Use FieldSelector to select only tls secrets (#82)

This speeds up the listing of certs significatnyly in clusters with many secrets.

prober/kubernetes.go

@@ -44,23 +44,21 @@ func probeKubernetes(ctx context.Context, target string, module config.Module, r
  name := parts[1]
 
  var tlsSecrets []v1.Secret
- secrets, err := client.CoreV1().Secrets("").List(ctx, metav1.ListOptions{})
+ secrets, err := client.CoreV1().Secrets("").List(ctx, metav1.ListOptions{FieldSelector: "type=kubernetes.io/tls"})
  if err != nil {
  return err
  }
  for _, secret := range secrets.Items {
- if secret.Type == "kubernetes.io/tls" {
- nMatch, err := doublestar.Match(ns, secret.Namespace)
- if err != nil {
- return err
- }
- sMatch, err := doublestar.Match(name, secret.Name)
- if err != nil {
- return err
- }
- if nMatch && sMatch {
- tlsSecrets = append(tlsSecrets, secret)
- }
+ nMatch, err := doublestar.Match(ns, secret.Namespace)
+ if err != nil {
+ return err
+ }
+ sMatch, err := doublestar.Match(name, secret.Name)
+ if err != nil {
+ return err
+ }
+ if nMatch && sMatch {
+ tlsSecrets = append(tlsSecrets, secret)
  }
  }