diff options
| author | Tom Burns <tom.burns@jadedpixel.com> | 2012-10-30 16:22:21 -0400 |
|---|---|---|
| committer | Eric Wong <normalperson@yhbt.net> | 2012-11-29 20:24:46 +0000 |
| commit | 5c700fc2cf398848ddcf71a2aa3f0f2a6563e87b (patch) | |
| tree | 35757c61400f578092de06e813e044cf9b24abd9 /lib/unicorn/http_request.rb | |
| parent | f4af812a28b03508c96853739aea53f7a6714abf (diff) | |
| download | unicorn-5c700fc2cf398848ddcf71a2aa3f0f2a6563e87b.tar.gz | |
This patch checks incoming connections and avoids calling the application if the connection has been closed. It works by sending the beginning of the HTTP response before calling the application to see if the socket can successfully be written to. By enabling this feature users can avoid wasting application rendering time only to find the connection is closed when attempting to write, and throwing out the result. When a client disconnects while being queued or processed, Nginx will log HTTP response 499 but the application will log a 200. Enabling this feature will minimize the time window during which the problem can arise. The feature is disabled by default and can be enabled by adding 'check_client_connection true' to the unicorn config. [ew: After testing this change, Tom Burns wrote: So we just finished the US Black Friday / Cyber Monday weekend running unicorn forked with the last version of the patch I had sent you. It worked splendidly and helped us handle huge flash sales without increased response time over the weekend. Whereas in previous flash traffic scenarios we would see the number of HTTP 499 responses grow past the number of real HTTP 200 responses, over the weekend we saw no growth in 499s during flash sales. Unexpectedly the patch also helped us ward off a DoS attack where the attackers were disconnecting immediately after making a request. ref: <CAK4qKG3rkfVYLyeqEqQyuNEh_nZ8yw0X_cwTxJfJ+TOU+y8F+w@mail.gmail.com> ] Signed-off-by: Eric Wong <normalperson@yhbt.net>
Diffstat (limited to 'lib/unicorn/http_request.rb')
| -rw-r--r-- | lib/unicorn/http_request.rb | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/lib/unicorn/http_request.rb b/lib/unicorn/http_request.rb index a0435d6..79ead2e 100644 --- a/lib/unicorn/http_request.rb +++ b/lib/unicorn/http_request.rb @@ -22,11 +22,14 @@ class Unicorn::HttpParser NULL_IO = StringIO.new("") + attr_accessor :response_start_sent + # :stopdoc: # A frozen format for this is about 15% faster REMOTE_ADDR = 'REMOTE_ADDR'.freeze RACK_INPUT = 'rack.input'.freeze @@input_class = Unicorn::TeeInput + @@check_client_connection = false def self.input_class @@input_class @@ -35,6 +38,15 @@ class Unicorn::HttpParser def self.input_class=(klass) @@input_class = klass end + + def self.check_client_connection + @@check_client_connection + end + + def self.check_client_connection=(bool) + @@check_client_connection = bool + end + # :startdoc: # Does the majority of the IO processing. It has been written in @@ -70,6 +82,13 @@ class Unicorn::HttpParser # an Exception thrown from the parser will throw us out of the loop false until add_parse(socket.kgio_read!(16384)) end + + # detect if the socket is valid by writing a partial response: + if @@check_client_connection && headers? + @response_start_sent = true + Unicorn::Const::HTTP_RESPONSE_START.each { |c| socket.write(c) } + end + e[RACK_INPUT] = 0 == content_length ? NULL_IO : @@input_class.new(socket, self) e.merge!(DEFAULTS) |