Class: MultiStatsd::Backend::Hottie

Inherits:
Base
  • Object
show all
Defined in:
lib/multi-statsd/backends/hottie.rb

Overview

Hottie backend Hottie is a redis-based short-term backend to enable real-time visibility into application behavior. It is specifically designed to enable real-time heatmap/histogram visualizations from timer data.

Instance Attribute Summary collapse

Attributes inherited from Base

#counters, #gauges, #name, #timers

Instance Method Summary collapse

Methods inherited from Base

#flush_interval, #format_key, #initialize, #reset_stats, #write

Constructor Details

This class inherits a constructor from MultiStatsd::Backend::Base

Instance Attribute Details

#samples_to_retain ⇒ Object (readonly)

Returns the value of attribute samples_to_retain.



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# File 'lib/multi-statsd/backends/hottie.rb', line 7

def samples_to_retain
  @samples_to_retain
end

#seconds_to_retain ⇒ Object (readonly)

Returns the value of attribute seconds_to_retain.



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# File 'lib/multi-statsd/backends/hottie.rb', line 7

def seconds_to_retain
  @seconds_to_retain
end

Instance Method Details

#flush ⇒ Float

Flush the data to redis in the format required for Hottie

Returns:

  • (Float) —

    The number of seconds it took to aggregate/flush the data to redis



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# File 'lib/multi-statsd/backends/hottie.rb', line 22

def flush
  counters, timers, gauges = reset_stats
  ts = Time.new.to_i
  time = ::Benchmark.realtime do
    @db.pipelined do
      if !gauges.empty?
        @db.hmset "gauges:#{ts}", *(gauges.map { |stat, gauge|  [stat, gauge] }.flatten)
        @db.expire "gauges:#{ts}", @seconds_to_retain + 5 # Retain a few extra seconds to avoid reporting race
        @db.sadd "gauges", gauges.keys
      end
      @db.lpush "gauge_samples", "gauges:#{ts}"
      @db.ltrim "gauge_samples", 0, @samples_to_retain - 1

      if !counters.empty?
        @db.hmset "counters:#{ts}", *(counters.map { |stat, counter|[stat, counter / @options['flush_interval']] }.flatten)
        @db.expire "counters:#{ts}", @seconds_to_retain + 5 # Retain a few extra seconds to avoid reporting race
        @db.sadd "counters", counters.keys
      end
      @db.lpush "counter_samples", "counters:#{ts}"
      @db.ltrim "counter_samples", 0, @samples_to_retain - 1

      if !timers.empty?
        timer_hash = Hash.new(0)
        @db.hmset "timers:#{ts}", *(timers.map { |stat, data|
          timer_hash.clear
          data.each { |d| timer_hash[d.round] += 1 }
          [stat, Marshal.dump(timer_hash)]
        })
        @db.expire "timers:#{ts}", @seconds_to_retain + 5 # Retain a few extra seconds to avoid reporting race
        @db.sadd "timers", timers.keys
      end
      @db.lpush "timer_samples", "timers:#{ts}"
      @db.ltrim "timer_samples", 0, @samples_to_retain - 1
    end
  end
  MultiStatsd.logger.debug "Hottie flushing took #{"%.3f" % (time * 1000)}ms"
  time
rescue Redis::CannotConnectError
  MultiStatsd.logger.warning "Unable to connect to redis, skipping flush"
end

#post_init ⇒ Object

Initialize a connection to redis and configure our samples to retain



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# File 'lib/multi-statsd/backends/hottie.rb', line 10

def post_init
  @db = Redis.new(
    :host => (@options['host'] || '127.0.0.1'),
    :port => (@options['port'] || 6379),
    :database => (@options['database'] || 1)
  )
  @seconds_to_retain = @options['seconds_to_retain'] || 60
  @samples_to_retain = (@seconds_to_retain / @options['flush_interval']).floor
end