Extract app from torrent handling code

Fixes https://jira.coreos.com/browse/QUAY-969

util/registry/torrent.py

@@ -2,49 +2,52 @@ import hashlib
 import time
 
 from binascii import hexlify
-from cachetools import lru_cache
 
 import bencode
 import jwt
 import resumablehashlib
 
-from app import app, instance_keys
+
+class TorrentConfiguration(object):
+  def __init__(self, instance_keys, announce_url, filename_pepper, registry_title):
+    self.instance_keys = instance_keys
+    self.announce_url = announce_url
+    self.filename_pepper = filename_pepper
+    self.registry_title = registry_title
+
+  @classmethod
+  def for_testing(cls, instance_keys, announce_url, registry_title):
+    return TorrentConfiguration(instance_keys, announce_url, 'somepepper', registry_title)
+
+  @classmethod
+  def from_app_config(cls, instance_keys, config):
+    return TorrentConfiguration(instance_keys, config['BITTORRENT_ANNOUNCE_URL'],
+                                config['BITTORRENT_FILENAME_PEPPER'], config['REGISTRY_TITLE'])
 
 
-ANNOUNCE_URL = app.config['BITTORRENT_ANNOUNCE_URL']
-FILENAME_PEPPER = app.config['BITTORRENT_FILENAME_PEPPER']
-REGISTRY_TITLE = app.config['REGISTRY_TITLE']
-
-
-@lru_cache(maxsize=1)
-def _load_private_key(private_key_file_path):
-  with open(private_key_file_path) as private_key_file:
-    return private_key_file.read()
-
-
-def jwt_from_infodict(infodict):
+def _jwt_from_infodict(torrent_config, infodict):
   """ Returns an encoded JWT for the given BitTorrent info dict, signed by the local instance's
       private key.
   """
   digest = hashlib.sha1()
   digest.update(bencode.bencode(infodict))
-  return jwt_from_infohash(digest.digest())
+  return jwt_from_infohash(torrent_config, digest.digest())
 
 
-def jwt_from_infohash(infohash_digest):
+def jwt_from_infohash(torrent_config, infohash_digest):
   """ Returns an encoded JWT for the given BitTorrent infohash, signed by the local instance's
       private key.
   """
   token_data = {
-    'iss': instance_keys.service_name,
-    'aud': ANNOUNCE_URL,
+    'iss': torrent_config.instance_keys.service_name,
+    'aud': torrent_config.announce_url,
     'infohash': hexlify(infohash_digest),
   }
-  return jwt.encode(token_data, instance_keys.local_private_key, algorithm='RS256',
-                    headers={'kid': instance_keys.local_key_id})
+  return jwt.encode(token_data, torrent_config.instance_keys.local_private_key, algorithm='RS256',
+                    headers={'kid': torrent_config.instance_keys.local_key_id})
 
 
-def make_torrent(name, webseed, length, piece_length, pieces):
+def make_torrent(torrent_config, name, webseed, length, piece_length, pieces):
   info_dict = {
     'name': name,
     'length': length,
@@ -53,22 +56,26 @@ def make_torrent(name, webseed, length, piece_length, pieces):
     'private': 1,
   }
 
+  info_jwt = _jwt_from_infodict(torrent_config, info_dict)
   return bencode.bencode({
-    'announce': ANNOUNCE_URL + "?jwt=" + jwt_from_infodict(info_dict),
+    'announce': torrent_config.announce_url + "?jwt=" + info_jwt,
     'url-list': str(webseed),
     'encoding': 'UTF-8',
-    'created by': REGISTRY_TITLE,
+    'created by': torrent_config.registry_title,
     'creation date': int(time.time()),
     'info': info_dict,
   })
 
 
 def public_torrent_filename(blob_uuid):
+  """ Returns the filename for the given blob UUID in a public image. """
   return hashlib.sha256(blob_uuid).hexdigest()
 
 
-def per_user_torrent_filename(user_uuid, blob_uuid):
-  return hashlib.sha256(FILENAME_PEPPER + "||" + blob_uuid + "||" + user_uuid).hexdigest()
+def per_user_torrent_filename(torrent_config, user_uuid, blob_uuid):
+  """ Returns the filename for the given blob UUID for a private image. """
+  joined = torrent_config.filename_pepper + "||" + blob_uuid + "||" + user_uuid
+  return hashlib.sha256(joined).hexdigest()
 
 
 class PieceHasher(object):