nginx sometimes close connection to grpc upstream when keepalive is set

[Maxim Dounin]

Hello!

On Sun, Jun 17, 2018 at 12:46:35PM -0400, peanutgyz wrote:

> when grpc server response
>  SETTINGS[0], WINDOW_UPDATE[0], PING[0], HEADERS[1], DATA[1], HEADERS[1]  in
> one tcp packet, 
> 
> nginx want to send settings ack and call function
> ngx_http_grpc_send_settings_ack, write some data in ctx->out
> 
> when finalize upstream grpc request, because out != NULL, nginx can't set
> connection to be keepalive and closed connection.
> 
> expect connection to be persistent .

There are situations when nginx won't be able to keep a connection 
alive.  These aren't likely to happen though, and not considered 
to be a problem.

-- 
Maxim Dounin
http://mdounin.ru/