Class: Hiera::Backend::Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/hiera/backend/cloudformation_backend.rb

Overview

Cache class that hides Redis vs. TimedCache implementation

Instance Method Summary collapse

Constructor Details

#initialize(cache_ttl = 60) ⇒ Cache

Returns a new instance of Cache.



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# File 'lib/hiera/backend/cloudformation_backend.rb', line 25

def initialize(cache_ttl = 60)
  @cache_ttl = cache_ttl

  if Config.include?(:cloudformation) && !Config[:cloudformation].nil?
    if Config[:cloudformation].include?(:redis_host)
      @redis_host = Config[:cloudformation][:redis_host]
    end

    if Config[:cloudformation].include?(:redis_port)
      @redis_port = Config[:cloudformation][:redis_port]
    else
      @redis_port = 6379
    end

    if Config[:cloudformation].include?(:redis_db)
      @redis_db = Config[:cloudformation][:redis_db]
    else
      @redis_db = 0
    end
  end

  if @redis_host
    @redis = Redis.new(:host => @redis_host, :port => @redis_port, :db => @redis_db)
  else
    @timedcache = TimedCache.new
  end
end

Instance Method Details

#format_key(key) ⇒ Object

If key is Enumerable convert to a json string



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# File 'lib/hiera/backend/cloudformation_backend.rb', line 88

def format_key(key)
  if key.is_a? Enumerable
    key.to_json
  else
    key
  end
end

#format_value(value) ⇒ Object

Marshal values into sensible JSON form, assumes all arrays contain values of same type



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# File 'lib/hiera/backend/cloudformation_backend.rb', line 97

def format_value(value)
  if value.is_a? Array
    if value.first.is_a? AWS::CloudFormation::StackOutput
      stack_outputs = value.collect do |stack_output|
        {
          :description => stack_output.description,
          :key => stack_output.key,
          :value => stack_output.value
        }
      end
      JSON.generate(stack_outputs)
    else
      JSON.generate(value)
    end
  elsif value.is_a? Hash
    JSON.generate(value)
  else
    value
  end
end

#get(key) ⇒ Object 



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# File 'lib/hiera/backend/cloudformation_backend.rb', line 53

def get(key)
  formatted_key = format_key(key)

  if @redis
    Hiera.debug("Attempting to fetch #{formatted_key} from Redis")
    result = @redis.get(formatted_key)
  else
    Hiera.debug("Attempting to fetch #{formatted_key} from TimedCache")
    result = @timedcache.get formatted_key
  end

  JSON.parse(result) unless result.nil?
end

#put(key, value) ⇒ Object 



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# File 'lib/hiera/backend/cloudformation_backend.rb', line 67

def put(key, value)
  formatted_key = format_key(key)
  formatted_value = format_value(value)

  if @redis
    if @cache_ttl < 1
      Hiera.debug("Attempting to set #{formatted_key} in Redis")
      @redis.set(formatted_key, formatted_value)
    else
      Hiera.debug("Attempting to setex #{formatted_key} in Redis with TTL of #{@cache_ttl}")
      @redis.setex(formatted_key, @cache_ttl, formatted_value)
    end
  else
    Hiera.debug("Attempting to set #{formatted_key} in TimedCache with TTL of #{@cache_ttl}")
    @timedcache.put(formatted_key, formatted_value, @cache_ttl)
  end

  formatted_value
end