CloudWatch examples using SDK for Ruby

require "aws-sdk-cloudwatch"

# Lists the names of available Amazon CloudWatch alarms.
#
# @param cloudwatch_client [Aws::CloudWatch::Client]
#   An initialized CloudWatch client.
# @example
#   list_alarms(Aws::CloudWatch::Client.new(region: 'us-east-1'))
def list_alarms(cloudwatch_client)
  response = cloudwatch_client.describe_alarms
  if response.metric_alarms.count.positive?
    response.metric_alarms.each do |alarm|
      puts alarm.alarm_name
    end
  else
    puts "No alarms found."
  end
rescue StandardError => e
  puts "Error getting information about alarms: #{e.message}"
end

#
# @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

# Example usage:
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__

# Disables an alarm in Amazon CloudWatch.
#
# Prerequisites.
#
# - The alarm to disable.
#
# @param cloudwatch_client [Aws::CloudWatch::Client]
#   An initialized CloudWatch client.
# @param alarm_name [String] The name of the alarm to disable.
# @return [Boolean] true if the alarm was disabled; otherwise, false.
# @example
#   exit 1 unless alarm_actions_disabled?(
#     Aws::CloudWatch::Client.new(region: 'us-east-1'),
#     'ObjectsInBucket'
#   )
def alarm_actions_disabled?(cloudwatch_client, alarm_name)
  cloudwatch_client.disable_alarm_actions(alarm_names: [alarm_name])
  return true
rescue StandardError => e
  puts "Error disabling alarm actions: #{e.message}"
  return false
end

# Example usage:
def run_me
  alarm_name = "ObjectsInBucket"
  alarm_description = "Objects exist in this bucket for more than 1 day."
  metric_name = "NumberOfObjects"
  # Notify this Amazon Simple Notification Service (Amazon SNS) topic when
  # the alarm transitions to the ALARM state.
  alarm_actions = ["arn:aws:sns:us-east-1:111111111111:Default_CloudWatch_Alarms_Topic"]
  namespace = "AWS/S3"
  statistic = "Average"
  dimensions = [
    {
      name: "BucketName",
      value: "doc-example-bucket"
    },
    {
      name: "StorageType",
      value: "AllStorageTypes"
    }
  ]
  period = 86_400 # Daily (24 hours * 60 minutes * 60 seconds = 86400 seconds).
  unit = "Count"
  evaluation_periods = 1 # More than one day.
  threshold = 1 # One object.
  comparison_operator = "GreaterThanThreshold" # More than one object.
  # Replace us-west-2 with the AWS Region you're using for Amazon CloudWatch.
  region = "us-east-1"

  cloudwatch_client = Aws::CloudWatch::Client.new(region: region)

  if alarm_created_or_updated?(
    cloudwatch_client,
    alarm_name,
    alarm_description,
    metric_name,
    alarm_actions,
    namespace,
    statistic,
    dimensions,
    period,
    unit,
    evaluation_periods,
    threshold,
    comparison_operator
  )
    puts "Alarm '#{alarm_name}' created or updated."
  else
    puts "Could not create or update alarm '#{alarm_name}'."
  end

  if alarm_actions_disabled?(cloudwatch_client, alarm_name)
    puts "Alarm '#{alarm_name}' disabled."
  else
    puts "Could not disable alarm '#{alarm_name}'."
  end
end

run_me if $PROGRAM_NAME == __FILE__

# Lists available metrics for a metric namespace in Amazon CloudWatch.
#
# @param cloudwatch_client [Aws::CloudWatch::Client]
#   An initialized CloudWatch client.
# @param metric_namespace [String] The namespace of the metric.
# @example
#   list_metrics_for_namespace(
#     Aws::CloudWatch::Client.new(region: 'us-east-1'),
#     'SITE/TRAFFIC'
#   )
def list_metrics_for_namespace(cloudwatch_client, metric_namespace)
  response = cloudwatch_client.list_metrics(namespace: metric_namespace)

  if response.metrics.count.positive?
    response.metrics.each do |metric|
      puts "  Metric name: #{metric.metric_name}"
      if metric.dimensions.count.positive?
        puts "    Dimensions:"
        metric.dimensions.each do |dimension|
          puts "      Name: #{dimension.name}, Value: #{dimension.value}"
        end
      else
        puts "No dimensions found."
      end
    end
  else
    puts "No metrics found for namespace '#{metric_namespace}'. " \
      "Note that it could take up to 15 minutes for recently-added metrics " \
      "to become available."
  end
end

# Example usage:
def run_me
  metric_namespace = "SITE/TRAFFIC"
  # Replace us-west-2 with the AWS Region you're using for Amazon CloudWatch.
  region = "us-east-1"

  cloudwatch_client = Aws::CloudWatch::Client.new(region: region)

  # Add three datapoints.
  puts "Continuing..." unless datapoint_added_to_metric?(
    cloudwatch_client,
    metric_namespace,
    "UniqueVisitors",
    "SiteName",
    "example.com",
    5_885.0,
    "Count"
  )

  puts "Continuing..." unless datapoint_added_to_metric?(
    cloudwatch_client,
    metric_namespace,
    "UniqueVisits",
    "SiteName",
    "example.com",
    8_628.0,
    "Count"
  )

  puts "Continuing..." unless datapoint_added_to_metric?(
    cloudwatch_client,
    metric_namespace,
    "PageViews",
    "PageURL",
    "example.html",
    18_057.0,
    "Count"
  )

  puts "Metrics for namespace '#{metric_namespace}':"
  list_metrics_for_namespace(cloudwatch_client, metric_namespace)
end

run_me if $PROGRAM_NAME == __FILE__

# Creates or updates an alarm in Amazon CloudWatch.
#
# @param cloudwatch_client [Aws::CloudWatch::Client]
#   An initialized CloudWatch client.
# @param alarm_name [String] The name of the alarm.
# @param alarm_description [String] A description about the alarm.
# @param metric_name [String] The name of the metric associated with the alarm.
# @param alarm_actions [Array] A list of Strings representing the
#   Amazon Resource Names (ARNs) to execute when the alarm transitions to the
#   ALARM state.
# @param namespace [String] The namespace for the metric to alarm on.
# @param statistic [String] The statistic for the metric.
# @param dimensions [Array] A list of dimensions for the metric, specified as
#   Aws::CloudWatch::Types::Dimension.
# @param period [Integer] The number of seconds before re-evaluating the metric.
# @param unit [String] The unit of measure for the statistic.
# @param evaluation_periods [Integer] The number of periods over which data is
#   compared to the specified threshold.
# @param theshold [Float] The value against which the specified statistic is compared.
# @param comparison_operator [String] The arithmetic operation to use when
#   comparing the specified statistic and threshold.
# @return [Boolean] true if the alarm was created or updated; otherwise, false.
# @example
#   exit 1 unless alarm_created_or_updated?(
#     Aws::CloudWatch::Client.new(region: 'us-east-1'),
#     'ObjectsInBucket',
#     'Objects exist in this bucket for more than 1 day.',
#     'NumberOfObjects',
#     ['arn:aws:sns:us-east-1:111111111111:Default_CloudWatch_Alarms_Topic'],
#     'AWS/S3',
#     'Average',
#     [
#       {
#         name: 'BucketName',
#         value: 'doc-example-bucket'
#       },
#       {
#         name: 'StorageType',
#         value: 'AllStorageTypes'
#       }
#     ],
#     86_400,
#     'Count',
#     1,
#     1,
#     'GreaterThanThreshold'
#   )
def alarm_created_or_updated?(
  cloudwatch_client,
  alarm_name,
  alarm_description,
  metric_name,
  alarm_actions,
  namespace,
  statistic,
  dimensions,
  period,
  unit,
  evaluation_periods,
  threshold,
  comparison_operator
)
  cloudwatch_client.put_metric_alarm(
    alarm_name: alarm_name,
    alarm_description: alarm_description,
    metric_name: metric_name,
    alarm_actions: alarm_actions,
    namespace: namespace,
    statistic: statistic,
    dimensions: dimensions,
    period: period,
    unit: unit,
    evaluation_periods: evaluation_periods,
    threshold: threshold,
    comparison_operator: comparison_operator
  )
  return true
rescue StandardError => e
  puts "Error creating alarm: #{e.message}"
  return false
end

require "aws-sdk-cloudwatch"

# Adds a datapoint to a metric in Amazon CloudWatch.
#
# @param cloudwatch_client [Aws::CloudWatch::Client]
#   An initialized CloudWatch client.
# @param metric_namespace [String] The namespace of the metric to add the
#   datapoint to.
# @param metric_name [String] The name of the metric to add the datapoint to.
# @param dimension_name [String] The name of the dimension to add the
#   datapoint to.
# @param dimension_value [String] The value of the dimension to add the
#   datapoint to.
# @param metric_value [Float] The value of the datapoint.
# @param metric_unit [String] The unit of measurement for the datapoint.
# @return [Boolean]
# @example
#   exit 1 unless datapoint_added_to_metric?(
#     Aws::CloudWatch::Client.new(region: 'us-east-1'),
#     'SITE/TRAFFIC',
#     'UniqueVisitors',
#     'SiteName',
#     'example.com',
#     5_885.0,
#     'Count'
#   )
def datapoint_added_to_metric?(
  cloudwatch_client,
  metric_namespace,
  metric_name,
  dimension_name,
  dimension_value,
  metric_value,
  metric_unit
)
  cloudwatch_client.put_metric_data(
    namespace: metric_namespace,
    metric_data: [
      {
        metric_name: metric_name,
        dimensions: [
          {
            name: dimension_name,
            value: dimension_value
          }
        ],
        value: metric_value,
        unit: metric_unit
      }
    ]
  )
  puts "Added data about '#{metric_name}' to namespace " \
    "'#{metric_namespace}'."
  return true
rescue StandardError => e
  puts "Error adding data about '#{metric_name}' to namespace " \
    "'#{metric_namespace}': #{e.message}"
  return false
end