Class: MemCache

Inherits:
Object show all
Defined in:
lib/extensions/memcache.rb

Instance Method Summary collapse

Constructor Details

#initialize(servers = nil, options = {}) ⇒ MemCache

Returns a new instance of MemCache.



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# File 'lib/extensions/memcache.rb', line 75

def initialize(servers=nil, options={})
  @servers = env_servers || servers || 'localhost:11211'
  @options = {:expires_in => 0}.merge(options)
  self.extend(Dalli::Client::MemcacheClientCompatibility) if Dalli::Client.compatibility_mode
end

Instance Method Details

#acquire_lock(key) ⇒ Object 



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# File 'lib/extensions/memcache.rb', line 89

def acquire_lock key
  @locks ||= {}
  return true if has_lock? key

  # Keep trying to add the key to memcache
  # Add returns false if the key is already in memcache
  # Add is our test-and-set operation
  while !add lock_key(key), 1
    # We didn't get the lock, keep trying till we do
    Thread.pass
  end
  @locks[key] = 1
end

#has_lock?(key) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/extensions/memcache.rb', line 110

def has_lock? key
  @locks[key].present?
end

#lock_and_set(key, value, expiry = 0, raw = false) ⇒ Object 



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# File 'lib/extensions/memcache.rb', line 83

def lock_and_set key, value, expiry = 0, raw = false
  acquire_lock key
  set key, value, expiry, raw
  release_lock key
end

#lock_key(name) ⇒ Object 



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# File 'lib/extensions/memcache.rb', line 114

def lock_key name
  "LOCK-#{@name}"
end

#release_lock(key) ⇒ Object 



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# File 'lib/extensions/memcache.rb', line 103

def release_lock key
  if has_lock? key
    delete lock_key(key)
    @locks.delete key
  end
end