add idle_timeout between log messages for a given tag

Author: zarqman

CHANGELOG.md

@@ -2,6 +2,7 @@
 
 * Renamed `cert` and `key` to `client_cert` and `client_key` respectively.
 * Change to short timeouts on network calls so logging doesn't go dead for extended periods.
+* Added `idle_timeout` to force upstream reconnection after a period of time with no traffic for a particular tag. Useful for low-traffic senders. Not recommended for high-traffic.
 
 
 #### 1.0.0

docs/configuration.md

@@ -15,6 +15,10 @@ Host represents DNS name of endpoint where should be data sent. Example: `syslog
 
 Example: `6514`
 
+### idle_timeout
+
+If a given tag has gone this many seconds between log messages, disconnect and reconnect before sending logs. Useful in low-traffic logging situations with remote hosts that disconnect after a period of time. Disabled by default. Example: `600`
+
 ### token
 
 Some services require a token to identify the account. Example: `ABABABABABABA@99999`. Not required for Papertrail.
@@ -72,6 +76,7 @@ Optionally record key where to get msgid from the record. If not provided nil va
   @type syslog_tls
   host logs1.papertrailapp.com
   port 12345
+  idle_timeout 720
 
   hostname static-hostname
   facility SYSLOG

lib/fluent/plugin/out_syslog_tls.rb

@@ -29,6 +29,7 @@ class SyslogTlsOutput < Fluent::Output
 
     config_param :host, :string
     config_param :port, :integer
+    config_param :idle_timeout, :integer, default: nil
     config_param :token, :string, default: nil
     config_param :client_cert, :string, default: nil
     config_param :client_key, :string, default: nil
@@ -99,7 +100,7 @@ def logger(tag)
     end
 
     def new_logger(tag)
-      transport = ::SyslogTls::SSLTransport.new(host, port, client_cert: client_cert, client_key: client_key, max_retries: 3)
+      transport = ::SyslogTls::SSLTransport.new(host, port, idle_timeout: idle_timeout, client_cert: client_cert, client_key: client_key, max_retries: 3)
       logger = ::SyslogTls::Logger.new(transport, token)
       logger.facility(facility)
       logger.hostname(hostname)

lib/syslog_tls/ssl_transport.rb

@@ -25,13 +25,14 @@ class SSLTransport
 
     attr_accessor :socket
 
-    attr_reader :host, :port, :client_cert, :client_key, :ssl_version
+    attr_reader :host, :port, :idle_timeout, :client_cert, :client_key, :ssl_version
 
     attr_writer :retries
 
-    def initialize(host, port, client_cert: nil, client_key: nil, ssl_version: :TLSv1_2, max_retries: 1)
+    def initialize(host, port, idle_timeout: nil, client_cert: nil, client_key: nil, ssl_version: :TLSv1_2, max_retries: 1)
       @host = host
       @port = port
+      @idle_timeout = idle_timeout
       @client_cert = client_cert
       @client_key = client_key
       @ssl_version = ssl_version
@@ -52,6 +53,7 @@ def connect
       rescue Errno::ETIMEDOUT
         raise 'Socket timeout during connect'
       end
+      @last_write = Time.now if idle_timeout
     end
 
     def get_tcp_connection
@@ -103,6 +105,14 @@ def get_ssl_connection
 
     # Allow to retry on failed writes
     def write(s)
+      if idle_timeout
+        if (t=Time.now) > @last_write + idle_timeout
+          @socket.close rescue nil
+          connect
+        else
+          @last_write = t
+        end
+      end
       begin
         retry_id ||= 0
         do_write(s)