Add basic cache expiry for .osu files

app/usecases/osu_files.py

@@ -1,31 +1,57 @@
+import hashlib
 import logging
 
 from app.adapters import aws_s3
 from app.adapters import osu_api_v1
+from app.repositories import akatsuki_beatmaps
+
+
+def hash_content(content: bytes) -> str:
+    return hashlib.md5(content).hexdigest()
+
+
+async def _osu_file_cache_expired(
+    *,
+    beatmap_id: int,
+    beatmap_osu_file_data: bytes,
+) -> bool:
+    akatsuki_beatmap = await akatsuki_beatmaps.fetch_one_by_id(beatmap_id)
+    return (
+        akatsuki_beatmap is None
+        or hash_content(beatmap_osu_file_data) != akatsuki_beatmap.beatmap_md5
+    )
 
 
 async def fetch_beatmap_osu_file_data(beatmap_id: int) -> bytes | None:
     beatmap_osu_file_data = await aws_s3.get_object_data(f"/beatmaps/{beatmap_id}.osu")
-    if beatmap_osu_file_data is None:
-        beatmap_osu_file_data = await osu_api_v1.fetch_beatmap_osu_file_data(beatmap_id)
-        if beatmap_osu_file_data is None:
-            return None
+    if beatmap_osu_file_data is not None:
+        if not await _osu_file_cache_expired(
+            beatmap_id=beatmap_id,
+            beatmap_osu_file_data=beatmap_osu_file_data,
+        ):
+            return beatmap_osu_file_data
 
-        await aws_s3.save_object_data(
-            f"/beatmaps/{beatmap_id}.osu",
-            beatmap_osu_file_data,
-        )
         logging.info(
-            "Saved beatmap osu file to s3",
+            "Updating expired beatmap s3 osu file cache",
             extra={"beatmap_id": beatmap_id},
         )
-        # NOTE: this is a place where .osu files could become desynced
-        #       with akatsuki beatmaps in the mysql database, however we've
-        #       decided to not worry about this for now, as most use cases
-        #       which rely on .osu files will also fetch the beatmap metadata,
-        #       forcing an update to occur.
-    else:
-        # TODO: consider cache expiry
-        ...
+
+    beatmap_osu_file_data = await osu_api_v1.fetch_beatmap_osu_file_data(beatmap_id)
+    if beatmap_osu_file_data is None:
+        return None
+
+    await aws_s3.save_object_data(
+        f"/beatmaps/{beatmap_id}.osu",
+        beatmap_osu_file_data,
+    )
+    logging.info(
+        "Saved beatmap osu file to s3",
+        extra={"beatmap_id": beatmap_id},
+    )
+    # NOTE: this is a place where .osu files could become desynced
+    #       with akatsuki beatmaps in the mysql database, however we've
+    #       decided to not worry about this for now, as most use cases
+    #       which rely on .osu files will also fetch the beatmap metadata,
+    #       forcing an update to occur.
 
     return beatmap_osu_file_data