From 8a50ebb8b71ba24b6da45031f28cb5d5be9ba963 Mon Sep 17 00:00:00 2001
From: Andrew Havens <email@andrewhavens.com>
Date: Fri, 31 Mar 2017 16:32:01 -0700
Subject: [PATCH 1/3] Rescue from connection refused errors and return the
 appropriate status code

---
 lib/rack_reverse_proxy/roundtrip.rb | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/lib/rack_reverse_proxy/roundtrip.rb b/lib/rack_reverse_proxy/roundtrip.rb
index 75cb350..a7d40e8 100644
--- a/lib/rack_reverse_proxy/roundtrip.rb
+++ b/lib/rack_reverse_proxy/roundtrip.rb
@@ -168,6 +168,9 @@ def rack_response_headers
           format_headers(target_response.headers)
         )
       )
+    rescue Errno::ECONNREFUSED => e
+      @_target_response = Struct.new(:status, :body).new(502, [])
+      {}
     end
 
     def replace_location_header

From beaecabd9c83b4778652fe3c000b1a0554f7e8ce Mon Sep 17 00:00:00 2001
From: John Bachir <j@jjb.cc>
Date: Wed, 7 Feb 2018 15:08:44 -0500
Subject: [PATCH 2/3] log to STDOUT when rescuing error from origin

---
 lib/rack_reverse_proxy/roundtrip.rb | 1 +
 1 file changed, 1 insertion(+)

diff --git a/lib/rack_reverse_proxy/roundtrip.rb b/lib/rack_reverse_proxy/roundtrip.rb
index a7d40e8..df0eb4c 100644
--- a/lib/rack_reverse_proxy/roundtrip.rb
+++ b/lib/rack_reverse_proxy/roundtrip.rb
@@ -169,6 +169,7 @@ def rack_response_headers
         )
       )
     rescue Errno::ECONNREFUSED => e
+      puts "rack-reverse-proxy rescued error from origin: #{e.class.name}: #{e.message}"
       @_target_response = Struct.new(:status, :body).new(502, [])
       {}
     end

From a25c50c2d7c95e8978b56d8b244cd8a71e28d2c0 Mon Sep 17 00:00:00 2001
From: John Bachir <j@jjb.cc>
Date: Wed, 7 Feb 2018 15:14:30 -0500
Subject: [PATCH 3/3] expand list of rescued origin request exceptions

list and methodology taken from

  https://github.com/lostisland/faraday/blob/master/lib/faraday/adapter/net_http.rb
---
 lib/rack_reverse_proxy/roundtrip.rb | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/lib/rack_reverse_proxy/roundtrip.rb b/lib/rack_reverse_proxy/roundtrip.rb
index df0eb4c..fd48c49 100644
--- a/lib/rack_reverse_proxy/roundtrip.rb
+++ b/lib/rack_reverse_proxy/roundtrip.rb
@@ -162,13 +162,31 @@ def build_response_headers
       end
     end
 
+    NET_HTTP_EXCEPTIONS = [
+      IOError,
+      Errno::ECONNABORTED,
+      Errno::ECONNREFUSED,
+      Errno::ECONNRESET,
+      Errno::EHOSTUNREACH,
+      Errno::EINVAL,
+      Errno::ENETUNREACH,
+      Errno::EPIPE,
+      Net::HTTPBadResponse,
+      Net::HTTPHeaderSyntaxError,
+      Net::ProtocolError,
+      SocketError,
+      Zlib::GzipFile::Error,
+    ]
+    NET_HTTP_EXCEPTIONS << OpenSSL::SSL::SSLError if defined?(OpenSSL)
+    NET_HTTP_EXCEPTIONS << Net::OpenTimeout if defined?(Net::OpenTimeout)
+
     def rack_response_headers
       Rack::Utils::HeaderHash.new(
         Rack::Proxy.normalize_headers(
           format_headers(target_response.headers)
         )
       )
-    rescue Errno::ECONNREFUSED => e
+    rescue *NET_HTTP_EXCEPTIONS => e
       puts "rack-reverse-proxy rescued error from origin: #{e.class.name}: #{e.message}"
       @_target_response = Struct.new(:status, :body).new(502, [])
       {}