From 3f8107114379df8fdbbf5b3ac5333ffb0af32a38 Mon Sep 17 00:00:00 2001
From: Amber Brown <ambrown@redhat.com>
Date: Mon, 31 Oct 2022 15:19:50 +1100
Subject: [PATCH] enable copy.Image's optimisation for cases where the
 destination image already exists (#2501)

---
 pkg/mirror/mirror.go | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/pkg/mirror/mirror.go b/pkg/mirror/mirror.go
index 3daa5890f..11e80ae80 100644
--- a/pkg/mirror/mirror.go
+++ b/pkg/mirror/mirror.go
@@ -45,6 +45,11 @@ func Copy(ctx context.Context, dstreference, srcreference string, dstauth, srcau
 		DestinationCtx: &types.SystemContext{
 			DockerAuthConfig: dstauth,
 		},
+		// Images that we mirror shouldn't change, so we can use the
+		// optimisation that checks if the source and destination manifests are
+		// equal before attempting to push it (and sending no blobs because
+		// they're all already there)
+		OptimizeDestinationImageAlreadyExists: true,
 	})
 
 	return err