Raise custom auth error, re-raise on failed re-auth

app/controllers/services/lightning_controller.rb

@@ -49,9 +49,9 @@ class Services::LightningController < ApplicationController
     lndhub = Lndhub.new
     data = lndhub.balance @ln_auth_token
     @balance = data["BTC"]["AvailableBalance"] rescue nil
-  rescue
+  rescue AuthError
     authenticate_with_lndhub(force_reauth: true)
-    return nil if @fetch_balance_retried
+    raise if @fetch_balance_retried
     @fetch_balance_retried = true
     fetch_balance
   end
@@ -61,9 +61,9 @@ class Services::LightningController < ApplicationController
     txs = lndhub.gettxs @ln_auth_token
     invoices = lndhub.getuserinvoices(@ln_auth_token).select{|i| i["ispaid"]}
     process_transactions(txs + invoices)
-  rescue
+  rescue AuthError
     authenticate_with_lndhub(force_reauth: true)
-    return [] if @fetch_transactions_retried
+    raise if @fetch_transactions_retried
     @fetch_transactions_retried = true
     fetch_transactions
   end

app/errors/auth_error.rb

@@ -0,0 +1 @@
+class AuthError < StandardError; end

app/services/lndhub.rb

@@ -26,7 +26,7 @@ class Lndhub
     data = JSON.parse(res.body)
 
     if data.is_a?(Hash) && data["error"] && data["message"] == "bad auth"
-      raise "BAD_AUTH"
+      raise AuthError
     else
       data
     end