Added support for TCP octet-counting framing

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 3.8.0
+  - Added support for transparent framing / octet-counting. See [RFC 6587 section 3.4.1](https://www.ietf.org/rfc/rfc6587.txt)
+
 ## 3.7.1
   - Fix issue where the priority field was not being set correctly when grok failed [#76](https://github.com/logstash-plugins/logstash-input-syslog/pull/78)
 

docs/index.asciidoc

@@ -33,8 +33,9 @@ supports `RFC3164` syslog with some small modifications. However, some
 non-standard syslog formats can be read and parsed if a functional
 `grok_pattern` is provided. The date format is still only allowed to be
 `RFC3164` style or `ISO8601`.
+This input supports UDP and TCP. Both TCP transparent and non-transparent framming are supported.
 
-For more information see the http://www.ietf.org/rfc/rfc3164.txt[RFC3164 page].
+For more information on syslog see the http://www.ietf.org/rfc/rfc3164.txt[RFC3164 page] and for more information on TCP framing see the https://www.ietf.org/rfc/rfc6587.txt[RFC 6587 page].
 
 Note: This input will start listeners on both TCP and UDP.
 

lib/logstash/inputs/syslog.rb

@@ -227,16 +227,40 @@ def tcp_read_lines(socket)
     buffer = String.new
     loop do
       begin
-        buffer << socket.read_nonblock(1024)
-        while (newline = buffer.index("\n"))
-          yield buffer.slice!(0..newline)
-        end
+        buffer << socket.read_nonblock(1)
+        break if  buffer.length >= 1
       rescue IO::WaitReadable
         IO.select([socket], nil)
         retry
       end
     end
-  end
+    if buffer[0].match?(/\d/) #Check if the first char is a digit
+      loop do
+        begin
+          buffer << socket.read_nonblock(16)
+          first_space = buffer.index(" ")
+          log_len = Integer(buffer.slice!(0..first_space))
+          buffer << socket.read_nonblock(log_len-buffer.length)
+          yield buffer.slice!(0..log_len)
+        rescue IO::WaitReadable
+          IO.select([socket], nil)
+          retry
+        end
+      end
+    else
+      loop do
+        begin
+          buffer << socket.read_nonblock(1024)
+          while (newline = buffer.index("\n"))
+            yield buffer.slice!(0..newline)
+          end
+        rescue IO::WaitReadable
+          IO.select([socket], nil)
+          retry
+        end
+      end
+    end
+  end 
 
   # tcp_receiver is executed in a thread, any uncatched exception will be bubbled up to the
   # tcp server thread and all tcp connections will be closed and the listener restarted.

version

@@ -1 +1 @@
-3.7.1
+3.8.0