# Buggy code
async def _wait_for_launcher(self) -> None:
    log.debug("Waiting for Lavalink server to be ready")
    lastmessage = 0
    for i in itertools.cycle(range(50)):
        line = await self._proc.stdout.readline()
        if READY_LINE_RE.search(line):
            self.ready.set()
            break
        if self._proc.returncode is not None and lastmessage + 2 < time.time():
            # Avoid Console spam only print once every 2 seconds
            lastmessage = time.time()
            log.critical("Internal lavalink server exited early")
        if i == 49:
            # Sleep after 50 lines to prevent busylooping
            await asyncio.sleep(0.1)


# Traceback (RuntimeError)
Traceback (most recent call last):
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/discord/ext/commands/core.py", line 79, in wrapped
ret = await coro(*args, **kwargs)
File "/home/martinebots/martinebotscogs/cogs_modified/audio/audio.py", line 3183, in play
await self._enqueue_tracks(ctx, query)
File "/home/martinebots/martinebotscogs/cogs_modified/audio/audio.py", line 3885, in _enqueue_tracks
result, called_api = await self.music_cache.lavalink_query(ctx, player, query)
File "/home/martinebots/martinebotscogs/cogs_modified/audio/apis.py", line 911, in lavalink_query
results = await player.load_tracks(query)
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/lavalink/rest_api.py", line 300, in load_tracks
self.__check_node_ready()
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/lavalink/rest_api.py", line 268, in __check_node_ready
raise RuntimeError("Cannot execute REST request when node not ready.")
RuntimeError: Cannot execute REST request when node not ready.

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/discord/ext/commands/bot.py", line 863, in invoke
await ctx.command.invoke(ctx)
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/discord/ext/commands/core.py", line 728, in invoke
await injected(*ctx.args, **ctx.kwargs)
File "/home/martinebots/martinebotsvenv/lib/python3.7/site-packages/discord/ext/commands/core.py", line 88, in wrapped
raise CommandInvokeError(exc) from exc
discord.ext.commands.errors.CommandInvokeError: Command raised an exception: RuntimeError: Cannot execute REST request when node not ready.```

# Fixed code
async def _wait_for_launcher(self) -> None:
    log.debug("Waiting for Lavalink server to be ready")
    lastmessage = 0
    for i in itertools.cycle(range(50)):
        line = await self._proc.stdout.readline()
        if _RE_READY_LINE.search(line):
            self.ready.set()
            break
        if _FAILED_TO_START.search(line):
            raise RuntimeError(f"Lavalink failed to start: {line.decode().strip()}")
        if self._proc.returncode is not None and lastmessage + 2 < time.time():
            # Avoid Console spam only print once every 2 seconds
            lastmessage = time.time()
            log.critical("Internal lavalink server exited early")
        if i == 49:
            # Sleep after 50 lines to prevent busylooping
            await asyncio.sleep(0.1)