diff --git a/docker/matrix-eavesdrop/src/eavesdrop/bot.py b/docker/matrix-eavesdrop/src/eavesdrop/bot.py
index 2e7622d1a4..01e7a16e85 100644
--- a/docker/matrix-eavesdrop/src/eavesdrop/bot.py
+++ b/docker/matrix-eavesdrop/src/eavesdrop/bot.py
@@ -94,6 +94,12 @@ class Bot:
                 data = json.load(f)
                 return data
 
+    def get_room_path(self, room):
+        room_path = room['path']
+        if not room_path.startswith('/'):
+            room_path = os.path.join(self.config['log_dir'], room_path)
+        return room_path
+
     async def join_rooms(self):
         new = set()
         old = set()
@@ -107,7 +113,7 @@ class Bot:
             # Store the canonical room id, since the one in the config
             # file may be an alias
             self.room_map[resp.room_id] = room
-            os.makedirs(room['path'], exist_ok=True)
+            os.makedirs(self.get_room_path(room), exist_ok=True)
         for room in old-new:
             self.log.info("Leave room %s", room['id'])
             await self.client.room_leave(room)
@@ -120,9 +126,7 @@ class Bot:
         ts = datetime.datetime.utcfromtimestamp(event.server_timestamp/1000.0)
         event_date = str(ts.date())
         event_time = str(ts.time())[:8]
-        room_path = config_room['path']
-        if not room_path.startswith('/'):
-            room_path = os.path.join(self.config['log_dir'], room_path)
+        room_path = self.get_room_path(config_room)
         filename = f'{room_name}.{event_date}.log'
         logpath = os.path.join(room_path, filename)
         body = event.body