Class: LogStash::Outputs::CloudWatch

Inherits:

Base

• Object
• Base
• LogStash::Outputs::CloudWatch

Includes:

PluginMixins::AwsConfig::V2, PluginMixins::Scheduler

Defined in:

lib/logstash/outputs/cloudwatch.rb

Overview

This output lets you aggregate and send metric data to AWS CloudWatch

Summary:

This plugin is intended to be used on a logstash indexer agent (but that is not the only way, see below.) In the intended scenario, one cloudwatch output plugin is configured, on the logstash indexer node, with just AWS API credentials, and possibly a region and/or a namespace. The output looks for fields present in events, and when it finds them, it uses them to calculate aggregate statistics. If the ‘metricname` option is set in this output, then any events which pass through it will be aggregated & sent to CloudWatch, but that is not recommended. The intended use is to NOT set the metricname option here, and instead to add a `CW_metricname` field (and other fields) to only the events you want sent to CloudWatch.

When events pass through this output they are queued for background aggregation and sending, which happens every minute by default. The queue has a maximum size, and when it is full aggregated statistics will be sent to CloudWatch ahead of schedule. Whenever this happens a warning message is written to logstash’s log. If you see this you should increase the ‘queue_size` configuration option to avoid the extra API calls. The queue is emptied every time we send data to CloudWatch.

Note: when logstash is stopped the queue is destroyed before it can be processed. This is a known limitation of logstash and will hopefully be addressed in a future version.

Details:

There are two ways to configure this plugin, and they can be used in combination: event fields & per-output defaults

Event Field configuration… You add fields to your events in inputs & filters and this output reads those fields to aggregate events. The names of the fields read are configurable via the ‘field_*` options.

Per-output defaults… You set universal defaults in this output plugin’s configuration, and if an event does not have a field for that option then the default is used.

Notice, the event fields take precedence over the per-output defaults.

At a minimum events must have a “metric name” to be sent to CloudWatch. This can be achieved either by providing a default here OR by adding a ‘CW_metricname` field. By default, if no other configuration is provided besides a metric name, then events will be counted (Unit: Count, Value: 1) by their metric name (either a default or from their `CW_metricname` field)

Other fields which can be added to events to modify the behavior of this plugin are, ‘CW_namespace`, `CW_unit`, `CW_value`, and `CW_dimensions`. All of these field names are configurable in this output. You can also set per-output defaults for any of them. See below for details.

Read more about aws.amazon.com/cloudwatch/[AWS CloudWatch], and the specific of API endpoint this output uses, docs.amazonwebservices.com/AmazonCloudWatch/latest/APIReference/API_PutMetricData.html[PutMetricData]

Constant Summary

DIMENSIONS =

Constants aggregate_key members

"dimensions"

TIMESTAMP =

"timestamp"

METRIC =

"metric"

COUNT =

"count"

UNIT =

"unit"

SUM =

"sum"

MIN =

"min"

MAX =

"max"

COUNT_UNIT =

Units

"Count"

NONE =

"None"

VALID_UNITS =

["Seconds", "Microseconds", "Milliseconds", "Bytes",
"Kilobytes", "Megabytes", "Gigabytes", "Terabytes",
"Bits", "Kilobits", "Megabits", "Gigabits", "Terabits",
"Percent", COUNT_UNIT, "Bytes/Second", "Kilobytes/Second",
"Megabytes/Second", "Gigabytes/Second", "Terabytes/Second",
"Bits/Second", "Kilobits/Second", "Megabits/Second",
"Gigabits/Second", "Terabits/Second", "Count/Second", NONE]

Instance Attribute Summary

• #event_queue ⇒ Object readonly

  Returns the value of attribute event_queue.

Instance Method Summary

• #receive(event) ⇒ Object
• #register ⇒ Object

Instance Attribute Details

#event_queue ⇒ Object (readonly)

Returns the value of attribute event_queue.

# File 'lib/logstash/outputs/cloudwatch.rb', line 159

def event_queue
  @event_queue
end

Instance Method Details

#receive(event) ⇒ Object

# File 'lib/logstash/outputs/cloudwatch.rb', line 179

def receive(event)
  return unless (event.get(@field_metricname) || @metricname)

  if (@event_queue.length >= @event_queue.max)
    do_publish
    @logger.warn("Posted to AWS CloudWatch ahead of schedule.  If you see this often, consider increasing the cloudwatch queue_size option.")
  end

  @logger.debug? && @logger.debug("Queueing event", :event => event.to_hash)
  @event_queue << event
end

#register ⇒ Object

# File 'lib/logstash/outputs/cloudwatch.rb', line 162

def register
  require "thread"
  require "aws-sdk"

  @cw = Aws::CloudWatch::Client.new(aws_options_hash)

  @event_queue = SizedQueue.new(@queue_size)

  @job = scheduler.every(@timeframe) { do_publish }
end