CODEWITHSUNDEEP
c#api-gatewayfailovermicrosoft-yarp
Guru_07
Guru_07

Reputation: 392

Microsoft C# .NET YARP 504 Gateway error and Failover

I am using Microsoft C# .NET YARP as an API gateway in front of ASP.NET Core Web API (latest version) with Swagger and Kestrel. YARP is used for intern redirections to many microservices.

Questions:

  1. I am facing 504 http API gateway error for requests that execute more than approx. 2 minutes from swagger UI. How do I set an increased timeout?

Ex: https://URL/swagger/index.html => Execute POST FUNCTION => YARP_API_GATEWAY => SERVICE_API_PORT

  1. If an internal service destination (endpoint) is down for any reason, how do I configure "Failover" to another destination?

Ex. configuration:

   "ReverseProxy": {
    "Routes": [
      {
        "RouteId": "Service1",
        "ClusterId": "ServiceCluster1",
        "Match": {
          "Path": "/api/Action1/{**rest}"
        },
        "Transforms": [
          { "RequestHeadersCopy": "true" },
          { "RequestHeaderOriginalHost": "true" }
        ]
      },
      {
        "RouteId": "Service2",
        "ClusterId": "ServiceCluster2",
        "Match": {
          "Path": "/api/Action2/{**rest}"
        },
        "Transforms": [
          { "RequestHeadersCopy": "true" },
          { "RequestHeaderOriginalHost": "true" }
        ]
      ],
    "Clusters": {
      "ServiceCluster1": {
        "Destinations": {
          "ServiceCluster1/destination1": {
            "Address": "http://localhost:5001/"
          },
          "ServiceCluster1/destination2": {
            "Address": "http://localhost:5002/"
          }
        }
      },
      "ServiceCluster2": {
        "Destinations": {
          "ServiceCluster2/destination1": {
            "Address": "http://localhost:5003/"
          },
          "ServiceCluster2/destination2": {
            "Address": "http://localhost:5004/"
          }
        }
      },
  }

Upvotes: 5

Views: 3870

Answers (2)

Marco Guevara
Marco Guevara

Reputation: 11

As per YARP documentation docs a Custom policy can be implemented by Inheriting from ILoadBalancingPolicy in Yarp.ReverseProxy.LoadBalancing namespace, You can incorporate a method within the implementation that issues a request to the desired endpoint before proceeding to the next destination, something like this:

private async Task<Bool> TryForwardToDestination(HttpContext context, DestinationState destinationToReach)

Upvotes: 0

Peter Wishart
Peter Wishart

Reputation: 12330

I've not used YARP but going from the docs it looks like:

  1. Default timeout for an outgoing HTTP request is 100 seconds. You can set the timeout per cluster via setting the HttpMessageInvoker timeout, e.g. add the following to the cluster config within each cluster:

         "HttpRequest": {
         "ActivityTimeout": "00:05:00"
     },

  2. You can use passive health checks to avoid destinations after a failed request (again, set at cluster level):

     "HealthCheck": {
   "Passive": {
     "Enabled": "true",
     "Policy": "TransportFailureRate",
     "ReactivationPeriod": "00:10:00"
   }
 },

For a faster response to the destination being down, you can configure regular active health checks.

Upvotes: 2

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