sarapprover: ignore authz errors

pkg/controller/certificates/certificate_controller.go

@@ -135,7 +135,11 @@ func (cc *CertificateController) processNextWorkItem() bool {
 
 	if err := cc.syncFunc(cKey.(string)); err != nil {
 		cc.queue.AddRateLimited(cKey)
-		utilruntime.HandleError(fmt.Errorf("Sync %v failed with : %v", cKey, err))
+		if _, ignorable := err.(ignorableError); !ignorable {
+			utilruntime.HandleError(fmt.Errorf("Sync %v failed with : %v", cKey, err))
+		} else {
+			glog.V(4).Infof("Sync %v failed with : %v", cKey, err)
+		}
 		return true
 	}
 
@@ -181,3 +185,17 @@ func (cc *CertificateController) syncFunc(key string) error {
 
 	return cc.handler(csr)
 }
+
+// IgnorableError returns an error that we shouldn't handle (i.e. log) because
+// it's spammy and usually user error. Instead we will log these errors at a
+// higher log level. We still need to throw these errors to signal that the
+// sync should be retried.
+func IgnorableError(s string, args ...interface{}) ignorableError {
+	return ignorableError(fmt.Sprintf(s, args...))
+}
+
+type ignorableError string
+
+func (e ignorableError) Error() string {
+	return string(e)
+}