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

Read-Only Attributes collapse

Actions collapse

Associations 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) 


22
23
24
25
26
27
28
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 22

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_enabled ⇒ Boolean

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

Returns:

  • (Boolean) 


59
60
61
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 59

def actions_enabled
  data[:actions_enabled]
end

#alarm_actions ⇒ Array<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>) 


75
76
77
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 75

def alarm_actions
  data[:alarm_actions]
end

#alarm_arn ⇒ String

The Amazon Resource Name (ARN) of the alarm.

Returns:

  • (String) 


40
41
42
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 40

def alarm_arn
  data[:alarm_arn]
end

#alarm_configuration_updated_timestamp ⇒ Time

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

Returns:

  • (Time) 


52
53
54
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 52

def alarm_configuration_updated_timestamp
  data[:alarm_configuration_updated_timestamp]
end

#alarm_description ⇒ String

The description of the alarm.

Returns:

  • (String) 


46
47
48
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 46

def alarm_description
  data[:alarm_description]
end

#client ⇒ Client

Returns:



220
221
222
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 220

def client
  @client
end

#comparison_operator ⇒ String

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

Returns:

  • (String) 


179
180
181
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 179

def comparison_operator
  data[:comparison_operator]
end

#data ⇒ Types::MetricAlarm

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

Returns:



240
241
242
243
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 240

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.



248
249
250
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 248

def data_loaded?
  !!@data
end

#datapoints_to_alarm ⇒ Integer

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

Returns:

  • (Integer) 


165
166
167
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 165

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) 


387
388
389
390
391
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 387

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:



426
427
428
429
430
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 426

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

#dimensions ⇒ Array<Types::Dimension>

The dimensions for the metric associated with the alarm.

Returns:



140
141
142
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 140

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) 


437
438
439
440
441
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 437

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) 


448
449
450
451
452
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 448

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_percentile ⇒ String

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) 


196
197
198
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 196

def evaluate_low_sample_count_percentile
  data[:evaluate_low_sample_count_percentile]
end

#evaluation_periods ⇒ Integer

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

Returns:

  • (Integer) 


159
160
161
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 159

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.



255
256
257
258
259
260
261
262
263
264
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 255

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_statistic ⇒ String

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

Returns:

  • (String) 


134
135
136
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 134

def extended_statistic
  data[:extended_statistic]
end

#insufficient_data_actions ⇒ Array<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>) 


83
84
85
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 83

def insufficient_data_actions
  data[:insufficient_data_actions]
end

#load ⇒ self 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) 


230
231
232
233
234
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 230

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

#metric ⇒ Metric?

Returns:



485
486
487
488
489
490
491
492
493
494
495
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 485

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

#metric_name ⇒ String

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

Returns:

  • (String) 


114
115
116
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 114

def metric_name
  data[:metric_name]
end

#metrics ⇒ Array<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 ReturnData set to true.

Returns:



206
207
208
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 206

def metrics
  data[:metrics]
end

#name ⇒ String Also known as: alarm_name

Returns:

  • (String) 


33
34
35
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 33

def name
  @name
end

#namespace ⇒ String

The namespace of the metric associated with the alarm.

Returns:

  • (String) 


120
121
122
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 120

def namespace
  data[:namespace]
end

#ok_actions ⇒ Array<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>) 


67
68
69
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 67

def ok_actions
  data[:ok_actions]
end

#period ⇒ Integer

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

Returns:

  • (Integer) 


146
147
148
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 146

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) 


476
477
478
479
480
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 476

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

#state_reason ⇒ String

An explanation for the alarm state, in text format.

Returns:

  • (String) 


95
96
97
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 95

def state_reason
  data[:state_reason]
end

#state_reason_data ⇒ String

An explanation for the alarm state, in JSON format.

Returns:

  • (String) 


101
102
103
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 101

def state_reason_data
  data[:state_reason_data]
end

#state_updated_timestamp ⇒ Time

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

Returns:

  • (Time) 


107
108
109
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 107

def state_updated_timestamp
  data[:state_updated_timestamp]
end

#state_value ⇒ String

The state value for the alarm.

Returns:

  • (String) 


89
90
91
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 89

def state_value
  data[:state_value]
end

#statistic ⇒ String

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

Returns:

  • (String) 


127
128
129
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 127

def statistic
  data[:statistic]
end

#threshold ⇒ Float

The value to compare with the specified statistic.

Returns:

  • (Float) 


171
172
173
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 171

def threshold
  data[:threshold]
end

#threshold_metric_id ⇒ String

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) 


213
214
215
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 213

def threshold_metric_id
  data[:threshold_metric_id]
end

#treat_missing_data ⇒ String

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

Returns:

  • (String) 


186
187
188
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 186

def treat_missing_data
  data[:treat_missing_data]
end

#unit ⇒ String

The unit of the metric associated with the alarm.

Returns:

  • (String) 


152
153
154
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 152

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



363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 363

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:



272
273
274
275
276
277
278
279
280
281
 
# File 'gems/aws-sdk-cloudwatch/lib/aws-sdk-cloudwatch/alarm.rb', line 272

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