Make search expansion grow through time instead of shrink (#448)

* Make expansion grow through time instead of shrink

* Use list evaluation, primarily to re-trigger travis build

* Add config parameters for search expansion

* Adjust default config values

server/config.py

@@ -58,3 +58,6 @@
 CONTROL_SERVER_PORT = int(os.getenv('CONTROL_SERVER_PORT', 4000))
 
 LADDER_ANTI_REPETITION_LIMIT = int(os.getenv('LADDER_ANTI_REPETITION_LIMIT', 3))
+LADDER_SEARCH_EXPANSION_START = int(os.getenv('LADDER_SEARCH_EXPANSION_START', 60 * 2))
+LADDER_SEARCH_EXPANSION_END = int(os.getenv('LADDER_SEARCH_EXPANSION_END', 60 * 20))
+LADDER_SEARCH_EXPANSION_MAX = float(os.getenv('LADDER_SEARCH_EXPANSION_MAX', 0.25))

server/lobbyconnection.py

@@ -637,7 +637,7 @@ async def command_avatar(self, message):
                     avatar = {"url": row["url"], "tooltip": row["tooltip"]}
                     avatarList.append(avatar)
 
-                if len(avatarList) > 0:
+                if avatarList:
                     self.sendJSON({"command": "avatar", "avatarlist": avatarList})
 
         elif action == "select":

server/matchmaker/search.py

@@ -3,11 +3,12 @@
 import time
 from typing import List, Optional
 
-import server.config as config
-from server.decorators import with_logger
-from server.players import Player
 from trueskill import Rating, quality
 
+from .. import config
+from ..decorators import with_logger
+from ..players import Player
+
 
 @with_logger
 class Search():
@@ -97,14 +98,34 @@ def boundary_75(self):
         return rounded_mu - 100, rounded_mu + 100
 
     @property
-    def search_expansion(self):
+    def search_expansion(self) -> float:
         """
-        Defines how much to expand the search range of game quality due to waiting time
+        Defines how much to expand the search range of game quality due to waiting
+        time.
+
+        The graph of this function over time looks essentially like this:
+                           END (x)-> ___ <- MAX (y)
+                                    /
+                                ___/ <- START (x)
+        The search threshold will not expand until a certain time START has been
+        reached. Then it will expand linearly with time until time END, at which
+        point it will have reached it's maximum value and will not expand
+        further.
         """
-        return 0.25 * min(1 / ((time.time() - self.start_time) / 300), 1)
+        elapsed = time.time() - self.start_time
+        MAX = config.LADDER_SEARCH_EXPANSION_MAX
+        START = config.LADDER_SEARCH_EXPANSION_START
+        END = config.LADDER_SEARCH_EXPANSION_END
+
+        if elapsed < START:
+            return 0.0
+        if elapsed > END:
+            return MAX
+
+        return (MAX / (END - START)) * (elapsed - START)
 
     @property
-    def match_threshold(self):
+    def match_threshold(self) -> float:
         """
         Defines the threshold for game quality
 
@@ -119,7 +140,7 @@ def match_threshold(self):
                     thresholds.append(max(q - self.search_expansion, 0))
         return min(thresholds)
 
-    def quality_with(self, other: 'Search'):
+    def quality_with(self, other: 'Search') -> float:
         assert all(other.raw_ratings)
         assert other.players
 

tests/unit_tests/test_matchmaker_queue.py

@@ -2,10 +2,10 @@
 import random
 from collections import deque
 from concurrent.futures import CancelledError, TimeoutError
-from unittest.mock import Mock
 
 import pytest
 import server.config as config
+from mock import Mock
 from server.matchmaker import MatchmakerQueue, Search
 from server.players import Player
 
@@ -89,14 +89,30 @@ def test_search_no_match_wrong_type(matchmaker_players):
 
 
 def test_search_boundaries(matchmaker_players):
-    p1, _, _, _, _, _ = matchmaker_players
+    p1 = matchmaker_players[0]
     s1 = Search([p1])
     assert p1.ladder_rating[0] > s1.boundary_80[0]
     assert p1.ladder_rating[0] < s1.boundary_80[1]
     assert p1.ladder_rating[0] > s1.boundary_75[0]
     assert p1.ladder_rating[0] < s1.boundary_75[1]
 
 
+def test_search_expansion(matchmaker_players, mocker):
+    p1 = matchmaker_players[0]
+    mocker.patch('time.time', return_value=0)
+    s1 = Search([p1])
+
+    assert s1.search_expansion == 0.0
+    mocker.patch('time.time', return_value=500)
+    assert s1.search_expansion > 0.0
+
+    # Make sure that the expansion stops at some point
+    mocker.patch('time.time', return_value=500_000)
+    e1 = s1.search_expansion
+    mocker.patch('time.time', return_value=500_300)
+    assert e1 == s1.search_expansion
+
+
 async def test_search_await(mocker, loop, matchmaker_players):
     p1, p2, _, _, _, _ = matchmaker_players
     s1, s2 = Search([p1]), Search([p2])