config_skeleton.rb in config_skeleton-0.2.6

- old
+ new

@@ -140,10 +140,22 @@
   class Error < StandardError; end
 
   # If you get this, someone didn't read the documentation.
   class NotImplementedError < Error; end
 
+  # It is useful for consumers to manually request a config regen. An instance
+  # of this class is made via the regen_notifier method.
+  class ConfigRegenNotifier
+    def initialize(io_write)
+      @io_write = io_write
+    end
+
+    def trigger_regen
+      @io_write << "."
+    end
+  end
+
   # Declare a file watch on all instances of the config generator.
   #
   # When you're looking to watch a file whose path is well-known and never-changing, you
   # can declare the watch in the class.
   #
@@ -186,12 +198,24 @@
       logger.info("SIGHUP") { "received SIGHUP, triggering config regeneration" }
       regenerate_config(force_reload: true)
     end
 
     initialize_config_skeleton_metrics
+    @trigger_regen_r, @trigger_regen_w = IO.pipe
   end
 
+  # Expose the write pipe which can be written to to trigger a config
+  # regeneration with a forced reload; a similar mechanism is used for
+  # shutdown but in that case writes are managed internally.
+  #
+  # Usage: config.regen_notifier.trigger_regen
+  #
+  # @return [ConfigRegenNotifier]
+  def regen_notifier
+    @regen_notifier ||= ConfigRegenNotifier.new(@trigger_regen_w)
+  end
+
   # Set the config generator running.
   #
   # Does the needful to generate configs and reload the server.  Typically
   # never returns, unless you send the process a `SIGTERM`/`SIGINT`.
   #
@@ -207,17 +231,29 @@
     logger.debug(logloc) { "notifier fd is #{notifier.to_io.inspect}" }
 
     @terminate_r, @terminate_w = IO.pipe
 
     loop do
-      if ios = IO.select([notifier.to_io, @terminate_r], [], [], sleep_duration.tap { |d| logger.debug(logloc) { "Sleeping for #{d} seconds" } })
+      if ios = IO.select(
+          [notifier.to_io, @terminate_r, @trigger_regen_r],
+          [], [],
+          sleep_duration.tap { |d| logger.debug(logloc) { "Sleeping for #{d} seconds" } }
+      )
         if ios.first.include?(notifier.to_io)
           logger.debug(logloc) { "inotify triggered" }
           notifier.process
           regenerate_config(force_reload: true)
         elsif ios.first.include?(@terminate_r)
           logger.debug(logloc) { "triggered by termination pipe" }
           break
+        elsif ios.first.include?(@trigger_regen_r)
+          # we want to wait until everything in the backlog is read
+          # before proceeding so we don't run out of buffer memory
+          # for the pipe
+          while @trigger_regen_r.read_nonblock(20, nil, exception: false) != :wait_readable; end
+
+          logger.debug(logloc) { "triggered by regen pipe" }
+          regenerate_config(force_reload: true)
         else
           logger.error(logloc) { "Mysterious return from select: #{ios.inspect}" }
         end
       else
         logger.debug(logloc) { "triggered by timeout" }