Getting Information about Amazon CloudWatch Alarms

The following code example displays information about available metric alarms in Amazon CloudWatch.

# Copyright Amazon.com, Inc. or its affiliates. All Rights Reserved.
# SPDX-License-Identifier: Apache-2.0

require 'aws-sdk-cloudwatch'

# Displays information about available metric alarms in Amazon CloudWatch.
#
# @param cloudwatch_client [Aws::CloudWatch::Client]
#   An initialized CloudWatch client.
# @example
#   describe_metric_alarms(Aws::CloudWatch::Client.new(region: 'us-east-1'))
def describe_metric_alarms(cloudwatch_client)
  response = cloudwatch_client.describe_alarms

  if response.metric_alarms.count.positive?
    response.metric_alarms.each do |alarm|
      puts '-' * 16
      puts 'Name:           ' + alarm.alarm_name
      puts 'State value:    ' + alarm.state_value
      puts 'State reason:   ' + alarm.state_reason
      puts 'Metric:         ' + alarm.metric_name
      puts 'Namespace:      ' + alarm.namespace
      puts 'Statistic:      ' + alarm.statistic
      puts 'Period:         ' + alarm.period.to_s
      puts 'Unit:           ' + alarm.unit.to_s
      puts 'Eval. periods:  ' + alarm.evaluation_periods.to_s
      puts 'Threshold:      ' + alarm.threshold.to_s
      puts 'Comp. operator: ' + alarm.comparison_operator

      if alarm.key?(:ok_actions) && alarm.ok_actions.count.positive?
        puts 'OK actions:'
        alarm.ok_actions.each do |a|
          puts '  ' + a
        end
      end

      if alarm.key?(:alarm_actions) && alarm.alarm_actions.count.positive?
        puts 'Alarm actions:'
        alarm.alarm_actions.each do |a|
          puts '  ' + a
        end
      end

      if alarm.key?(:insufficient_data_actions) &&
          alarm.insufficient_data_actions.count.positive?
        puts 'Insufficient data actions:'
        alarm.insufficient_data_actions.each do |a|
          puts '  ' + a
        end
      end

      puts 'Dimensions:'
      if alarm.key?(:dimensions) && alarm.dimensions.count.positive?
        alarm.dimensions.each do |d|
          puts '  Name: ' + d.name + ', Value: ' + d.value
        end
      else
        puts '  None for this alarm.'
      end
    end
  else
    puts 'No alarms found.'
  end
rescue StandardError => e
  puts "Error getting information about alarms: #{e.message}"
end

# Full example call:
def run_me
  region = ''

  # Print usage information and then stop.
  if ARGV[0] == '--help' || ARGV[0] == '-h'
    puts 'Usage:   ruby cw-ruby-example-show-alarms.rb REGION'
    puts 'Example: ruby cw-ruby-example-show-alarms.rb us-east-1'
    exit 1
  # If no values are specified at the command prompt, use these default values.
  elsif ARGV.count.zero?
    region = 'us-east-1'
  # Otherwise, use the values as specified at the command prompt.
  else
    region = ARGV[0]
  end

  cloudwatch_client = Aws::CloudWatch::Client.new(region: region)
  puts 'Available alarms:'
  describe_metric_alarms(cloudwatch_client)
end

run_me if $PROGRAM_NAME == __FILE__