private async Task<JObject> ProcessRequest(string request)
{
if (_client == null)
{
Connect();
}
try
{
var accessToken = await _tokenService.GetTokenAsync(_configuration);
var httpRequestMessage = new HttpRequestMessage(HttpMethod.Post,
new Uri($"https://{_configuration.Uri}"));
// add the headers
httpRequestMessage.Headers.Add("Authorization", $"Bearer {accessToken}");
// add the request body
httpRequestMessage.Content = new StringContent(request, Encoding.UTF8,
"application/json");
var postRequest = await _client.SendAsync(httpRequestMessage);
var response = await postRequest.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<JObject>(response);
}
catch (Exception ex)
{
// log error
return new JObject();
}
}
}
公共类HttpClientWrapper:IHttpClientManager
{
专用只读IConfiguration\u配置;
专用只读ITokenService(令牌服务);
私有HttpClient \u客户端;
专用缓冲块_BufferBlock;
私有转换块_actionBlock;
公共HttpClientWrapper(IConfiguration配置,iTokeService令牌服务)
{
_配置=配置;
_令牌服务=令牌服务;
_bufferBlock=新的bufferBlock();
var executionDataFlowBlockOptions=新的executionDataFlowBlockOptions
{
MaxDegreeOfParallelism=10
};
var dataFlowLinkOptions=新的dataFlowLinkOptions
{
完成=真
};
_actionBlock=new TransformBlock(t=>ProcessRequest(t),
executionDataFlowBlockOptions);
_LinkTo(_actionBlock,dataFlowLinkOptions);
}
公共void Connect()
{
_client=新的HttpClient();
_client.DefaultRequestHeaders.Add(“x-ms-client-application-name”,
“公司名称”);
}
公共异步任务GetContent(字符串请求)
{
wait_bufferBlock.SendAsync(请求);
var result=await_actionBlock.ReceiveAsync();
返回结果;
}
专用异步任务ProcessRequest(字符串请求)
{
如果(_client==null)
{
Connect();
}
尝试
{
var accessToken=wait _tokenService.GetTokenAsync(_配置);
var httpRequestMessage=新的httpRequestMessage(HttpMethod.Post,
新Uri($“https://{u configuration.Uri}”);
//添加标题
httpRequestMessage.Headers.Add(“Authorization”、$“Bearer{accessToken}”);
//添加请求主体
httpRequestMessage.Content=新的StringContent(请求,Encoding.UTF8,
“应用程序/json”);
var postRequest=wait_client.sendaync(httpRequestMessage);
var response=await postRequest.Content.ReadAsStringAsync();
返回JsonConvert.DeserializeObject(响应);
}
捕获(例外情况除外)
{
//日志错误
返回新的JObject();
}
}
}
您需要做的是用id标记每个传入项,以便将数据输入与结果输出关联起来。下面是一个如何做到这一点的示例:
namespace ConcurrentFlows.DataflowJobs {
using System;
using System.Collections.Concurrent;
using System.Collections.Generic;
using System.Threading.Tasks;
using System.Threading.Tasks.Dataflow;
/// <summary>
/// A generic interface defining that:
/// for a specified input type => an awaitable result is produced.
/// </summary>
/// <typeparam name="TInput">The type of data to process.</typeparam>
/// <typeparam name="TOutput">The type of data the consumer expects back.</typeparam>
public interface IJobManager<TInput, TOutput> {
Task<TOutput> SubmitRequest(TInput data);
}
/// <summary>
/// A TPL-Dataflow based job manager.
/// </summary>
/// <typeparam name="TInput">The type of data to process.</typeparam>
/// <typeparam name="TOutput">The type of data the consumer expects back.</typeparam>
public class DataflowJobManager<TInput, TOutput> : IJobManager<TInput, TOutput> {
/// <summary>
/// It is anticipated that jobHandler is an injected
/// singleton instance of a Dataflow based 'calculator', though this implementation
/// does not depend on it being a singleton.
/// </summary>
/// <param name="jobHandler">A singleton Dataflow block through which all jobs are processed.</param>
public DataflowJobManager(IPropagatorBlock<KeyValuePair<Guid, TInput>, KeyValuePair<Guid, TOutput>> jobHandler) {
if (jobHandler == null) { throw new ArgumentException("Argument cannot be null.", "jobHandler"); }
this.JobHandler = JobHandler;
if (!alreadyLinked) {
JobHandler.LinkTo(ResultHandler, new DataflowLinkOptions() { PropagateCompletion = true });
alreadyLinked = true;
}
}
private static bool alreadyLinked = false;
/// <summary>
/// Submits the request to the JobHandler and asynchronously awaits the result.
/// </summary>
/// <param name="data">The input data to be processd.</param>
/// <returns></returns>
public async Task<TOutput> SubmitRequest(TInput data) {
var taggedData = TagInputData(data);
var job = CreateJob(taggedData);
Jobs.TryAdd(job.Key, job.Value);
await JobHandler.SendAsync(taggedData);
return await job.Value.Task;
}
private static ConcurrentDictionary<Guid, TaskCompletionSource<TOutput>> Jobs {
get;
} = new ConcurrentDictionary<Guid, TaskCompletionSource<TOutput>>();
private static ExecutionDataflowBlockOptions Options {
get;
} = GetResultHandlerOptions();
private static ITargetBlock<KeyValuePair<Guid, TOutput>> ResultHandler {
get;
} = CreateReplyHandler(Options);
private IPropagatorBlock<KeyValuePair<Guid, TInput>, KeyValuePair<Guid, TOutput>> JobHandler {
get;
}
private KeyValuePair<Guid, TInput> TagInputData(TInput data) {
var id = Guid.NewGuid();
return new KeyValuePair<Guid, TInput>(id, data);
}
private KeyValuePair<Guid, TaskCompletionSource<TOutput>> CreateJob(KeyValuePair<Guid, TInput> taggedData) {
var id = taggedData.Key;
var jobCompletionSource = new TaskCompletionSource<TOutput>();
return new KeyValuePair<Guid, TaskCompletionSource<TOutput>>(id, jobCompletionSource);
}
private static ExecutionDataflowBlockOptions GetResultHandlerOptions() {
return new ExecutionDataflowBlockOptions() {
MaxDegreeOfParallelism = Environment.ProcessorCount,
BoundedCapacity = 1000
};
}
private static ITargetBlock<KeyValuePair<Guid, TOutput>> CreateReplyHandler(ExecutionDataflowBlockOptions options) {
return new ActionBlock<KeyValuePair<Guid, TOutput>>((result) => {
RecieveOutput(result);
}, options);
}
private static void RecieveOutput(KeyValuePair<Guid, TOutput> result) {
var jobId = result.Key;
TaskCompletionSource<TOutput> jobCompletionSource;
if (!Jobs.TryRemove(jobId, out jobCompletionSource)) {
throw new InvalidOperationException($"The jobId: {jobId} was not found.");
}
var resultValue = result.Value;
jobCompletionSource.SetResult(resultValue);
}
}
}
命名空间ConcurrentFlows.DataflowJobs{
使用制度;
使用System.Collections.Concurrent;
使用System.Collections.Generic;
使用System.Threading.Tasks;
使用System.Threading.Tasks.Dataflow;
///
///定义以下内容的通用接口:
///对于指定的输入类型=>将生成一个等待的结果。
///
///要处理的数据类型。
///消费者期望返回的数据类型。
公共接口管理器{
任务提交请求(TInput数据);
}
///
///基于TPL数据流的作业管理器。
///
///要处理的数据类型。
///消费者期望返回的数据类型。
公共类DataflowJobManager:IJobManager{
///
///预计jobHandler是一个注入的
///基于数据流的“计算器”的单例实例
///不依赖于它是一个单身汉。
///
///处理所有作业的单例数据流块。
公共数据流作业管理器(IPropagatorBlock作业处理程序){
如果(jobHandler==null){抛出新的ArgumentException(“参数不能为null。”,“jobHandler”);}
this.JobHandler=JobHandler;
如果(!alreadyLink){
LinkTo(ResultHandler,newdataflowLinkOptions(){PropagateCompletion=true});
alreadyLinked=true;
}
}
私有静态bool alreadyLinked=false;
///
///将请求提交给JobHandler并异步等待结果。
///
///要处理的输入数据。
public class Worker: IWorker
{
private readonly IHttpClientManager _httpClient;
private readonly ITokenService _tokenService;
private readonly SemaphoreSlim _semaphore;
public Worker(IHttpClientManager httpClient, ITokenService tokenService)
{
_httpClient = httpClient;
_tokenService = tokenService;
// we want to limit the number of items here
_semaphore = new SemaphoreSlim(10);
}
public async Task<JObject> ProcessRequestAsync(string request, string route)
{
try
{
var accessToken = await _tokenService.GetTokenAsync(
_timeSeriesConfiguration.TenantId,
_timeSeriesConfiguration.ClientId,
_timeSeriesConfiguration.ClientSecret);
var cancellationToken = new CancellationTokenSource();
cancellationToken.CancelAfter(30000);
await _semaphore.WaitAsync(cancellationToken.Token);
var httpResponseMessage = await _httpClient.SendAsync(new HttpClientRequest
{
Method = HttpMethod.Post,
Uri = $"https://someuri/someroute",
Token = accessToken,
Content = request
});
var response = await httpResponseMessage.Content.ReadAsStringAsync();
return response;
}
catch (Exception ex)
{
// do some logging
throw;
}
finally
{
_semaphore.Release();
}
}
}
public class ThrottledExecution<T>
{
private readonly ActionBlock<Task<Task<T>>> _actionBlock;
private readonly CancellationToken _cancellationToken;
public ThrottledExecution(int concurrencyLevel, int minDurationMilliseconds = 0,
CancellationToken cancellationToken = default)
{
if (minDurationMilliseconds < 0) throw new ArgumentOutOfRangeException();
_actionBlock = new ActionBlock<Task<Task<T>>>(async task =>
{
try
{
var delay = Task.Delay(minDurationMilliseconds, cancellationToken);
task.RunSynchronously();
await task.Unwrap().ConfigureAwait(false);
await delay.ConfigureAwait(false);
}
catch { } // Ignore exceptions (errors are propagated through the task)
}, new ExecutionDataflowBlockOptions()
{
MaxDegreeOfParallelism = concurrencyLevel,
CancellationToken = cancellationToken,
});
_cancellationToken = cancellationToken;
}
public Task<T> Run(Func<Task<T>> function)
{
// Create a cold task (the function will be invoked later)
var task = new Task<Task<T>>(function, _cancellationToken);
var accepted = _actionBlock.Post(task);
_cancellationToken.ThrowIfCancellationRequested();
if (!accepted) throw new InvalidOperationException(
"The component has been marked as complete.");
return task.Unwrap();
}
public void Complete() => _actionBlock.Complete();
public Task Completion => _actionBlock.Completion;
}
private ThrottledExecution<JObject> throttledExecution
= new ThrottledExecution<JObject>(concurrencyLevel: 10);
public Task<JObject> GetContent(string request)
{
return throttledExecution.Run(() => ProcessRequest(request));
}