Actor termination

[tbuehlmann]

Linked Channel actors won't be terminated at any time. Memory leaks incoming.

[tbuehlmann]

Linked Channel actors will be terminate on Bot#terminate: ea3dd5c.

Still, no mechanism to regularly clean up wild, "orphaned" Channel actors.

[neektza]

Hey Tobias.

What's the case in which "orphaned" channel actors spring into existence? In other words, how do I know if there are any orphaned Channel actors?

After calling terminate on the bot, it seems it does indeed die, but all channels show it as if it's still connected.

[tbuehlmann]

"Orphaned" Channels spring into existence when for example leaving one or being kicked off one. The channels should be terminated when the Bot is terminated, but there's no mechanism that will terminate such inactive channels regularly.

One way would be to remember all channels on join/etc and check regularly if these channels are present in @channels. If not, terminate. Another rather meh way would be to scan through all Channel objects (using Objectspace and whatnot) and terminate the ones not being present in @channels.

[neektza]

I don't think I've hit the use case you described.

When I noticed that the bot is still showing as present on a channel even though I killed the Bot actor, I did not explicitly leave the channel (nor was I kicked from it). All I did was simply

bot = Vetinari::Bot.new do |c|
  # config
end

# later
bot.terminate

As far as I understand, after I kill the Bot actor, all Channel actors should die by consequence of being linked to the Bot as specified here.

What I don't understand is, why does the bot show as present, even though all the channel actors are (or at least, should be) dead. Where is this channel presence being maintained?

[tbuehlmann]

IIRC: Channels are linked to the Bot so if the Bot crashes, the channels shall crash and die as well. But just because Channels are linked to the Bot doesn't mean the Channels are terminated when the Bot is terminated. When terminating the Bot, the following calls happen:

Bot#finalize
@channels#terminate
@channels#finalize
#<Channel>#terminate
#<Channel>#terminate
#<Channel>#terminate
...

If the Bot parts a Channel, this Channel is simply removed from @channels (an Object of ChannelContainer. The Channel actor won't be terminated. Also, since that Channel is not in '@channels` anymore, it also won't be terminated when the Bot terminates.