Print container state when erroring that it is improper

This is a nice little convenience - lets people know why we won't
let them attach to a container.

Signed-off-by: Matthew Heon <mheon@redhat.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/pkg/api/handlers/compat/containers_attach.go b/pkg/api/handlers/compat/containers_attach.go
index 5fc3117b9..012e20daf 100644
--- a/pkg/api/handlers/compat/containers_attach.go
+++ b/pkg/api/handlers/compat/containers_attach.go
@@ -94,7 +94,7 @@ func AttachContainer(w http.ResponseWriter, r *http.Request) {
 			return
 		}
 	} else if !(state == define.ContainerStateCreated || state == define.ContainerStateRunning) {
-		utils.InternalServerError(w, errors.Wrapf(define.ErrCtrStateInvalid, "can only attach to created or running containers"))
+		utils.InternalServerError(w, errors.Wrapf(define.ErrCtrStateInvalid, "can only attach to created or running containers - currently in state %s", state.String()))
 		return
 	}