Re: Adding SPICE support to Guacamole - spice-glib

[Nick Couchman <vnick@xxxxxxxxxx>]

On Thu, Jan 7, 2021 at 3:41 PM Nick Couchman <vnick@xxxxxxxxxx> wrote:

On Thu, Jan 7, 2021 at 3:21 PM Marc-André Lureau <marcandre.lureau@xxxxxxxxx> wrote:

Hi

On Fri, Jan 8, 2021 at 12:07 AM Nick Couchman <vnick@xxxxxxxxxx> wrote:

Hey, everyone,

I'm a contributor to the Guacamole project, and am currently working on adding support for the SPICE protocol to Guacamole. If you haven't heard of Guacamole, it is a protocol and associated software components for making various remote desktop interfaces available via native HTML5 in browsers. I realize that there is already a spice-html5 client, but, for various reasons, we'd like to add the SPICE support to Guacamole, as well.

Within Guacamole, the clients for the individual protocols are implemented in a daemon - guacd - that is written in C. It accesses the various remote desktop protocols that we support (VNC, RDP, SSH, and Telnet, today) and does the translation to the Guacamole protocol. So, I am attempting to write the SPICE client for this using the spice-glib library.

I'm running into an issue with the code I've written thus far. I've followed API documentation and some code examples, and I have it to where I'm configuring all of the required pieces - hostname/IP, tls-port, password, etc. I've set up the handlers for the session (channel-event) and for the channels. When I attempt to connect, the SPICE client starts up, the session starts/connects, and I see the main channel get created, but the connection never progresses after that. As far as I can tell, it doesn't even try any sort of connection to the SPICE server - I don't see any network traffic going to the SPICE server, and it never progresses past that point. I'm not seeing any errors - nothing that indicates it's tried and failed, or is expecting additional input, or anything like that.

I'm happy to share code if anyone is interested in looking at what I've done so far, or if anyone has any generic hints as to what I might check or resources that are helpful in writing a C-based client for SPICE, I'd greatly appreciate the insight and help. I'm sure there's something reasonably simple that I'm not doing, or doing out of order, but I'm a bit stumped at the moment.

Spice uses multiple connections which are called channels for the various streams. You need to get and listen for available channels on the SpiceSession.

Thanks for the quick response, Marc-Andre. Yes, I've got a handler that is supposed to listen for each of the channels to be created and then add the signal handlers for each of those channels (and connect to them, where applicable). The main channel is the only one that I ever see get created, after running "spice_session_connect(session)" on the SpiceSession that gets started. I never see the Display, Cursor, Input, Playback, Record, or WebDav channels get created.

 

Just to add to this - I set the "SPICE_DEBUG" environment variable to get a little more debugging, and these are the debug messages I get:

(process:129359): GSpice-DEBUG: 22:02:18.289: spice-session.c:289 New session (compiled from package spice-gtk 0.35)
(process:129359): GSpice-DEBUG: 22:02:18.289: spice-session.c:293 Supported channels: main, display, inputs, cursor, playback, record, smartcard, usbredir

(process:129359): GSpice-DEBUG: 22:02:18.291: spice-session.c:1774 no migration in progress
(process:129359): GSpice-DEBUG: 22:02:18.291: spice-channel.c:141 main-1:0: spice_channel_constructed
(process:129359): GSpice-DEBUG: 22:02:18.291: spice-session.c:2294 main-1:0: new main channel, switching

And that's the last of the debug I get from SPICE - nothing more after that. I'm wading through the spice-gtk code trying to figure out the code flow there to see where it might be hanging/stopping, and what it's waiting for.

-Nick

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