From b49780e801e27adb4f3063686f3dde57ff6e2df3 Mon Sep 17 00:00:00 2001
From: Kazuki Yamaguchi <k@rhe.jp>
Date: Sun, 19 Apr 2015 12:10:03 +0900
Subject: worker_node/collector: implement heartbeat

---
 lib/collector/node_connection.rb        | 24 +++++++++++++++++++++---
 worker_node/lib/collector_connection.rb |  3 +++
 2 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/lib/collector/node_connection.rb b/lib/collector/node_connection.rb
index d12f567..3059577 100644
--- a/lib/collector/node_connection.rb
+++ b/lib/collector/node_connection.rb
@@ -1,3 +1,5 @@
+require "set"
+
 module Collector
   class NodeConnection < EM::Connection
     attr_reader :connection_id
@@ -6,15 +8,13 @@ module Collector
     @@_id = 0
 
     def initialize(queue)
-      # comm_inactivity_timeout exceed -> heatbeat -> (when alive) -> continue
-      #                                            -> (when not) -> unbind
-      self.comm_inactivity_timeout = 10
       @unpacker = MessagePack::Unpacker.new(symbolize_keys: true)
       @connection_id = (@@_id += 1)
       @authenticated = false
       @closing = false
       @activated_time = nil
       @queue = queue
+      @heartbeats = Set.new
     end
 
     def unbind
@@ -96,6 +96,9 @@ module Collector
         log(:info, "Closing this connection...")
         @closing = true
         NodeManager.unregister(self)
+      when "heartbeat"
+        log(:debug, "Heartbeat reply: #{msg[:data]}")
+        @heartbeats.delete(msg[:data])
       else
         log(:warn, "Unknown message: #{msg.inspect}")
         send_message(event: :error, data: "Unknown message.")
@@ -108,6 +111,7 @@ module Collector
         log(:info, "Connection authenticated.")
         send_message(event: :auth, data: nil)
         NodeManager.register(self)
+        @heartbeat_timer = EM.add_periodic_timer(10, &method(:heartbeat))
       else
         log(:warn, "Invalid secret_key: #{secret_key.inspect}")
         send_message(event: :error, data: "Invalid secret_key.")
@@ -120,6 +124,20 @@ module Collector
       send_data(data.to_msgpack)
     end
 
+    def heartbeat
+      if @heartbeats.size > 2 # 30 sec
+        log(:warn, "Node is dead.")
+        @heartbeat_timer.cancel
+        @closing = true
+        close_connection_after_writing
+        return
+      end
+
+      id = Time.now.to_i
+      @heartbeats << id
+      send_message(event: :heartbeat, data: id)
+    end
+
     def log(level, message)
       Rails.logger.__send__(level, "Node(#{@connection_id})") { message }
     end
diff --git a/worker_node/lib/collector_connection.rb b/worker_node/lib/collector_connection.rb
index e19383f..9a968f8 100644
--- a/worker_node/lib/collector_connection.rb
+++ b/worker_node/lib/collector_connection.rb
@@ -52,6 +52,9 @@ class CollectorConnection < EM::Connection
       register_account(msg[:data])
     when "unregister"
       unregister_account(msg[:data])
+    when "heartbeat"
+      log(:debug, "Heartbeat: #{msg[:data]}")
+      send_message(msg)
     else
       log(:warn, "Unknown message: #{msg.inspect}")
     end
-- 
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