From 48af5921f9488838865b381a0dd464b70c449bbd Mon Sep 17 00:00:00 2001
From: reivilibre <oliverw@matrix.org>
Date: Fri, 7 Jun 2024 12:01:21 +0100
Subject: [PATCH] Add debug logging for when room keys are uploaded, including
 whether they are replacing other room keys. (#17266)

Fixes: #17013

Add logging for whether room keys are replaced
This is motivated by the Crypto team who need to diagnose crypto issues.

The existing opentracing logging is not enough because it is not enabled
for all users.
---
 changelog.d/17266.misc            |  1 +
 synapse/handlers/e2e_room_keys.py | 18 ++++++++++++++++++
 2 files changed, 19 insertions(+)
 create mode 100644 changelog.d/17266.misc

diff --git a/changelog.d/17266.misc b/changelog.d/17266.misc
new file mode 100644
index 00000000000..ce8c4ab0869
--- /dev/null
+++ b/changelog.d/17266.misc
@@ -0,0 +1 @@
+Add debug logging for when room keys are uploaded, including whether they are replacing other room keys.
\ No newline at end of file
diff --git a/synapse/handlers/e2e_room_keys.py b/synapse/handlers/e2e_room_keys.py
index e76a51ba308..99f9f6e64a7 100644
--- a/synapse/handlers/e2e_room_keys.py
+++ b/synapse/handlers/e2e_room_keys.py
@@ -247,6 +247,12 @@ async def upload_room_keys(
                     if current_room_key:
                         if self._should_replace_room_key(current_room_key, room_key):
                             log_kv({"message": "Replacing room key."})
+                            logger.debug(
+                                "Replacing room key. room=%s session=%s user=%s",
+                                room_id,
+                                session_id,
+                                user_id,
+                            )
                             # updates are done one at a time in the DB, so send
                             # updates right away rather than batching them up,
                             # like we do with the inserts
@@ -256,6 +262,12 @@ async def upload_room_keys(
                             changed = True
                         else:
                             log_kv({"message": "Not replacing room_key."})
+                            logger.debug(
+                                "Not replacing room key. room=%s session=%s user=%s",
+                                room_id,
+                                session_id,
+                                user_id,
+                            )
                     else:
                         log_kv(
                             {
@@ -265,6 +277,12 @@ async def upload_room_keys(
                             }
                         )
                         log_kv({"message": "Replacing room key."})
+                        logger.debug(
+                            "Inserting new room key. room=%s session=%s user=%s",
+                            room_id,
+                            session_id,
+                            user_id,
+                        )
                         to_insert.append((room_id, session_id, room_key))
                         changed = True