API returns a stream stops streaming after 8 seconds when accessed through grpc-gateway using HTTP

[sloppycoder]

I'm stumped by this problem, please help.

I used grapi to create a server skeleton, then implemented an API that returns a stream.

# proto file
rpc GetTopAccounts (GetTopAccountRequest) returns (stream Account) {

# implementation
for {
for _, acc := range accounts {
		err = svr.Send(acc)
		if err != nil {
			log.Printf("error streaming %+v", err)
			return nil
		}
	}

	log.Printf("iteration %d", i)
	time.Sleep(1000 * time.Millisecond)
}

When calling this API with golang gRPC client, things work fine. However, if I use curl to access the same API using HTTP, the response will stop streaming after exactly 8 seconds.

Here is my code repo
To run it:

go run ./cmd/server

#open another window

curl http://localhost:3100/top/10
...
{"result":{"account_id":"123"}}
{"result":{"account_id":"123"}}
{"result":{"account_id":"123"}}
# after exactly 8 seconds
curl: (18) transfer closed with outstanding read data remaining

the server prints this in console
2019/10/09 21:41:11 iteration 19
2019/10/09 21:41:11 error streaming rpc error: code = Canceled desc = context canceled

Meanwhile, running the gRPC client calling the same API can does not exhibit this problem

go run ./cmd/client
...
streams forever
...