downloader: local provider source with symlinks

To work with a local recording from OBS, requires that the output format
is set to m3u8 + ts, and that the custom muxer settings includes
``hls_flags=+program_date_time``. ``hls_list_size=0`` will also ensure
that OBS provides the full playlist and appends new segments without
getting rid of old ones, which is useful for ensuring all segments are
downloaded

docker-compose.jsonnet

@@ -320,7 +320,8 @@
       ] + if $.downloader_creds_file != null then ["--twitch-auth-file", "/token"] else [],
       // Mount the segments directory at /mnt
       volumes: ["%s:/mnt" % $.segments_path]
-        + if $.downloader_creds_file != null then ["%s:/token" % $.downloader_creds_file] else [],
+        + if $.downloader_creds_file != null then ["%s:/token" % $.downloader_creds_file] else []
+        + if $.local_path != null then ["%s:/local" % $.local_path] else [],
       // If the application crashes, restart it.
       restart: "on-failure",
       // Expose on the configured host port by mapping that port to the default
@@ -534,7 +535,8 @@
         if $.nginx_serve_segments then "%s:/mnt" % $.segments_path,
         if $.ssl_certificate_path != null then "%s:/certs.pem" % $.ssl_certificate_path,
         if $.thrimbletrimmer_web_dev_path != null then "%s:/etc/nginx/html/thrimbletrimmer" % $.thrimbletrimmer_web_dev_path,
-      ]),
+      ])
+        + if $.local_path != null then ["%s:/local" % $.local_path] else [],
     },
 
     [if $.enabled.postgres then "postgres"]: {

downloader/downloader/main.py

@@ -21,7 +21,7 @@ import common
 import common.dateutil
 import common.requests
 
-from .providers import URLProvider, TwitchProvider, YoutubeProvider
+from .providers import URLProvider, TwitchProvider, YoutubeProvider, LocalProvider
 
 
 segments_downloaded = prom.Counter(
@@ -384,6 +384,15 @@ class StreamWorker(object):
 				if segment.uri not in self.getters:
 					if date is None:
 						raise ValueError("Cannot determine date of segment")
+					if isinstance(self.manager.provider, LocalProvider):
+						self.getters[segment.uri] = SegmentLinker(
+							self.logger,
+							self.manager.base_dir,
+							self.manager.channel,
+							segment,
+							date,
+						)
+					else:
 						self.getters[segment.uri] = SegmentGetter(
 							self.logger,
 							self.session,
@@ -649,6 +658,9 @@ def main(channels, base_dir=".", qualities="source", metrics_port=8001, backdoor
 		elif type == "youtube":
 			provider = YoutubeProvider(url)
 			channel_qualities = ["source"]
+		elif type == "local":
+			provider = LocalProvider(url)
+			channel_qualities = ["source"]
 		else:
 			raise ValueError(f"Unknown type {type!r}")
 		manager = StreamsManager(provider, channel, base_dir, channel_qualities, important=important)
@@ -687,3 +699,50 @@ def main(channels, base_dir=".", qualities="source", metrics_port=8001, backdoor
 		worker.get() # re-raise error if failed
 
 	logging.info("Gracefully stopped")
+
+class SegmentLinker(SegmentGetter):
+	def __init__(self, parent_logger, base_dir, channel, segment, date):
+		self.logger = parent_logger.getChild("SegmentLinker@{:x}".format(id(self)))
+		self.base_dir = base_dir
+		self.channel = channel
+		self.segment = segment
+		self.date = date
+		self.prefix = self.make_path_prefix()
+		self.retry = None
+		self.done = gevent.event.Event()
+		# Our parent's connection pool, but we'll replace it if there's any issues
+
+	def make_path_prefix(self):
+		return os.path.join(
+			self.base_dir,
+			'local',
+			'source',
+			self.date.strftime("%Y-%m-%dT%H"),
+			"{date}-{duration}".format(
+				date=self.date.strftime("%M:%S.%f"),
+				duration=self.segment.duration,
+			),
+		)
+
+	def make_path(self, hash=None):
+		"""Generate filepath for the segment.
+		"""
+		arg = b64encode(hash.digest(), b"-_").decode().rstrip("=") if hash else str(uuid.uuid4())
+		return "{}-full-{}.ts".format(self.prefix, arg)
+
+	def _get_segment(self):
+		hash = hashlib.sha256()
+		with open(self.segment.uri, 'rb') as f:
+			while chunk := f.read(8192):
+				hash.update(chunk)
+
+		dest_path = self.make_path(hash)
+		common.ensure_directory(dest_path)
+		self.logger.debug("Linking segment: {} to {}".format(dest_path, self.segment.uri))
+		os.symlink(self.segment.uri, dest_path)
+
+		segments_downloaded.labels(type="full", channel=self.channel, quality="source").inc()
+		segment_duration_downloaded.labels(type="full", channel=self.channel, quality="source").inc(self.segment.duration)
+		stat = latest_segment.labels(channel=self.channel, quality="source")
+		timestamp = (self.date - datetime.datetime(1970, 1, 1)).total_seconds()
+		stat.set(max(stat._value.get(), timestamp))

downloader/downloader/providers.py

@@ -3,6 +3,7 @@ import json
 import logging
 import random
 import subprocess
+import os
 
 from common.requests import InstrumentedSession
 
@@ -195,3 +196,26 @@ class TwitchProvider(Provider):
 		variants["source"] = source
 
 		return {name: variant.uri for name, variant in variants.items()}
+
+class LocalProvider(Provider):
+	"""Provider that uses a local m3u8 recording.
+	"""
+	def __init__(self, directory):
+		self.directory = directory
+
+	def get_media_playlist(self, uri, session=None):
+		with open(uri) as f:
+			playlist = hls_playlist.load(f.read().strip(), uri)
+		return playlist
+
+	def get_media_playlist_uris(self, qualities, session=None):
+		if qualities != ["source"]:
+			raise ValueError("Cannot provide non-source qualities")
+
+		files = os.listdir(self.directory)
+
+		for file in reversed(files):
+			if file.endswith(".m3u8"):
+				return {"source": os.path.join(self.directory, file)}
+
+		raise ValueError("Can't find playlist (m3u8) file")