feat(irc): an ignore list for IRC nicknames; mostly to ignore bots

It is based on nicknames, not on hostnames or anything. So it is
rather sensitive to nickname changes. As such, it is meant to
ignore bots, not users.

dibridge/__main__.py

@@ -23,15 +23,23 @@
 @click.option("--irc-nick", help="IRC nick to use.", required=True)
 @click.option("--irc-channel", help="IRC channel to relay to, without the first '#'.", required=True)
 @click.option("--irc-puppet-ip-range", help="An IPv6 CIDR range to use for IRC puppets. (2001:A:B:C:D::/80)")
-def main(discord_token, discord_channel_id, irc_host, irc_port, irc_nick, irc_channel, irc_puppet_ip_range):
+@click.option("--irc-ignore-list", help="IRC nicknames to not relay messages for (comma separated, case-insensitive).")
+def main(
+    discord_token, discord_channel_id, irc_host, irc_port, irc_nick, irc_channel, irc_puppet_ip_range, irc_ignore_list
+):
     if irc_puppet_ip_range:
         irc_puppet_ip_range = ipaddress.ip_network(irc_puppet_ip_range)
         if irc_puppet_ip_range.num_addresses < 2**48:
             raise Exception("--irc-puppet-ip-range needs to be an IPv6 CIDR range of at least /80 or more.")
 
+    if irc_ignore_list.strip():
+        irc_ignore_list = [nickname.strip().lower() for nickname in irc_ignore_list.split(",") if nickname.strip()]
+    if not irc_ignore_list:
+        irc_ignore_list = None
+
     thread_d = threading.Thread(target=discord.start, args=[discord_token, discord_channel_id])
     thread_i = threading.Thread(
-        target=irc.start, args=[irc_host, irc_port, irc_nick, f"#{irc_channel}", irc_puppet_ip_range]
+        target=irc.start, args=[irc_host, irc_port, irc_nick, f"#{irc_channel}", irc_puppet_ip_range, irc_ignore_list]
     )
 
     thread_d.start()

dibridge/irc.py

@@ -13,7 +13,7 @@
 
 
 class IRCRelay(irc.client_aio.AioSimpleIRCClient):
-    def __init__(self, host, port, nickname, channel, puppet_ip_range):
+    def __init__(self, host, port, nickname, channel, puppet_ip_range, irc_ignore_list):
         irc.client.SimpleIRCClient.__init__(self)
 
         self._loop = asyncio.get_event_loop()
@@ -28,6 +28,7 @@ def __init__(self, host, port, nickname, channel, puppet_ip_range):
         self._channel = channel
         self._puppet_ip_range = puppet_ip_range
         self._pinger_task = None
+        self._irc_ignore_list = irc_ignore_list
 
         # List of users when they have last spoken.
         self._users_spoken = {}
@@ -55,6 +56,8 @@ def on_privmsg(self, _, event):
     def on_pubmsg(self, _, event):
         if event.target != self._channel:
             return
+        if event.source.nick.lower() in self._irc_ignore_list:
+            return
         asyncio.create_task(self._relay_mesage(event.source.nick, event.arguments[0]))
 
     def on_action(self, _, event):
@@ -243,10 +246,10 @@ def stop(self):
         asyncio.run_coroutine_threadsafe(self._stop(), self._loop)
 
 
-def start(host, port, name, channel, puppet_ip_range):
+def start(host, port, name, channel, puppet_ip_range, irc_ignore_list):
     asyncio.set_event_loop(asyncio.new_event_loop())
 
-    relay.IRC = IRCRelay(host, port, name, channel, puppet_ip_range)
+    relay.IRC = IRCRelay(host, port, name, channel, puppet_ip_range, irc_ignore_list)
 
     log.info("Connecting to IRC ...")
     asyncio.get_event_loop().run_until_complete(relay.IRC._connect())