extras/proxy_pass: log exceptions leading to 502

It may be useful for us to track down potential errors in
our code or log when an upstream misbehaves.

1 files changed, 4 insertions, 0 deletions

diff --git a/extras/proxy_pass.rb b/extras/proxy_pass.rb
index 8a32cac..de6a2b1 100644
--- a/extras/proxy_pass.rb
+++ b/extras/proxy_pass.rb
@@ -189,6 +189,10 @@ class ProxyPass # :nodoc:
     res
   rescue => e
     retry if ures && ures.fail_retryable? && request_method != "POST"
+    if defined?(Yahns::Log)
+      logger = env['rack.logger'] and
+        Yahns::Log.exception(logger, 'proxy_pass', e)
+    end
     ERROR_502
   end