How to handle RPC and REST calls to the API gateway(Krakend)?

[LioHub]

I'm trying to understand how to implement an api gateway that deals with microservices that expose rest and rpc endpoints.

• Expose REST endpoints to the client. Internally route to the REST or RPC microservices
• Expose REST and RPC endpoints to the client, route as necessary

We chose Krakend, I implemented the endpoints and configured rabbitmq, and it works, but I don't know how to give to the correct client from the queue. Can I give it back with some key?
@kpacha

first way
here i try set username with a queue and return the new username

{
      "endpoint": "/api/v1.0/setUserName/{reply_to}/{mess_id}/{route}",
      "method": "POST",
      "output_encoding": "json",
      "extra_config": {
        "github.com/devopsfaith/krakend/proxy": {
          "sequential": false
        }
      },
      "backend": [
        {
          "host": [
            "amqp://guest:guest@rabbitMQ:5672/"
          ],
          "url_pattern": "/",
          "encoding": "json",
          "sd": "static",
          "method": "GET",

          "disable_host_sanitize": true,
          "extra_config": {
            "github.com/devopsfaith/krakend-amqp/consume": {
              "name": "queue",
              "exchange": "exchange",
              "durable": true,
              "delete": false,
              "exclusive": false,
              "no_wait": true,
              "no_local": false,
              "routing_key": [
                "#"
              ],
              "prefetch_count": 10
            },

            "github.com/devopsfaith/krakend-amqp/produce": {
              "exchange": "exchange2",
              "durable": true,
              "delete": false,
              "exclusive": false,
              "no_wait": true,
              "mandatory": true,
              "immediate": false,
              "name": "queue2",

              "reply_to_key":"Reply_to",
              "msg_id_key":"Mess_id",
              "routing_key":"Route"
            }
          }

        }
      ]
    },

second way
producer
here i try set username with a queue

{
      "endpoint": "/api/v1.0/setUserName/{reply_to}/{mess_id}/{route}",
      "method": "POST",
      "headers_to_pass": ["Content-Type"],
      "backend": [
        {
          "host": [
            "amqp://guest:guest@rabbitMQ:5672/"
          ],
          "sd": "static",
          "encoding": "json",
          "disable_host_sanitize": true,
          "extra_config": {
            "github.com/devopsfaith/krakend-amqp/produce": {
              "name": "queue",
              "exchange": "exchange",
              "durable": true,
              "delete": false,
              "exclusive": false,
              "no_wait": true,
              "mandatory": true,
              "immediate": false,

              "reply_to_key":"Reply_to",
              "msg_id_key":"Mess_id",
              "routing_key":"Route"
            }
          }

        }
      ]
    },

consumer
here return the new username

    {
      "endpoint": "/api/v1.0/consumer/{queue_name}/{route}",
      "method": "GET",
      "backend": [
        {
          "host": [
            "amqp://guest:guest@rabbitMQ:5672/"
          ],
          "sd": "static",
          "encoding": "json",
          "disable_host_sanitize": true,
          "extra_config": {
            "github.com/devopsfaith/krakend-amqp/consume": {
              "name": "Queue_name",
              "exchange": "exchange2",
              "durable": true,
              "delete": false,
              "exclusive": false,
              "internal": false,
              "no_wait": true,
              "no_local": false,
              "routing_key": "Route",
              "prefetch_count": 10
            }
          }
        }
      ]
    }

thanks for help)

[kpacha]

hi, @LioHub and welcome to the krakend community!

1. An endpoint can't be a producer and a consumer at the same time.
2. The consumer can't be dynamically bound to different queues or routes depending on the request. The consumer is created when starting the gateway and it fetches messages at the background

TLDR; RPC over rest+amqp is not supported (yet)

cheers!

[robertotrgt]

Hi, is there some progress in implementing RPC over rest+amqp? very interested in this feature.

thanks.

[alombarte]

Hi @robertotrgt. It's not near. KrakenD 2.0 is about to be released, but this feature is not planned for 2.0 or the next version.

[ygtysr]

Hi, are you considering an implementation that will handle the responses of RPC and REST calls synchronously, as in the example here?