chat_archiver: Download each seen emote

so we have a permanent record, in case they're deleted or changed later

chat_archiver/chat_archiver/main.py

@@ -18,12 +18,13 @@ from uuid import uuid4
 import gevent.event
 import gevent.queue
 
-from common import ensure_directory, listdir
+from common import ensure_directory, listdir, rename
 from common.chat import BATCH_INTERVAL, format_batch, get_batch_files, merge_messages
 
 from girc import Client
 from monotonic import monotonic
 import prometheus_client as prom
+import requests
 
 
 # These are known to arrive up to MAX_DELAY after their actual time
@@ -117,6 +118,7 @@ class Archiver(object):
 		self.name = name
 		self.messages = gevent.queue.Queue()
 		self.channel = channel
+		self.base_dir = base_dir
 		self.path = os.path.join(base_dir, channel, "chat")
 		
 		self.stopping = gevent.event.Event()
@@ -212,6 +214,11 @@ class Archiver(object):
 			self.logger.debug("Got message: {}".format(data))
 			messages_received.labels(channel=self.channel, client=id(self), command=message.command).inc()
 
+			if data['tags'] and 'emotes' in data['tags']:
+				emote_specs = data['tags']['emotes'].split('/')
+				emote_ids = [emote_spec.split(':')[0] for emote_spec in emote_specs]
+				ensure_emotes(self.base_dir, emote_ids)
+
 			if data['tags'] and 'tmi-sent-ts' in data['tags']:
 				# explicit server time is available
 				timestamp = int(data['tags']['tmi-sent-ts']) / 1000. # original is int ms
@@ -268,6 +275,53 @@ class Archiver(object):
 		self.client.stop()
 
 
+def atomic_write(filepath, content):
+	temp_path = "{}.{}.temp".format(filepath, uuid4())
+	ensure_directory(filepath)
+	with open(temp_path, 'wb') as f:
+		f.write(content)
+	rename(temp_path, filepath)
+
+
+_EMOTES_RUNNING = {} # map (base_dir, emote id, theme, scale) -> in-progress greenlet fetching that path
+def ensure_emotes(base_dir, emote_ids):
+	"""Tries to download given emote from twitch if it doesn't already exist.
+	This happens in the background and errors are ignored.
+	"""
+	def _ensure_emote(emote_id, theme, scale):
+		try:
+			url = "https://static-cdn.jtvnw.net/emoticons/v2/{}/default/{}/{}".format(emote_id, theme, scale)
+			path = os.path.join(base_dir, "emotes", emote_id, "{}-{}".format(theme, scale))
+			if os.path.exists(path):
+				logging.debug("Emote {} already exists".format(path))
+				return
+			logging.info("Fetching emote from {}".format(url))
+			try:
+				response = requests.get(url)
+			except Exception:
+				logging.warning("Exception while fetching emote from {}".format(url), exc_info=True)
+				return
+			if not response.ok:
+				logging.warning("Error {} while fetching emote from {}: {}".format(response.status_code, url, response.text))
+				return
+			atomic_write(path, response.content)
+			logging.info("Saved emote {}".format(path))
+		finally:
+			assert _EMOTES_RUNNING[base_dir, emote_id, theme, scale] is gevent.getcurrent()
+			del _EMOTES_RUNNING[base_dir, emote_id, theme, scale]
+
+	for emote_id in emote_ids:
+		for theme in ('light', 'dark'):
+			for scale in ('1.0', '2.0', '3.0'):
+				# to prevent downloading the same emote twice because the first download isn't finished yet,
+				# check if it's already running.
+				key = base_dir, emote_id, theme, scale
+				if key not in _EMOTES_RUNNING:
+					_EMOTES_RUNNING[key] = gevent.spawn(_ensure_emote, emote_id, theme, scale)
+				else:
+					logging.debug("Skipping checking emote with key {} - already running".format(key))
+
+
 def write_batch(path, batch_time, messages, size_histogram=None):
 	"""Batches are named PATH/YYYY-MM-DDTHH/MM:SS-HASH.json"""
 	output = (format_batch(messages) + '\n').encode('utf-8')
@@ -281,11 +335,7 @@ def write_batch(path, batch_time, messages, size_histogram=None):
 	if os.path.exists(filepath):
 		logging.debug("Not writing batch {} - already exists.".format(filename))
 	else:
-		temppath = "{}.{}.temp".format(filepath, uuid4())
-		ensure_directory(filepath)
-		with open(temppath, 'wb') as f:
-			f.write(output)
-		os.rename(temppath, filepath)
+		atomic_write(filepath, output)
 		logging.info("Wrote batch {}".format(filepath))
 	return filepath
 

chat_archiver/setup.py

@@ -11,5 +11,6 @@ setup(
 		'argh',
 		'gevent',
 		'monotonic',
+		'requests', # for emote fetching
 	],
 )