On Mon, 7 May 2001, Dan Milstein wrote:
> Henri,
>
> Lots of good stuff. A few ideas/possibilities:
>
> 1) We've talked about specifying a response packet to indicate that the
> engine (or the web server) doesn't recognize a packet sent over. This would
> allow us much more flexiblity to add packet types to ajpv14, without having
> to make ajpv15,16, etc.
+1
In other words - both ends should deal with unknown packets - maybe by
sending back an "UNIMPLEMENTED" message.
> 2) What about specifying a separate, out of band control socket
> connection? If the web server opened up two connections, 1 for data, one
> for control, then we could have much better communication from the engine to
> the server (if it was shutting down contexts, for example). We could also
> have a heartbeat without interfering with the data channel.
I'm not sure - but I can see some benefits.
Right now we have (almost) bidirectional communication - the protocol is
based on message passing, and sort of "token"-based:
each side sends a message, then waits for a message.
The main reason for that is the single-threaded web server. ( Apache1.3,
maybe other servers ). It is a bit difficult to deal with 2 connections in
a single threaded env ( while keeping the code as simple as possible ).
My feeling is that for most needs of a servlet container we can deal with
the single socket protocol. I don't know any (major) use case or feature
of tomcat that would require the second socket.
( that doesn't mean I'm -1 on such thing )
Costin
