Implement /keys/changes (#1232)

* Implement /keys/changes

And refactor QueryKeyChanges to accept a `to` offset.

* Unbreak tests

* Sort keys when serialising log tokens

1 files changed, 3 insertions, 0 deletions

diff --git a/keyserver/api/api.go b/keyserver/api/api.go
index c9afb09c..98bcd944 100644
--- a/keyserver/api/api.go
+++ b/keyserver/api/api.go
@@ -138,6 +138,9 @@ type QueryKeyChangesRequest struct {
 	Partition int32
 	// The offset of the last received key event, or sarama.OffsetOldest if this is from the beginning
 	Offset int64
+	// The inclusive offset where to track key changes up to. Messages with this offset are included in the response.
+	// Use sarama.OffsetNewest if the offset is unknown (then check the response Offset to avoid racing).
+	ToOffset int64
 }
 
 type QueryKeyChangesResponse struct {