kes: flush audit log events to clients

This commit fixes a bug in the KES audit log API.
The server should flush any audit log event to its
clients directly. Otherwise, clients may not see
audit events since they may get buffered.

Signed-off-by: Andreas Auernhammer <[email protected]>

server.go

@@ -27,6 +27,7 @@ import (
 	"github.com/minio/kes/internal/cpu"
 	"github.com/minio/kes/internal/fips"
 	"github.com/minio/kes/internal/headers"
+	"github.com/minio/kes/internal/https"
 	"github.com/minio/kes/internal/key"
 	"github.com/minio/kes/internal/keystore"
 	"github.com/minio/kes/internal/metric"
@@ -1071,9 +1072,10 @@ func (s *Server) logAudit(resp *api.Response, req *api.Request) {
 	resp.Header().Set(headers.ContentType, headers.ContentTypeJSONLines)
 	resp.WriteHeader(http.StatusOK)
 
+	w := https.FlushOnWrite(resp.ResponseWriter)
 	auditLog := s.state.Load().Audit
-	auditLog.out.Add(resp.ResponseWriter)
-	defer auditLog.out.Remove(resp.ResponseWriter)
+	auditLog.out.Add(w)
+	defer auditLog.out.Remove(w)
 
 	<-req.Context().Done()
 }