http_poller.rb in logstash-input-http_poller-2.1.0

- old
+ new

@@ -2,10 +2,11 @@
 require "logstash/inputs/base"
 require "logstash/namespace"
 require "logstash/plugin_mixins/http_client"
 require "socket" # for Socket.gethostname
 require "manticore"
+require "rufus/scheduler"
 
 # This Logstash input plugin allows you to call an HTTP API, decode the output of it into event(s), and
 # send them on their merry way. The idea behind this plugins came from a need to read springboot
 # metrics endpoint, instead of configuring jmx to monitor my java application memory/gc/ etc.
 #
@@ -31,11 +32,12 @@
 #           password => "hunter2"
 #         }
 #       }
 #     }
 #     request_timeout => 60
-#     interval => 60
+#     # Supports "cron", "every", "at" and "in" schedules by rufus scheduler
+#     schedule => { cron => "* * * * * UTC"}
 #     codec => "json"
 #     # A hash of request metadata info (timing, response headers, etc.) will be sent here
 #     metadata_target => "http_poller_metadata"
 #   }
 # }
@@ -57,32 +59,47 @@
   # A Hash of urls in this format : `"name" => "url"`.
   # The name and the url will be passed in the outputed event
   config :urls, :validate => :hash, :required => true
 
   # How often (in seconds) the urls will be called
-  config :interval, :validate => :number, :required => true
+  # DEPRECATED. Use 'schedule' option instead.
+  # If both interval and schedule options are specified, interval
+  # option takes higher precedence
+  config :interval, :validate => :number, :deprecated => true
 
+  # Schedule of when to periodically poll from the urls
+  # Format: A hash with
+  #   + key: "cron" | "every" | "in" | "at"
+  #   + value: string
+  # Examples:
+  #   a) { "every" => "1h" }
+  #   b) { "cron" => "* * * * * UTC" }
+  # See: rufus/scheduler for details about different schedule options and value string format
+  config :schedule, :validate => :hash
+
   # Define the target field for placing the received data. If this setting is omitted, the data will be stored at the root (top level) of the event.
   config :target, :validate => :string
 
   # If you'd like to work with the request/response metadata.
   # Set this value to the name of the field you'd like to store a nested
   # hash of metadata.
   config :metadata_target, :validate => :string, :default => '@metadata'
 
   public
+  Schedule_types = %w(cron every at in)
   def register
     @host = Socket.gethostname.force_encoding(Encoding::UTF_8)
 
     @logger.info("Registering http_poller Input", :type => @type,
-                 :urls => @urls, :interval => @interval, :timeout => @timeout)
+                 :urls => @urls, :interval => @interval, :schedule => @schedule, :timeout => @timeout)
 
     setup_requests!
   end
 
   def stop
     Stud.stop!(@interval_thread) if @interval_thread
+    @scheduler.stop if @scheduler
   end
 
   private
   def setup_requests!
     @requests = Hash[@urls.map {|name, url| [name, normalize_request(url)] }]
@@ -131,16 +148,49 @@
     request
   end
 
   public
   def run(queue)
+    #interval or schedule must be provided. Must be exclusively either one. Not neither. Not both.
+    raise LogStash::ConfigurationError, "Invalid config. Neither interval nor schedule was specified." \
+      unless @interval ||  @schedule
+    raise LogStash::ConfigurationError, "Invalid config. Specify only interval or schedule. Not both." \
+      if @interval && @schedule
+
+    if @interval
+      setup_interval(queue)
+    elsif @schedule
+      setup_schedule(queue)
+    else
+      #should not reach here
+      raise LogStash::ConfigurationError, "Invalid config. Neither interval nor schedule was specified."
+    end
+  end
+
+  private
+  def setup_interval(queue)
     @interval_thread = Thread.current
     Stud.interval(@interval) do
       run_once(queue)
     end
   end
 
-  private
+  def setup_schedule(queue)
+    #schedule hash must contain exactly one of the allowed keys
+    msg_invalid_schedule = "Invalid config. schedule hash must contain " +
+      "exactly one of the following keys - cron, at, every or in"
+    raise Logstash::ConfigurationError, msg_invalid_schedule if @schedule.keys.length !=1
+    schedule_type = @schedule.keys.first
+    schedule_value = @schedule[schedule_type]
+    raise LogStash::ConfigurationError, msg_invalid_schedule unless Schedule_types.include?(schedule_type)
+
+    @scheduler = Rufus::Scheduler.new(:max_work_threads => 1)
+    #as of v3.0.9, :first_in => :now doesn't work. Use the following workaround instead
+    opts = schedule_type == "every" ? { :first_in => 0.01 } : {} 
+    @scheduler.send(schedule_type, schedule_value, opts) { run_once(queue) }
+    @scheduler.join
+  end
+
   def run_once(queue)
     @requests.each do |name, request|
       request_async(queue, name, request)
     end
 