Ensure leader resignation on shutdown (#3790)

To ensure proper leadership resignation during shutdown, an independent
context is created for election.Close, preventing failure due to the
canceled parent context.

Signed-off-by: Tomas Turek <tturek@redhat.com>

Author: osmman

CHANGELOG.md

@@ -3,6 +3,7 @@
 ## HEAD
 
 * Bump golangci-lint to v2.1.6
+* Fix leader resignation during a graceful shutdown by @osmman in https://github.com/google/trillian/pull/3790
 
 ## v1.7.2
 

util/election/runner.go

@@ -108,8 +108,10 @@ func (er *Runner) Run(ctx context.Context, pending chan<- Resignation) {
 
 	klog.V(1).Infof("%s: start election-monitoring loop ", er.id)
 	defer func() {
+		closeCtx, closeCancel := context.WithTimeout(context.Background(), time.Second)
+		defer closeCancel()
 		klog.Infof("%s: shutdown election-monitoring loop", er.id)
-		if err := er.election.Close(ctx); err != nil {
+		if err := er.election.Close(closeCtx); err != nil {
 			klog.Warningf("%s: election.Close: %v", er.id, err)
 		}
 	}()