send_udp and get_host_udp_port indexed script data that is only created
on the first tick after patching, so calling them from on_init stopped
the server. They now return nothing until then.
Received packets were only polled once the host port was known, which
needs script commands. Poll whenever recv_udp exists instead, it does
nothing when the server runs without --enable-lua-udp.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Review feedback from Cooldude2606: UDP is most useful for arbitrary
blobs, so send_udp now takes any string and the packet is just
"channel?payload". Plugins get it as a udp-<channel> event with the
payload as a Buffer, or through handleUdp which logs handler errors
like handle does for ipc events.
The host socket is now opened when the RCON client is started and
closed where the RCON client is ended, matching how the RCON client is
handled, instead of being bound in start() and closed by _resetState.
The integration round trip moved to the FactorioServer tests, where it
sends a packet each way through a real server without the module.
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
Add opt-in UDP messaging between the host and the Factorio server using
the --enable-lua-udp option of Factorio 2.0.59+. When
factorio.enable_lua_udp is set the instance binds a localhost UDP socket,
starts Factorio with --enable-lua-udp on factorio.lua_udp_port (random
if null, like the RCON port) and tells the clusterio module the host port
via clusterio_private.update_instance.
Data from Factorio is sent with clusterio_api.send_udp(channel, data) in
the same IPC format as send_json, so plugins receive it through the
existing ipc-<channel> events. Packets not sent from the Lua UDP port
are ignored, as that is the only unauthenticated way into the IPC
handler. Data to Factorio is sent with the new sendUdp method on
instances and instance plugins, and is dispatched in-game as
on_udp_packet_received events by polling helpers.recv_udp every tick
from the clusterio module.
Plugins requiring UDP declare the new LuaUdp feature flag, which like
SavePatching and ScriptCommands refuses to load the plugin on instances
without the option enabled.
Verified against a headless 2.1.17 server: send_udp and recv_udp are
silent no-ops when the option is off, so a stale port in a save that is
moved to an instance without UDP does no harm. The integration test
matrix now starts the instance with UDP enabled on Factorio 2.0.59+ and
round trips a player event over it.
Closes#969
Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
The role of a slave as a host for Factorio servers is not well reflected
in its name and has caused confusion among users. Rename slave to host
to better reflect its role as a host of Factorio servers.
