raise Unicorn::ClientShutdown if client aborts in TeeInput

Leaving the EOFError exception as-is bad because most
applications/frameworks run an application-wide exception
handler to pretty-print and/or log the exception with a huge
backtrace.

Since there's absolutely nothing we can do in the server-side
app to deal with clients prematurely shutting down, having a
backtrace does not make sense.  Having a backtrace can even be
harmful since it creates unnecessary noise for application
engineers monitoring or tracking down real bugs.

2 files changed, 17 insertions, 0 deletions

diff --git a/lib/unicorn.rb b/lib/unicorn.rb
index a696402..c6c311e 100644
--- a/lib/unicorn.rb
+++ b/lib/unicorn.rb
@@ -8,6 +8,12 @@ autoload :Rack, 'rack'
 # a Unicorn web server.  It contains a minimalist HTTP server with just enough
 # functionality to service web application requests fast as possible.
 module Unicorn
+
+  # raise this inside TeeInput when a client disconnects inside the
+  # application dispatch
+  class ClientShutdown < EOFError
+  end
+
   autoload :Const, 'unicorn/const'
   autoload :HttpRequest, 'unicorn/http_request'
   autoload :HttpResponse, 'unicorn/http_response'
diff --git a/lib/unicorn/tee_input.rb b/lib/unicorn/tee_input.rb
index 69397c0..50ddb5b 100644
--- a/lib/unicorn/tee_input.rb
+++ b/lib/unicorn/tee_input.rb
@@ -135,10 +135,21 @@ module Unicorn
         end
       end
       finalize_input
+      rescue EOFError
+        # in case client only did a premature shutdown(SHUT_WR)
+        # we do support clients that shutdown(SHUT_WR) after the
+        # _entire_ request has been sent, and those will not have
+        # raised EOFError on us.
+        socket.close if socket
+        raise ClientShutdown, "bytes_read=#{@tmp.size}", []
     end
 
     def finalize_input
       while parser.trailers(req, buf).nil?
+        # Don't worry about throw-ing :http_499 here on EOFError, tee()
+        # will catch EOFError when app is processing it, otherwise in
+        # initialize we never get any chance to enter the app so the
+        # EOFError will just get trapped by Unicorn and not the Rack app
         buf << socket.readpartial(Const::CHUNK_SIZE)
       end
       self.socket = nil