How to configure UDP services with Kong API Gateway

Since version 2.2 Kong API Gateway supports UDP services, but the documentation illustrates this
with a very complex Kubernetes setup. In this blog I will show you the easiest way to
configure a udp service.
Without further ado: to configure a UDP service in Kong,
you just have to do three things:

1. define a Kong service with the udp protocol
2. define a Kong route with the udp protocol
3. configure Kong to listen on UDP
   In this setup, I will configure the Google DNS nameservers as a udp service and
   route traffic from localport 5353.

define kong udp service

To define the kong UDP service, type:

$ curl -sS --fail 
     -X POST http://localhost:8001/services 
     -d name=google-dns 
     -d protocol=udp 
     -d host=8.8.8.8 
     -d port=53

define kong udp route

To define the kong UDP route to the service, type:

curl -sS --fail  
     -X POST http://localhost:8001/services/google-dns/routes 
     -H 'Content-Type: application/json' 
     -d '{"protocols": [ "udp"], "destinations": [{"port": 5353}]}'

configure Kong to listen on UDP

To configure Kong to listen on UDP, start kong with the property stream_listen set:

KONG_STREAM_LISTEN="0.0.0.0:5353 udp" kong ...

Bonus enable logging

The enable logging of udp requests, make you configure the udp protocol on the plugin too.

curl -sS --fail 
    -X POST http://localhost:8001/plugins 
    --data name=file-log 
    --data protocols=udp 
    --data protocols=http 
    --data protocols=https 
    --data config.path=/tmp/request.log

conclusion

The guide on Using UDP
in Kong is more a guide into the complexity of kubernetes. In this blog,
I showed you how easy it really is!
Image by Gerd Altmann from Pixabay