gRPC service endpoint is not accessible via Kong Gateway - grpc

Question

gRPC services (developed in springboot) deployed as docker container on AWS linux (ec2). Started the docker image with port forwarding -p6565:6565.
Now when directly hit via BloomRPC on laptop, it worked : ec2.IP:6565 Package.Service.Method
Configured service & route in Kong:
{
"host": "ec2.IP",
"created_at": 1588403433,
"connect_timeout": 60000,
"id": "e657d8df-6247-458a-a8e8-bec00c41e03c",
"protocol": "grpc",
"name": "aws-grpc1",
"read_timeout": 60000,
"port": 6565,
"path": null,
"updated_at": 1588403433,
"retries": 5,
"write_timeout": 60000,
"tags": null,
"client_certificate": null
}
Route:
{
"strip_path": false,
"path_handling": "v0",
"updated_at": 1588403452,
"destinations": null,
"headers": null,
"protocols": [
"grpc",
"grpcs"
],
"created_at": 1588403452,
"snis": null,
"service": {
"id": "e657d8df-6247-458a-a8e8-bec00c41e03c"
},
"name": "aws-grpc1-route1",
"methods": null,
"preserve_host": false,
"regex_priority": 0,
"paths": [
"/grpc2"
],
"sources": null,
"id": "5739297e-3be7-4a0d-8afb-cfa8ed01cec2",
"https_redirect_status_code": 426,
"hosts": null,
"tags": null
}
Now hitting it via grpcurl -> its not working:
grpcurl -v -d "{}" -insecure ec2.ip:8443 package.service.pingMethod
Error invoking method "package.service.ping": target server does not expose service "package.service"
Here is kong config which looks related:
"proxy_listen": [
"0.0.0.0:8000 reuseport backlog=16384",
"0.0.0.0:8443 **http2** ssl reuseport backlog=16384"
],
So here are queries:
(1) can 8000 also be configured for https as insecure -> via passing a env KONG_PROXY_LISTEN variable at time of kong-container start by
-e "KONG_PROXY_LISTEN=0.0.0.0:8000 http2, 0.0.0.0:8443 http2 ssl"
Is this good to do?
(2) How to enable server side reflection? OR what is use of /grpc.reflection.v1alpha.ServerReflection/ServerReflectionInfo ?

Answer 1

You need to expose HTTP2 Proxy Listener for Kong.
You can refer to this one: https://konghq.com/blog/manage-grpc-services-kong/
In short, you need to add env variable details for KONG_PROXY_LISTEN like so:
-e "KONG_PROXY_LISTEN=0.0.0.0:8000 http2, 0.0.0.0:8443 http2 ssl, 0.0.0.0:9080 http2, 0.0.0.0:9081 http2 ssl"
Note: apparently Kong uses the ports 9080 for HTTP2 and 9081 for HTTP2 SSL. But I think this can be changed.
And also expose those 9080 and 9081 ports like so, this is example for docker run command:
-p 127.0.0.1:9080:9080 \
-p 127.0.0.1:9081:9081
And use the 9080 port in grpcurl when you try to request, like so:
grpcurl -v -d '{"name": "Ken"}' -plaintext localhost:9080 facade.GreetingService/SayHello

Answer 2

More updates:
gRPC deployed behind kong.ingress is working fine:
grpcurl -v -d "{\"greeting\":\"111\"}" -insecure acfb0xxxxx.elb.us-east-2.amazonaws.com:443 hello.HelloService.SayHello
Response:
Resolved method descriptor:
rpc SayHello ( .hello.HelloRequest ) returns ( .hello.HelloResponse );
Request metadata to send:
(empty)
Response headers received:
content-type: application/grpc
date: Sat, 02 May 2020 07:00:17 GMT
server: openresty
trailer: Grpc-Status
trailer: Grpc-Message
trailer: Grpc-Status-Details-Bin
via: kong/2.0.3
x-kong-proxy-latency: 1
x-kong-upstream-latency: 9
Response contents:
{
"reply": "hello 111"
}
Response trailers received:
(empty)
Sent 1 request and received 1 response
when configured on kong-API-gateway, it is not working:
grpcurl -v -d "{\"greeting\":\"111\"}" -insecure kong.ce-gateway.ip:8443 hello.HelloService.SayHello
Error invoking method "hello.HelloService.SayHello": failed to query for service descriptor "hello.HelloService": rpc error: code = Internal desc = An invalid response was received from the upstream server

Answer 3

Http2 is now enabled by default for Kong, but if you are having issues, a good place to start is to inspect the proxy_listeners section of the global config. In my case, I found that http2 was only enabled for the SSL port, and not for the non SSL. A good way to see the global config is to send a GET request to the root url of the admin api, for example GET http://localhost:8001/.