Xpra: Ticket #1838: completely skip server base classes

Similar to #1836 but for mixins (#1778 / #1761), we should be able to completely skip some of the server base classes. ie:

if remote-logging is disabled, don't inherit from LoggingServer
if mmap is disabled, don't inherit from MMAP_Server

etc

This would reduce the memory footprint, and increase the security (decreasing the attack surface): it is impossible to attack code which isn't there.

Could be done for the server by using a dynamic type for "server base" (see example patch). The client is not modular enough to support this sort of refactoring. (see #1796 for authentication handlers)

Fri, 11 May 2018 07:53:01 GMT - Antoine Martin: attachment set

attachment set to bases.patch

dynamic list of base classes

Fri, 11 May 2018 15:36:56 GMT - Antoine Martin: status, description changed

status changed from new to assigned
description modified (diff)

Huge commits making things modular in r19283 + r19282.

This may help with #1123, we just need a new "upgrade" argument for the cleanup method.

Fri, 11 May 2018 17:11:00 GMT - Antoine Martin:

As of r19284, the server can completely skip a number of modules:

xpra start --notifications=no --webcam=no --speaker=no --microphone=no \
    --file-transfer=no --printing=no --dbus-proxy=no \
    --remote-logging=no --mmap=no --clipboard=no --av-sync=no

(this will disable most of the optional mixins, both in the server base class and in the "client connection" instance)

Still TODO:

add test script running every combination possible (there are 2**10=1024!) to check for invalid attribute dependencies
ideally, deal with the "mmap_size" check more cleanly - meh
add switch for "idle", "client info" mixins
make control commands mixin optional (some subclasses assume this is always defined)
make it possible to disable the "commands", "encoding" and "network state" switches? (hard, especially for "encoding")
this probably caused #1841

Sun, 13 May 2018 15:14:11 GMT - Antoine Martin:

Regression: #1841, fixup: r19363

Tue, 22 May 2018 16:35:13 GMT - Antoine Martin:

Automated test script added in r19371, with some bug fixes included.

This script exposes lots of ugly dependency issues. (in particular with read-only mode, keyboard, etc) So many more bugs are left to fix..

Wed, 23 May 2018 10:28:52 GMT - Antoine Martin:

Updates:

r19373 + r19381 + r19388 + r19389 + r19467: fix readonly mode
r19400 skip shadow pointer polling when input devices are disabled
r19374 client bug when the desktop-size is not provided
r19375 fix wrong location for packet-queue
r19401 window model management refactoring
r19376 improve client warning message when the server does not forward any windows (--windows=no)
r19440 move encode work queue and thread to superclass (used by both clipboard and picture encoding)
r19379 + r19395 + r19406 major unit tests improvements
minor fixes: r19380, r19407, r19413, r19439, r19443, r19446 + r19447 + r19450, r19462, r19476, r19484
r19410 + r19452: audio vs av-sync fix
r19414 + r19415 + r19416 + r19417 + r19441 + r19442 + r19451 + r19482 + r19483 + r19485: run shadow unit tests on win32 and macos
r19475: test desktop and shadow servers with vnc client
r19448 + r19454: make it easier to run without first compiling with cython + installing
r19460 + r19461 + r19463 + r19469 + r19471 + r19473: rfb fixes
r19486: run fewer tests by default (slows down the build too much)
r19599 actually add test for "start-desktop"

Still TODO:

send_cursor might belong in the display rather than windows mixin?
the "desktop_size_unscaled" / "desktop_size" code in x11 server base is a bit ugly
same for "suspended" attribute used in source mixins: r19409
keys_pressed should be moved to the keyboard config: r19466
maybe verify that the window we forward is on the client's vfb screen (checking pixel colour at window location)
use super() more
add new build options to exclude some subsystems completely and avoid failures when they cannot be imported
batch delay and other data is missing from session info

Tue, 29 May 2018 15:38:24 GMT - Antoine Martin: summary changed

summary changed from completely skip base classes to completely skip server base classes

For the client, see #1861

Tue, 12 Jun 2018 13:18:51 GMT - Antoine Martin:

Ugly dependency utility cursor functions added: ticket:1658#comment:8.

Tue, 26 Jun 2018 09:54:31 GMT - Antoine Martin:

as of r19723 + r19724, we can run the server with some modules completely missing. Either not installing them (ie: build with --without-dbus - new switches added in r19725) or by nuking them afterwards (ie: rm -fr /usr/lib64/python2.7/site-packages/xpra/keyboard/).

This is true for the following xpra submodules: notifications, keyboard, clipboard, sound and dbus. The server runs but prints a warning if the settings or command line try to enable functionality that is not available, ie:

Warning: missing notifications module

r19726: the server can run without any codecs at all, this also means without any webcam or window forwarding
r19727: the client avoids sending keyboard and pointer events if the server doesn't know how to handle them
r19728: the client still runs without any of the optional modules (but those are still loaded - not the same as #1861)

Mon, 09 Jul 2018 14:50:12 GMT - Antoine Martin: owner, status changed

owner changed from Antoine Martin to J. Max Mena
status changed from assigned to new

@maxmylyn: FYI, feel free to close. (see comment:8)

Will follow up in #1913 (high memory usage).

Mon, 09 Jul 2018 16:26:13 GMT - J. Max Mena: status changed; resolution set

status changed from new to closed
resolution set to fixed

Noted and closed.

Mon, 03 Sep 2018 07:28:49 GMT - Antoine Martin:

r20282 does the same for RFB in shadow and desktop servers.

Mon, 03 Sep 2018 13:14:37 GMT - Norman Rasmussen:

Would you backport a fix to the v2.3.x branch (and maybe others?) to include calls to IdleMixin and ClipboardConnection in ClientConnection.get_info? I noticed that the data is missing :-(

Mon, 03 Sep 2018 13:14:46 GMT - Norman Rasmussen: cc set

cc norman@… added

Mon, 03 Sep 2018 14:27:44 GMT - Antoine Martin:

Would you backport a fix to the v2.3.x branch (and maybe others?) to include calls to IdleMixin and ClipboardConnection in ClientConnection.get_info? I noticed that the data is missing :-(

Done in r20284. @norman: does that work for you?

Sat, 29 Jun 2019 15:29:20 GMT - Antoine Martin:

Sat, 23 Jan 2021 05:35:07 GMT - migration script:

this ticket has been moved to: https://github.com/Xpra-org/xpra/issues/1838