background_parse.rb in nagira-0.5.1

- old
+ new
@@ -1,31 +1,123 @@
-require 'nagios'
-
-module Nagios
+class Nagira < Sinatra::Base
   ##
   # Background parsing of status.dat file in separate thread. Runs on
-  # regular intervals slightly shorter than :ttl
+  # regular intervals defined by :ttl
   #
   class BackgroundParser
+    include Singleton
 
-    ##
-    # 
-    # If :ttl is not defined set to 0 and do not run
-    # background parsing.
-    #
     def initialize
-      interval = [::DEFAULT[:ttl],1].max || nil
-      $use_inflight_status = false
-      $use_inflight_objects = false
-      if interval && ::DEFAULT[:start_background_parser]
-        puts "[#{Time.now}] Starting background parser thread with interval #{interval} sec"
-        $bg = Thread.new {
-          loop {
-            $use_inflight_status ? $nagios[:status].parse : $nagios[:status_inflight].parse
-            $use_inflight_status = !$use_inflight_status
-            sleep interval
-          } #loop
-        } # thread
+      @use_inflight_flag = false
+    end
+
+    #  For large Nagios files there's a significant time required for
+    #  the parsing, if HTTP request comes during the parsing, data
+    #  could be missing. To prevent this from happening flag variable
+    #  defines two sets of the parsed data, which are parsed at
+    #  different sequential runs of the parser.
+    attr_accessor :use_inflight_flag
+
+    class << self
+
+      ##
+      # Target data structure (i.e. $nagios hash for example) which is
+      # updated by BackgroundParser.
+      #
+      def target
+        @target ||= Parser.state
       end
+
+      ##
+      # \@ttl (Fixint, seconds) defines re-parsing interval for the
+      # BackgroundParser.
+      #
+      # Set @@ttl after initialization, to be able to pass
+      #  configuration variables.
+      #
+      # @see start=
+      #
+      # Example:
+      #     Nagios::BackgroundParser.ttl = ::DEFAULT[:ttl].to_i
+      #     Nagios::BackgroundParser.start = ::DEFAULT[:start_background_parser]
+      #     Nagios::BackgroundParser.run
+      #
+      def ttl= ttl
+        @ttl = ttl
+      end
+
+      ##
+      # \@start (Boolean) defines whether BackgroundParser should be
+      # started.
+      #
+      # Set :start variable after initialization, to be able to pass
+      #  configuration values.
+      #
+      # @see ttl=
+      #
+      # Example:
+      #     Nagios::BackgroundParser.ttl = ::DEFAULT[:ttl].to_i
+      #     Nagios::BackgroundParser.start = ::DEFAULT[:start_background_parser]
+      #     Nagios::BackgroundParser.run
+      #
+      def start= start
+        @start = start
+      end
+
+      ##
+      # Is BackgroundParser configured to run?
+      def configured?
+        @ttl > 0 && @start
+      end
+
+      ##
+      # Is BG parser thread running
+      #
+      def alive?
+        !@bg.nil? && @bg.alive?
+      end
+
+      ##
+      # See alive?
+      def dead?
+        !alive?
+      end
+
+
+      ##
+      # Start BG Parser if it's configured to run and TTL is defined
+      def run
+        if configured? && dead?
+
+          Logger.log "Starting background parser thread with interval #{@ttl} sec"
+
+          target.status_inflight = Nagios::Status.new(target[:status].path)
+          target.objects_inflight = Nagios::Objects.new(target[:objects].path)
+
+          Parser.parse [:status_inflight,:objects_inflight]
+
+          @bg = Thread.new {
+            loop {
+              target[with_inflight?(:status)].parse
+              target[with_inflight?(:objects)].parse
+              sleep @ttl
+              @use_inflight_flag = !@use_inflight_flag
+            }
+          }
+        end
+      end
+
+      def inflight?
+        @use_inflight_flag
+      end
+      ##
+      # Construct file symbol, based on in flight status.
+      # @see run
+      def with_inflight?(file)
+        (inflight? ? "#{file}_inflight" : file).to_sym
+      end
+
     end
   end
 end
+
+#  LocalWords:  ttl BackgroundParser config param Fixint