agent.rb in instana-1.7.1

- old
+ new

@@ -2,17 +2,20 @@
 require 'net/http'
 require 'socket'
 require 'sys/proctable'
 require 'timers'
 require 'uri'
+require 'thread'
 include Sys
 
 module Instana
   class Agent
     attr_accessor :state
     attr_accessor :agent_uuid
     attr_accessor :process
+    attr_accessor :collect_thread
+    attr_accessor :thread_spawn_lock
 
     LOCALHOST = '127.0.0.1'.freeze
     MIME_JSON = 'application/json'.freeze
     DISCOVERY_PATH = 'com.instana.plugin.ruby.discovery'.freeze
 
@@ -30,10 +33,12 @@
       # Two timers, one for each state (unannounced & announced)
       @timers = ::Timers::Group.new
       @announce_timer = nil
       @collect_timer = nil
 
+      @thread_spawn_lock = Mutex.new
+
       # Detect platform flags
       @is_linux = (RUBY_PLATFORM =~ /linux/i) ? true : false
       @is_osx = (RUBY_PLATFORM =~ /darwin/i) ? true : false
 
       # In case we're running in Docker, have the default gateway available
@@ -88,25 +93,28 @@
     #     end
     #   end
     # end
     #
     def spawn_background_thread
-      # The thread calling fork is the only thread in the created child process.
-      # fork doesn’t copy other threads.
-      # Restart our background thread
-      Thread.new do
-        start
-      end
+      @thread_spawn_lock.synchronize {
+        if @collect_thread && @collect_thread.alive?
+          ::Instana.logger.info "[instana] Collect thread already started & alive.  Not spawning another."
+        else
+          @collect_thread = Thread.new do
+            start
+          end
+        end
+      }
     end
 
     # Sets up periodic timers and starts the agent in a background thread.
     #
     def setup
       # The announce timer
       # We attempt to announce this ruby sensor to the host agent.
       # In case of failure, we try again in 30 seconds.
-      @announce_timer = @timers.every(30) do
+      @announce_timer = @timers.now_and_every(30) do
         if @state == :unannounced
           if host_agent_ready? && announce_sensor
             transition_to(:announced)
             ::Instana.logger.warn "Host agent available. We're in business. (#{@state} pid:#{Process.pid} #{@process[:name]})"
           end
@@ -141,9 +149,10 @@
     # in the setup method.  This is blocking and should only be
     # called from an already initialized background thread.
     #
     def start
       ::Instana.logger.warn "Host agent not available.  Will retry periodically." unless host_agent_ready?
+
       loop do
         if @state == :unannounced
           @collect_timer.pause
           @announce_timer.resume
         else