Class: LogStash::Outputs::Graphite

Inherits:
Base
  • Object
show all
Defined in:
lib/logstash/outputs/graphite.rb

Overview

This output allows you to pull metrics from your logs and ship them to Graphite. Graphite is an open source tool for storing and graphing metrics.

An example use case: Some applications emit aggregated stats in the logs every 10 seconds. Using the grok filter and this output, it is possible to capture the metric values from the logs and emit them to Graphite.

Constant Summary collapse

EXCLUDE_ALWAYS = 
[ "@timestamp", "@version" ]
DEFAULT_METRICS_FORMAT = 
"*"
METRIC_PLACEHOLDER = 
"*"

Instance Method Summary collapse

Instance Method Details

#connect ⇒ Object 



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# File 'lib/logstash/outputs/graphite.rb', line 92

def connect
  # TODO(sissel): Test error cases. Catch exceptions. Find fortune and glory. Retire to yak farm.
  begin
    @socket = TCPSocket.new(@host, @port)
  rescue Errno::ECONNREFUSED => e
    @logger.warn("Connection refused to graphite server, sleeping...", :host => @host, :port => @port)
    sleep(@reconnect_interval)
    retry
  end
end

#construct_metric_name(event, metric) ⇒ Object 



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# File 'lib/logstash/outputs/graphite.rb', line 103

def construct_metric_name(event, metric)
  if @metrics_format
    sprinted = event.sprintf(@metrics_format)
    return sprinted.gsub(METRIC_PLACEHOLDER, metric)
  end

  metric
end

#receive(event) ⇒ Object 



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# File 'lib/logstash/outputs/graphite.rb', line 112

def receive(event)
  # Graphite message format: metric value timestamp\n

  # compact to remove nil messages which produces useless \n
  messages = (
    @fields_are_metrics \
      ? messages_from_event_fields(event, @include_metrics, @exclude_metrics)
      : messages_from_event_metrics(event, @metrics)
  ).compact

  if messages.empty?
    @logger.debug? && @logger.debug("Message is empty, not sending anything to Graphite", :messages => messages, :host => @host, :port => @port)
  else
    message = messages.join("\n")
    @logger.debug? && @logger.debug("Sending carbon messages", :messages => messages, :host => @host, :port => @port)

    # Catch exceptions like ECONNRESET and friends, reconnect on failure.
    # TODO(sissel): Test error cases. Catch exceptions. Find fortune and glory.
    begin
      @socket.puts(message)
    rescue Errno::EPIPE, Errno::ECONNRESET, IOError => e
      @logger.warn("Connection to graphite server died", :exception => e, :host => @host, :port => @port)
      sleep(@reconnect_interval)
      connect
      retry if @resend_on_failure
    end
  end
end

#register ⇒ Object 



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# File 'lib/logstash/outputs/graphite.rb', line 79

def register
  @include_metrics.collect!{|regexp| Regexp.new(regexp)}
  @exclude_metrics.collect!{|regexp| Regexp.new(regexp)}

  if @metrics_format && !@metrics_format.include?(METRIC_PLACEHOLDER)
    @logger.warn("metrics_format does not include placeholder #{METRIC_PLACEHOLDER} .. falling back to default format: #{DEFAULT_METRICS_FORMAT.inspect}")

    @metrics_format = DEFAULT_METRICS_FORMAT
  end

  connect
end