Class: CfnGuardian::Resource::Base

Inherits:
Object
  • Object
show all
Includes:
Logging
Defined in:
lib/cfnguardian/resources/base.rb

Instance Method Summary collapse

Methods included from Logging

colors, included, logger, #logger, logger=

Constructor Details

#initialize(resource, override_group = nil) ⇒ Base

Returns a new instance of Base.



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# File 'lib/cfnguardian/resources/base.rb', line 13

def initialize(resource, override_group = nil)
  @resource = resource
  @override_group = override_group
  @alarms = []
  @events = []
  @checks = []
  @metric_filters = []
  @event_subscriptions = []
end

Instance Method Details

#default_alarms ⇒ Object

Overidden by inherited classes to define default alarms



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# File 'lib/cfnguardian/resources/base.rb', line 24

def default_alarms()
  return @alarms
end

#default_checks ⇒ Object

Overidden by inherited classes to define default checks



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# File 'lib/cfnguardian/resources/base.rb', line 155

def default_checks()
  return @checks
end

#default_event_subscriptions ⇒ Object

Overidden by inherited classes to define default checks



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# File 'lib/cfnguardian/resources/base.rb', line 175

def default_event_subscriptions()
  return @event_subscriptions
end

#default_events ⇒ Object

Overidden by inherited classes to define default events



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# File 'lib/cfnguardian/resources/base.rb', line 145

def default_events()
  return @events
end

#default_metric_filters ⇒ Object

Overidden by inherited classes to define default checks



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# File 'lib/cfnguardian/resources/base.rb', line 165

def default_metric_filters()
  return @metric_filters
end

#get_alarms(group, overides = {}) ⇒ Object 



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# File 'lib/cfnguardian/resources/base.rb', line 28

def get_alarms(group,overides={})
  # deep copying the overrides to preserve its reference before doing any changes to it
  overides = Marshal.load(Marshal.dump(overides))

  # generate default alarms
  default_alarms()

  # override any group properties
  group_overrides = overides.has_key?('GroupOverrides') ? overides['GroupOverrides'] : {}
  overides.delete('GroupOverrides')
  if group_overrides.any?
    @alarms.each do |alarm|
      logger.debug("overriding #{alarm.name} alarm properties for resource #{alarm.resource_id} in resource group #{group} via group overrides") 
      group_overrides.each {|attr,value| update_object(alarm,attr,value)}
    end
  end

  # loop over each override template for the service
  overides.each do |name,properties|       
    # disable default alarms
    if [false].include?(properties)
      alarms = find_alarms(name)
      
      if !alarms.nil?
        alarms.each do |alarm| 
          alarm.enabled = false
          logger.info "disabling alarm '#{name}' for resource #{alarm.resource_id}"
        end
        next
      end
    end

    # continue if the override is in the incorrect format
    unless properties.is_a?(Hash)
      if name != 'Inherit'
        logger.warn "incorrect format for alarm '#{name}'. Should be of type 'Hash', instead got type '#{properties.group}'"
      end
      next
    end

    properties.merge!(group_overrides)

    # Create a new alarm inheriting the defaults of an existing alarm
    if properties.has_key?('Inherit')
      alarm = find_alarm(properties['Inherit'])
      if !alarm.nil?
        logger.debug("creating new alarm #{name} for alarm group #{self.class.to_s.split('::').last} inheriting properties from alarm #{properties['Inherit']}")
        inherited_alarm = alarm.clone
        alarm.name = name
        properties.each {|attr,value| update_object(inherited_alarm,attr,value)}
        @alarms.push(inherited_alarm)
      else
        logger.warn "alarm '#{properties['Inherit']}' doesn't exist and cannot be inherited"
      end
      next
    end
    
    alarms = find_alarms(name)

    if alarms.empty? && !['LogGroup'].any?(group)
      # if the alarm doesn't exist and it's not being inherited from another alarm create a new alarm
      # and is a supported a resource group.
      # unsupported resource groups
      # - LogGroup: this is not required as alarms are defined in the Metric Filters object in the resource group
      resources = @resource.has_key?('Hosts') ? @resource['Hosts'] : [@resource]
      resources.each do |res|
        alarm = Kernel.const_get("CfnGuardian::Models::#{self.class.to_s.split('::').last}Alarm").new(res)
        properties.each {|attr,value| update_object(alarm,attr,value)}
        alarm.name = name
        logger.debug("created new alarm #{alarm.name} for resource #{alarm.resource_id} in resource group #{group}")
        @alarms.push(alarm)
      end
    else
      # if there is an existing alarm update the properties
      alarms.each do |alarm|
        logger.debug("overriding #{alarm.name} alarm properties for resource #{alarm.resource_id} in resource group #{group} via alarm overrides") 
        properties.each {|attr,value| update_object(alarm,attr,value)}
      end
    end
  end
  
  unless @override_group.nil?
    @alarms.each {|a| a.group = @override_group}
  end
  
  @alarms.each do |alarm|
    # String interpolation for alarm dimensions
    unless alarm.dimensions.nil?
      alarm.dimensions.each do |k,v|
        if v.is_a?(String) && v.match?(/^\${Resource::.*[A-Za-z]}$/)
          resource_key = v.tr('${}', '').split('Resource::').last
          if @resource.has_key?(resource_key)
            logger.debug "overriding alarm #{alarm.name} dimension key '#{k}' with value '#{@resource[resource_key]}'" 
            alarm.dimensions[k] = @resource[resource_key]
          end
        end
      end
    end

    # String interpolation for search expressions
    if alarm.search_expression.is_a?(String)
      alarm.search_expression = alarm.search_expression.gsub(/\${Resource::([A-Za-z0-9_]+)}/) do
        resource_key = Regexp.last_match(1)
        if @resource.has_key?(resource_key)
          logger.debug "interpolating search_expression variable '#{resource_key}' with value '#{@resource[resource_key]}' for alarm #{alarm.name}"
          @resource[resource_key]
        else
          "${Resource::#{resource_key}}"
        end
      end
    end
  end

  return @alarms.select{|a| a.enabled}
end

#get_checks ⇒ Object 



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# File 'lib/cfnguardian/resources/base.rb', line 159

def get_checks()
  default_checks()
  return @checks
end

#get_cost ⇒ Object 



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# File 'lib/cfnguardian/resources/base.rb', line 228

def get_cost()
  return @alarms.length * 0.10
end

#get_event_subscriptions(group, overides) ⇒ Object 



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# File 'lib/cfnguardian/resources/base.rb', line 179

def get_event_subscriptions(group, overides)
  # generate default event subscriptions
  default_event_subscriptions()

  # override the defaults
  overides.each do |name, properties|
    event_subscription = find_event_subscriptions(name)

    # disable the event subscription if the value is false
    if [false].include?(properties)
      unless event_subscription.nil?
        event_subscription.enabled = false
        logger.info "Disabling event subscription #{name} for #{group} #{event_subscription.resource_id}"
      end

      next
    end

    # ignore all properties not in a proper format
    next unless properties.is_a?(Hash) 

    # Create a new event subscription by inheriting an existing one
    if properties.has_key?('Inherit')
      inherit_event_subscription = find_event_subscriptions(properties['Inherit'])
      
      if inherit_event_subscription.nil?
        logger.warn "Unable to create #{topic} RDSEventSubscription by inheriting #{properties['Inherit']} as it cannot be found"
        next
      end

      event_subscription = inherit_event_subscription.clone
      event_subscription.enabled = true
      event_subscription.name = name
      @event_subscriptions.push(event_subscription) 
      logger.debug "Inheriting RDSEventSubscription #{properties['Inherit']}"
    end

    if event_subscription.nil?
      event_subscription = Kernel.const_get("CfnGuardian::Models::#{self.class.to_s.split('::').last}EventSubscription").new(@resource)
      event_subscription.name = name
      @event_subscriptions.push(event_subscription) 
    end

    properties.each {|attr,value| update_object(event_subscription,attr,value)}
  end

  return @event_subscriptions.select {|es| es.enabled }
end

#get_events ⇒ Object 



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# File 'lib/cfnguardian/resources/base.rb', line 149

def get_events()
  default_events()
  return @events.select{|e| e.enabled}
end

#get_metric_filters ⇒ Object 



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# File 'lib/cfnguardian/resources/base.rb', line 169

def get_metric_filters()
  default_metric_filters()
  return @metric_filters
end

#resource_exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/cfnguardian/resources/base.rb', line 232

def resource_exists?
  return true
end