逻辑应用程序执行直到错误 Http 获取请求解析 JSON

问题描述

在 Microsoft Azure 逻辑应用程序中，我有一个 do until 循环，它循环获取请求，直到它完成。但是 HTTP Get 请求给出了以下与超时有关的错误。似乎即使在 2 分钟内重试 4 次，http get 请求也会超时。

错误请求。 Http请求失败：服务器没有响应 超时限制。请参阅逻辑应用限制在 https://aka.ms/logic-apps-limits-and-config#http-limits。

操作失败。一个动作失败。没有依赖操作成功。
发生了 4 次重试。

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直到循环控制详述

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解决方法

如果打开Asynchronous Pattern后还是不行，应该是你的API没有按照asynchronous polling pattern设计。

从这张图可以知道，你的API需要先返回202，响应头需要包含location，这个location就是Azure轮询的URL地址逻辑应用。

请参考the following sample，但此示例可能有点过时，您可以参考它来设计您的 API。

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Diagnostics;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
using System.Web.Http;

namespace AsyncResponse.Controllers
{
    public class AsyncController : ApiController
    {
        //State dictionary for sample - stores the state of the working thread
        private static Dictionary<Guid,bool> runningTasks = new Dictionary<Guid,bool>();


        /// <summary>
        /// This is the method that starts the task running.  It creates a new thread to complete the work on,and returns an ID which can be passed in to check the status of the job.  
        /// In a real world scenario your dictionary may contain the object you want to return when the work is done.
        /// </summary>
        /// <returns>HTTP Response with needed headers</returns>
        [HttpPost]
        [Route("api/startwork")]
        public async Task<HttpResponseMessage> longrunningtask()
        {
            Guid id = Guid.NewGuid();  //Generate tracking Id
            runningTasks[id] = false;  //Job isn't done yet
            new Thread(() => doWork(id)).Start();   //Start the thread of work,but continue on before it completes
            HttpResponseMessage responseMessage = Request.CreateResponse(HttpStatusCode.Accepted);   
            responseMessage.Headers.Add("location",String.Format("{0}://{1}/api/status/{2}",Request.RequestUri.Scheme,Request.RequestUri.Host,id));  //Where the engine will poll to check status
            responseMessage.Headers.Add("retry-after","20");   //How many seconds it should wait (20 is default if not included)
            return responseMessage;
        }


        /// <summary>
        /// This is where the actual long running work would occur.
        /// </summary>
        /// <param name="id"></param>
        private void doWork(Guid id)
        {
            Debug.WriteLine("Starting work");
            Task.Delay(120000).Wait(); //Do work will work for 120 seconds)
            Debug.WriteLine("Work completed");
            runningTasks[id] = true;  //Set the flag to true - work done
        }

        /// <summary>
        /// Method to check the status of the job.  This is where the location header redirects to.
        /// </summary>
        /// <param name="id"></param>
        /// <returns></returns>
        [HttpGet]
        [Route("api/status/{id}")]
        [Swashbuckle.Swagger.Annotations.SwaggerResponse(HttpStatusCode.BadRequest,"No job exists with the specified id")]
        [Swashbuckle.Swagger.Annotations.SwaggerResponse(HttpStatusCode.Accepted,"The job is still running")]
        [Swashbuckle.Swagger.Annotations.SwaggerResponse(HttpStatusCode.OK,"The job has completed")]
        public HttpResponseMessage checkStatus([FromUri] Guid id)
        {
            //If the job is complete
            if(runningTasks.ContainsKey(id) && runningTasks[id])
            {
                runningTasks.Remove(id);
                return Request.CreateResponse(HttpStatusCode.OK,"Some data could be returned here");
            }
            //If the job is still running
            else if(runningTasks.ContainsKey(id))
            {
                HttpResponseMessage responseMessage = Request.CreateResponse(HttpStatusCode.Accepted);
                responseMessage.Headers.Add("location",id));  //Where the engine will poll to check status
                responseMessage.Headers.Add("retry-after","20");
                return responseMessage;
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadRequest,"No job exists with the specified ID");
            }
        }
    }
}