don't log secrets even with debug logging enabled (#71)

secret/vault/vault.go

@@ -87,7 +87,7 @@ func (v *VaultSecrets) GetSecretsForTarget(name string) (map[string]string, erro
 	}
 
 	zap.L().Debug("found secrets in vault",
-		zap.Any("secret", secret))
+		zap.Strings("secret", keys(env)))
 
 	return env, nil
 }
@@ -152,6 +152,13 @@ func kvToMap(version int, data map[string]interface{}) (env map[string]string, e
 	return
 }
 
+func keys(m map[string]string) (k []string) {
+	for x := range m {
+		k = append(k, x)
+	}
+	return
+}
+
 // because Vault has no way to know if a kv engine is v1 or v2, we have to check
 // for the /config path and if it doesn't exist, attempt to LIST the path, if
 // that succeeds, it's a v1, if it doesn't succeed, it *might still* be a v1 but