Class: MapRedus::FileSystem

Inherits:
Object
  • Object
show all
Defined in:
lib/mapredus/filesystem.rb

Overview

Manages the book keeping of redis keys and redis usage provides the data storage for process information through redis All interaction with redis should go through this class

Class Method Summary collapse

Class Method Details

.acquire_lock(key) ⇒ Object 



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# File 'lib/mapredus/filesystem.rb', line 60

def self.acquire_lock(key)
  MapRedus.acquire_redis_lock_nonblock( RedisKey.result_cache(key), 60 * 60 )
end

.copy(first_key, second_key) ⇒ Object

Copy the values from one key to a second key

NOTE TODO: currently only works for the redis list data structure but will be extended for arbitrary data types.

NOTE: this does not account for the key being changed during the copy, so should not be used in situations where the first_key value can change during the running of copy.

Examples

FileSystem.copy("key_one", "key_two")

returns true on success false otherwise



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# File 'lib/mapredus/filesystem.rb', line 41

def self.copy(first_key, second_key)
  list_length = storage.llen(first_key)
  list_length.times do |index|
    storage.rpush(second_key, storage.lindex(first_key, index))
  end
  true
end

.has_lock?(key) ⇒ Boolean

Setup locks on results using RedisSupport lock functionality

Examples

FileSystem::has_lock?(key)
# => true or false

Returns true if there’s a lock

Returns:

  • (Boolean) 


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# File 'lib/mapredus/filesystem.rb', line 56

def self.has_lock?(key)
  MapRedus.has_redis_lock?( RedisKey.result_cache(key) ) 
end

.method_missing(method, *args, &block) ⇒ Object 



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# File 'lib/mapredus/filesystem.rb', line 20

def self.method_missing(method, *args, &block)
  if storage.respond_to?(method)
    storage.send(method, *args)
  else
    super
  end
end

.release_lock(key) ⇒ Object 



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# File 'lib/mapredus/filesystem.rb', line 64

def self.release_lock(key)
  MapRedus.release_redis_lock( RedisKey.result_cache(key) )
end

.save(key, value, time = nil) ⇒ Object

Save/Read functions to save/read values for a redis key

Examples

FileSystem.save( key, value )



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# File 'lib/mapredus/filesystem.rb', line 15

def self.save(key, value, time = nil)
  storage.set(key, value)
  storage.expire(key, time) if time
end

.storage ⇒ Object 



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# File 'lib/mapredus/filesystem.rb', line 7

def self.storage
  MapRedus.redis
end