Class: RightScale::Dispatcher::Dispatched

Inherits:
Object
  • Object
show all
Defined in:
lib/right_agent/dispatcher.rb

Overview

Cache for requests that have been dispatched recently This cache is intended for use in checking for duplicate requests

Constant Summary collapse

MAX_AGE =

Maximum number of seconds to retain a dispatched request in cache This must be greater than the maximum possible retry timeout to avoid duplicate execution of a request

12 * 60 * 60

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Dispatched

Initialize cache



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# File 'lib/right_agent/dispatcher.rb', line 41

def initialize
  @cache = {}
  @lru = []
end

Instance Method Details

#fetch(token) ⇒ Object

Fetch request

Parameters

token(String)

Generated message identifier

Return

(Boolean)

true if request has been dispatched, otherwise false



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# File 'lib/right_agent/dispatcher.rb', line 73

def fetch(token)
  if @cache[token]
    @cache[token] = Time.now.to_i
    @lru.push(@lru.delete(token))
  end
end

#size ⇒ Object

Get cache size

Return

(Integer)

Number of cache entries



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# File 'lib/right_agent/dispatcher.rb', line 84

def size
  @cache.size
end

#stats ⇒ Object

Get cache statistics

Return

stats(Hash|nil)

Current statistics, or nil if cache empty

“total”(Integer)

Total number in cache, or nil if none

“oldest”(Integer)

Number of seconds since oldest cache entry created or updated

“youngest”(Integer)

Number of seconds since youngest cache entry created or updated



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# File 'lib/right_agent/dispatcher.rb', line 95

def stats
  if size > 0
    {
      "total" => size,
      "oldest age" => size > 0 ? Time.now.to_i - @cache[@lru.first] : 0,
      "youngest age" => size > 0 ? Time.now.to_i - @cache[@lru.last] : 0
    }
  end
end

#store(token) ⇒ Object

Store dispatched request token in cache

Parameters

token(String)

Generated message identifier

Return

true

Always return true



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# File 'lib/right_agent/dispatcher.rb', line 53

def store(token)
  now = Time.now.to_i
  if @cache.has_key?(token)
    @cache[token] = now
    @lru.push(@lru.delete(token))
  else
    @cache[token] = now
    @lru.push(token)
    @cache.delete(@lru.shift) while (now - @cache[@lru.first]) > MAX_AGE
  end
  true
end