- only yield to Agent#run's block when all inputs and outputs have been

registered. Consider it like a 'ready' callback.

lib/logstash/agent.rb

@@ -213,7 +213,7 @@ class LogStash::Agent
   end # def configure
 
   public
-  def run
+  def run(&block)
     LogStash::Util::set_thread_name(self.class.name)
 
     ok = parse_options
@@ -226,7 +226,7 @@ class LogStash::Agent
     # Load the config file
     config = LogStash::Config::File.new(@config_file)
 
-    run_with_config(config)
+    run_with_config(config, &block)
   end # def run
 
   def run_with_config(config)
@@ -265,6 +265,8 @@ class LogStash::Agent
     filter_queue = SizedQueue.new(10)
     output_queue = LogStash::MultiQueue.new
 
+    ready_queue = Queue.new
+
     input_target = @filters.length > 0 ? filter_queue : output_queue
     # Start inputs
     @inputs.each do |input|
@@ -272,6 +274,7 @@ class LogStash::Agent
       @threads[input] = Thread.new(input_target) do |input_target|
         input.logger = @logger
         input.register
+        ready_queue << input
         input.run(input_target)
       end # new thread for thsi input
     end # @inputs.each
@@ -313,6 +316,7 @@ class LogStash::Agent
       output_queue.add_queue(queue)
       @threads["outputs/#{output.to_s}"] = Thread.new(queue) do |queue|
         output.register
+        ready_queue << output
         begin
           LogStash::Util::set_thread_name("output/#{output.to_s}")
           output.logger = @logger
@@ -323,18 +327,26 @@ class LogStash::Agent
           end
         rescue Exception => e
           @logger.warn(["Output #{output.to_s} thread exception", e])
+          # TODO(sissel): should we abort after too many failures?
           retry
-        end
+        end # begin/rescue
       end # Thread.new
     end # @outputs.each
 
+    # Wait for all inputs and outputs to be registered.
+    wait_count = outputs.size + inputs.size
+    while wait_count > 0 and ready_queue.pop 
+      wait_count -= 1
+    end
+
     # yield to a block in case someone's waiting for us to be done setting up
     # like tests, etc.
     yield if block_given?
 
+    # TODO(sissel): Monitor what's going on? Sleep forever? what?
     while sleep 5
     end
-  end # def run
+  end # def run_with_config
 
   public
   def stop