Class: Aws::CloudWatch::Alarm

Inherits:
Object
  • Object
show all
Defined in:
gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb

Defined Under Namespace

Classes: Collection

Actions collapse

Associations collapse

Read-Only Attributes collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, options = {}) ⇒ Alarm #initialize(options = {}) ⇒ Alarm

Returns a new instance of Alarm.

Overloads:

  • #initialize(name, options = {}) ⇒ Alarm

    Parameters:

    • name (String)

    Options Hash (options):

  • #initialize(options = {}) ⇒ Alarm

    Options Hash (options):

    • :name (required, String)
    • :client (Client)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 20

def initialize(*args)
  options = Hash === args.last ? args.pop.dup : {}
  @name = extract_name(args, options)
  @data = options.delete(:data)
  @client = options.delete(:client) || Client.new(options)
  @waiter_block_warned = false
end

Instance Method Details

#actions_enabledBoolean

Indicates whether actions should be executed during any changes to the alarm state.

Returns:

  • (Boolean)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 57

def actions_enabled
  data[:actions_enabled]
end

#alarm_actionsArray<String>

The actions to execute when this alarm transitions to the ALARM state from any other state. Each action is specified as an Amazon Resource Name (ARN).

Returns:

  • (Array<String>)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 73

def alarm_actions
  data[:alarm_actions]
end

#alarm_arnString

The Amazon Resource Name (ARN) of the alarm.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 38

def alarm_arn
  data[:alarm_arn]
end

#alarm_configuration_updated_timestampTime

The time stamp of the last update to the alarm configuration.

Returns:

  • (Time)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 50

def alarm_configuration_updated_timestamp
  data[:alarm_configuration_updated_timestamp]
end

#alarm_descriptionString

The description of the alarm.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 44

def alarm_description
  data[:alarm_description]
end

#clientClient

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 218

def client
  @client
end

#comparison_operatorString

The arithmetic operation to use when comparing the specified statistic and threshold. The specified statistic value is used as the first operand.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 177

def comparison_operator
  data[:comparison_operator]
end

#dataTypes::MetricAlarm

Returns the data for this Aws::CloudWatch::Alarm. Calls Client#describe_alarms if #data_loaded? is false.

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 238

def data
  load unless @data
  @data
end

#data_loaded?Boolean

Returns true if this resource is loaded. Accessing attributes or #data on an unloaded resource will trigger a call to #load.

Returns:

  • (Boolean)

    Returns true if this resource is loaded. Accessing attributes or #data on an unloaded resource will trigger a call to #load.



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 246

def data_loaded?
  !!@data
end

#datapoints_to_alarmInteger

The number of data points that must be breaching to trigger the alarm.

Returns:

  • (Integer)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 163

def datapoints_to_alarm
  data[:datapoints_to_alarm]
end

#delete(options = {}) ⇒ EmptyStructure

Examples:

Request syntax with placeholder values


alarm.delete()

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Returns:

  • (EmptyStructure)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 385

def delete(options = {})
  options = Aws::Util.deep_merge(options, alarm_names: [@name])
  resp = @client.delete_alarms(options)
  resp.data
end

#describe_history(options = {}) ⇒ Types::DescribeAlarmHistoryOutput

Examples:

Request syntax with placeholder values


alarm.describe_history({
  alarm_types: ["CompositeAlarm"], # accepts CompositeAlarm, MetricAlarm
  history_item_type: "ConfigurationUpdate", # accepts ConfigurationUpdate, StateUpdate, Action
  start_date: Time.now,
  end_date: Time.now,
  max_records: 1,
  next_token: "NextToken",
  scan_by: "TimestampDescending", # accepts TimestampDescending, TimestampAscending
})

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Options Hash (options):

  • :alarm_types (Array<String>)

    Use this parameter to specify whether you want the operation to return metric alarms or composite alarms. If you omit this parameter, only metric alarms are returned.

  • :history_item_type (String)

    The type of alarm histories to retrieve.

  • :start_date (Time, DateTime, Date, Integer, String)

    The starting date to retrieve alarm history.

  • :end_date (Time, DateTime, Date, Integer, String)

    The ending date to retrieve alarm history.

  • :max_records (Integer)

    The maximum number of alarm history records to retrieve.

  • :next_token (String)

    The token returned by a previous call to indicate that there is more data available.

  • :scan_by (String)

    Specified whether to return the newest or oldest alarm history first. Specify TimestampDescending to have the newest event history returned first, and specify TimestampAscending to have the oldest history returned first.

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 424

def describe_history(options = {})
  options = options.merge(alarm_name: @name)
  resp = @client.describe_alarm_history(options)
  resp.data
end

#dimensionsArray<Types::Dimension>

The dimensions for the metric associated with the alarm.

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 138

def dimensions
  data[:dimensions]
end

#disable_actions(options = {}) ⇒ EmptyStructure

Examples:

Request syntax with placeholder values


alarm.disable_actions()

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Returns:

  • (EmptyStructure)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 435

def disable_actions(options = {})
  options = Aws::Util.deep_merge(options, alarm_names: [@name])
  resp = @client.disable_alarm_actions(options)
  resp.data
end

#enable_actions(options = {}) ⇒ EmptyStructure

Examples:

Request syntax with placeholder values


alarm.enable_actions()

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Returns:

  • (EmptyStructure)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 446

def enable_actions(options = {})
  options = Aws::Util.deep_merge(options, alarm_names: [@name])
  resp = @client.enable_alarm_actions(options)
  resp.data
end

#evaluate_low_sample_count_percentileString

Used only for alarms based on percentiles. If ignore, the alarm state does not change during periods with too few data points to be statistically significant. If evaluate or this parameter is not used, the alarm is always evaluated and possibly changes state no matter how many data points are available.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 194

def evaluate_low_sample_count_percentile
  data[:evaluate_low_sample_count_percentile]
end

#evaluation_periodsInteger

The number of periods over which data is compared to the specified threshold.

Returns:

  • (Integer)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 157

def evaluation_periods
  data[:evaluation_periods]
end

#exists?(options = {}) ⇒ Boolean

Returns true if the Alarm exists.

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Returns:

  • (Boolean)

    Returns true if the Alarm exists.



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 253

def exists?(options = {})
  begin
    wait_until_exists(options.merge(max_attempts: 1))
    true
  rescue Aws::Waiters::Errors::UnexpectedError => e
    raise e.error
  rescue Aws::Waiters::Errors::WaiterFailed
    false
  end
end

#extended_statisticString

The percentile statistic for the metric associated with the alarm. Specify a value between p0.0 and p100.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 132

def extended_statistic
  data[:extended_statistic]
end

#insufficient_data_actionsArray<String>

The actions to execute when this alarm transitions to the INSUFFICIENT_DATA state from any other state. Each action is specified as an Amazon Resource Name (ARN).

Returns:

  • (Array<String>)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 81

def insufficient_data_actions
  data[:insufficient_data_actions]
end

#loadself Also known as: reload

Loads, or reloads #data for the current Aws::CloudWatch::Alarm. Returns self making it possible to chain methods.

alarm.reload.data

Returns:

  • (self)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 228

def load
  resp = @client.describe_alarms(alarm_names: [@name])
  @data = resp.metric_alarms[0]
  self
end

#metricMetric?

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 483

def metric
  if data[:namespace] && data[:metric_name]
    Metric.new(
      namespace: data[:namespace],
      name: data[:metric_name],
      client: @client
    )
  else
    nil
  end
end

#metric_nameString

The name of the metric associated with the alarm, if this is an alarm based on a single metric.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 112

def metric_name
  data[:metric_name]
end

#metricsArray<Types::MetricDataQuery>

An array of MetricDataQuery structures, used in an alarm based on a metric math expression. Each structure either retrieves a metric or performs a math expression. One item in the Metrics array is the math expression that the alarm watches. This expression by designated by having ReturnValue set to true.

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 204

def metrics
  data[:metrics]
end

#nameString Also known as: alarm_name

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 31

def name
  @name
end

#namespaceString

The namespace of the metric associated with the alarm.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 118

def namespace
  data[:namespace]
end

#ok_actionsArray<String>

The actions to execute when this alarm transitions to the OK state from any other state. Each action is specified as an Amazon Resource Name (ARN).

Returns:

  • (Array<String>)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 65

def ok_actions
  data[:ok_actions]
end

#periodInteger

The period, in seconds, over which the statistic is applied.

Returns:

  • (Integer)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 144

def period
  data[:period]
end

#set_state(options = {}) ⇒ EmptyStructure

Examples:

Request syntax with placeholder values


alarm.set_state({
  state_value: "OK", # required, accepts OK, ALARM, INSUFFICIENT_DATA
  state_reason: "StateReason", # required
  state_reason_data: "StateReasonData",
})

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Options Hash (options):

  • :state_value (required, String)

    The value of the state.

  • :state_reason (required, String)

    The reason that this alarm is set to this specific state, in text format.

  • :state_reason_data (String)

    The reason that this alarm is set to this specific state, in JSON format.

    For SNS or EC2 alarm actions, this is just informational. But for EC2 Auto Scaling or application Auto Scaling alarm actions, the Auto Scaling policy uses the information in this field to take the correct action.

Returns:

  • (EmptyStructure)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 474

def set_state(options = {})
  options = options.merge(alarm_name: @name)
  resp = @client.set_alarm_state(options)
  resp.data
end

#state_reasonString

An explanation for the alarm state, in text format.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 93

def state_reason
  data[:state_reason]
end

#state_reason_dataString

An explanation for the alarm state, in JSON format.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 99

def state_reason_data
  data[:state_reason_data]
end

#state_updated_timestampTime

The time stamp of the last update to the alarm state.

Returns:

  • (Time)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 105

def state_updated_timestamp
  data[:state_updated_timestamp]
end

#state_valueString

The state value for the alarm.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 87

def state_value
  data[:state_value]
end

#statisticString

The statistic for the metric associated with the alarm, other than percentile. For percentile statistics, use ExtendedStatistic.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 125

def statistic
  data[:statistic]
end

#thresholdFloat

The value to compare with the specified statistic.

Returns:

  • (Float)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 169

def threshold
  data[:threshold]
end

#threshold_metric_idString

In an alarm based on an anomaly detection model, this is the ID of the ANOMALY_DETECTION_BAND function used as the threshold for the alarm.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 211

def threshold_metric_id
  data[:threshold_metric_id]
end

#treat_missing_dataString

Sets how this alarm is to handle missing data points. If this parameter is omitted, the default behavior of missing is used.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 184

def treat_missing_data
  data[:treat_missing_data]
end

#unitString

The unit of the metric associated with the alarm.

Returns:

  • (String)


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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 150

def unit
  data[:unit]
end

#wait_until(options = {}) {|resource| ... } ⇒ Resource

Deprecated.

Use [Aws::CloudWatch::Client] #wait_until instead

Note:

The waiting operation is performed on a copy. The original resource remains unchanged.

Waiter polls an API operation until a resource enters a desired state.

Basic Usage

Waiter will polls until it is successful, it fails by entering a terminal state, or until a maximum number of attempts are made.

# polls in a loop until condition is true
resource.wait_until(options) {|resource| condition}

Example

instance.wait_until(max_attempts:10, delay:5) do |instance|
  instance.state.name == 'running'
end

Configuration

You can configure the maximum number of polling attempts, and the delay (in seconds) between each polling attempt. The waiting condition is set by passing a block to #wait_until:

# poll for ~25 seconds
resource.wait_until(max_attempts:5,delay:5) {|resource|...}

Callbacks

You can be notified before each polling attempt and before each delay. If you throw :success or :failure from these callbacks, it will terminate the waiter.

started_at = Time.now
# poll for 1 hour, instead of a number of attempts
proc = Proc.new do |attempts, response|
  throw :failure if Time.now - started_at > 3600
end

  # disable max attempts
instance.wait_until(before_wait:proc, max_attempts:nil) {...}

Handling Errors

When a waiter is successful, it returns the Resource. When a waiter fails, it raises an error.

begin
  resource.wait_until(...)
rescue Aws::Waiters::Errors::WaiterFailed
  # resource did not enter the desired state in time
end

attempts attempt in seconds invoked before each attempt invoked before each wait

Parameters:

  • options (Hash) (defaults to: {})

    a customizable set of options

Options Hash (options):

  • :max_attempts (Integer) — default: 10

    Maximum number of

  • :delay (Integer) — default: 10

    Delay between each

  • :before_attempt (Proc) — default: nil

    Callback

  • :before_wait (Proc) — default: nil

    Callback

Yield Parameters:

  • resource (Resource)

    to be used in the waiting condition.

Returns:

  • (Resource)

    if the waiter was successful

Raises:

  • (Aws::Waiters::Errors::FailureStateError)

    Raised when the waiter terminates because the waiter has entered a state that it will not transition out of, preventing success.

    yet successful.

  • (Aws::Waiters::Errors::UnexpectedError)

    Raised when an error is encountered while polling for a resource that is not expected.

  • (NotImplementedError)

    Raised when the resource does not



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 361

def wait_until(options = {}, &block)
  self_copy = self.dup
  attempts = 0
  options[:max_attempts] = 10 unless options.key?(:max_attempts)
  options[:delay] ||= 10
  options[:poller] = Proc.new do
    attempts += 1
    if block.call(self_copy)
      [:success, self_copy]
    else
      self_copy.reload unless attempts == options[:max_attempts]
      :retry
    end
  end
  Aws::Waiters::Waiter.new(options).wait({})
end

#wait_until_exists(options = {}, &block) ⇒ Alarm

Parameters:

  • options (Hash) (defaults to: {})

    ({})

Options Hash (options):

  • :max_attempts (Integer) — default: 40
  • :delay (Float) — default: 5
  • :before_attempt (Proc)
  • :before_wait (Proc)

Returns:



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# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 270

def wait_until_exists(options = {}, &block)
  options, params = separate_params_and_options(options)
  waiter = Waiters::AlarmExists.new(options)
  yield_waiter_and_warn(waiter, &block) if block_given?
  waiter.wait(params.merge(alarm_names: [@name]))
  Alarm.new({
    name: @name,
    client: @client
  })
end