Class: LambdaLoadout::AlarmConfig

Inherits:
Object
  • Object
show all
Defined in:
lib/lambda_loadout/errors.rb

Overview

Alarm configuration helper

Helps define CloudWatch Alarms for metrics created via EMF. Note: This generates CloudFormation/SAM template snippets, actual alarm creation should be done via IaC (CloudFormation, Terraform, etc.)

Examples:

Generate alarm configuration

alarm = LambdaLoadout::AlarmConfig.new(
  metric_name: "LambdaError",
  namespace: "MyApp",
  threshold: 1,
  evaluation_periods: 1
)

puts alarm.to_cloudformation

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(metric_name:, namespace:, threshold: 1, statistic: 'Sum', evaluation_periods: 1, period: 60, comparison_operator: 'GreaterThanOrEqualToThreshold') ⇒ AlarmConfig

Initialize alarm configuration

Parameters:

  • metric_name (String) —

    CloudWatch metric name

  • namespace (String) —

    CloudWatch metric namespace

  • threshold (Numeric) (defaults to: 1) —

    Alarm threshold

  • statistic (String) (defaults to: 'Sum') —

    Statistic type (Sum, Average, Maximum, etc.)

  • evaluation_periods (Integer) (defaults to: 1) —

    Number of periods to evaluate

  • period (Integer) (defaults to: 60) —

    Period in seconds

  • comparison_operator (String) (defaults to: 'GreaterThanOrEqualToThreshold') —

    Comparison operator



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# File 'lib/lambda_loadout/errors.rb', line 125

def initialize(
  metric_name:,
  namespace:,
  threshold: 1,
  statistic: 'Sum',
  evaluation_periods: 1,
  period: 60,
  comparison_operator: 'GreaterThanOrEqualToThreshold'
)
  @metric_name = metric_name
  @namespace = namespace
  @threshold = threshold
  @statistic = statistic
  @evaluation_periods = evaluation_periods
  @period = period
  @comparison_operator = comparison_operator
end

Instance Attribute Details

#comparison_operator ⇒ Object (readonly)

Returns the value of attribute comparison_operator.



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# File 'lib/lambda_loadout/errors.rb', line 113

def comparison_operator
  @comparison_operator
end

#evaluation_periods ⇒ Object (readonly)

Returns the value of attribute evaluation_periods.



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# File 'lib/lambda_loadout/errors.rb', line 113

def evaluation_periods
  @evaluation_periods
end

#metric_name ⇒ Object (readonly)

Returns the value of attribute metric_name.



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# File 'lib/lambda_loadout/errors.rb', line 113

def metric_name
  @metric_name
end

#namespace ⇒ Object (readonly)

Returns the value of attribute namespace.



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# File 'lib/lambda_loadout/errors.rb', line 113

def namespace
  @namespace
end

#period ⇒ Object (readonly)

Returns the value of attribute period.



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# File 'lib/lambda_loadout/errors.rb', line 113

def period
  @period
end

#statistic ⇒ Object (readonly)

Returns the value of attribute statistic.



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# File 'lib/lambda_loadout/errors.rb', line 113

def statistic
  @statistic
end

#threshold ⇒ Object (readonly)

Returns the value of attribute threshold.



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# File 'lib/lambda_loadout/errors.rb', line 113

def threshold
  @threshold
end

Instance Method Details

#to_cloudformation(alarm_name: "#{metric_name}Alarm", sns_topic_arn: nil, dimensions: {}) ⇒ String

Generate CloudFormation YAML for alarm

Parameters:

  • alarm_name (String) (defaults to: "#{metric_name}Alarm") —

    CloudFormation logical name

  • sns_topic_arn (String) (defaults to: nil) —

    SNS topic ARN for notifications (optional)

  • dimensions (Hash) (defaults to: {}) —

    Metric dimensions

Returns:

  • (String) —

    CloudFormation YAML snippet



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# File 'lib/lambda_loadout/errors.rb', line 149

def to_cloudformation(alarm_name: "#{metric_name}Alarm", sns_topic_arn: nil, dimensions: {})
  cf = {
    alarm_name => {
      'Type' => 'AWS::CloudWatch::Alarm',
      'Properties' => {
        'AlarmName' => alarm_name,
        'AlarmDescription' => "Alarm for #{metric_name} in #{namespace}",
        'MetricName' => metric_name,
        'Namespace' => namespace,
        'Statistic' => statistic,
        'Period' => period,
        'EvaluationPeriods' => evaluation_periods,
        'Threshold' => threshold,
        'ComparisonOperator' => comparison_operator,
        'TreatMissingData' => 'notBreaching'
      }
    }
  }

  # Add dimensions if provided
  unless dimensions.empty?
    dims = dimensions.map { |k, v| { 'Name' => k.to_s, 'Value' => v.to_s } }
    cf[alarm_name]['Properties']['Dimensions'] = dims
  end

  # Add SNS notification if provided
  cf[alarm_name]['Properties']['AlarmActions'] = [sns_topic_arn] if sns_topic_arn

  require 'yaml'
  YAML.dump(cf)
end

#to_terraform(resource_name: metric_name.downcase, sns_topic_arn: nil, dimensions: {}) ⇒ String

Generate Terraform HCL for alarm

Parameters:

  • resource_name (String) (defaults to: metric_name.downcase) —

    Terraform resource name

  • sns_topic_arn (String) (defaults to: nil) —

    SNS topic ARN for notifications (optional)

  • dimensions (Hash) (defaults to: {}) —

    Metric dimensions

Returns:

  • (String) —

    Terraform HCL snippet



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# File 'lib/lambda_loadout/errors.rb', line 187

def to_terraform(resource_name: metric_name.downcase, sns_topic_arn: nil, dimensions: {})
  hcl = <<~HCL
    resource "aws_cloudwatch_metric_alarm" "#{resource_name}" {
      alarm_name          = "#{resource_name}"
      alarm_description   = "Alarm for #{metric_name} in #{namespace}"
      comparison_operator = "#{comparison_operator}"
      evaluation_periods  = #{evaluation_periods}
      metric_name         = "#{metric_name}"
      namespace           = "#{namespace}"
      period              = #{period}
      statistic           = "#{statistic}"
      threshold           = #{threshold}
      treat_missing_data  = "notBreaching"
  HCL

  # Add dimensions if provided
  unless dimensions.empty?
    hcl += "\n  dimensions = {\n"
    dimensions.each do |k, v|
      hcl += "    #{k} = \"#{v}\"\n"
    end
    hcl += "  }\n"
  end

  # Add SNS notification if provided
  hcl += "\n  alarm_actions = [\"#{sns_topic_arn}\"]\n" if sns_topic_arn

  hcl += "}\n"
  hcl
end