Class: MysqlGetlock

Inherits:
Object
  • Object
show all
Defined in:
lib/mysql_getlock.rb,
lib/mysql_getlock/version.rb

Defined Under Namespace

Classes: Error, LockError

Constant Summary collapse

TIMEOUT =

inifinity

-1 # inifinity
PSEUDO_INFINITE_TIMEOUT =

for < 5.5.8

4294967295
VERSION = 
"0.2.3"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(mysql2:, key:, logger: nil, timeout: TIMEOUT) ⇒ MysqlGetlock

Returns a new instance of MysqlGetlock.



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# File 'lib/mysql_getlock.rb', line 13

def initialize(mysql2:, key:, logger: nil, timeout: TIMEOUT)
  self.mysql2 = mysql2
  set_key(key)
  set_logger(logger)
  set_timeout(timeout)
end

Instance Attribute Details

#key ⇒ Object (readonly)

Returns the value of attribute key.



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# File 'lib/mysql_getlock.rb', line 5

def key
  @key
end

#logger ⇒ Object (readonly)

Returns the value of attribute logger.



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# File 'lib/mysql_getlock.rb', line 5

def logger
  @logger
end

#mysql2 ⇒ Object

Returns the value of attribute mysql2.



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# File 'lib/mysql_getlock.rb', line 5

def mysql2
  @mysql2
end

#timeout ⇒ Object (readonly)

Returns the value of attribute timeout.



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# File 'lib/mysql_getlock.rb', line 5

def timeout
  @timeout
end

Instance Method Details

#lock ⇒ Object 



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# File 'lib/mysql_getlock.rb', line 29

def lock
  _lock(@timeout)
end

#locked? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mysql_getlock.rb', line 57

def locked?
  results = mysql2.query(%Q[select is_used_lock('#{key}')], as: :array)
  !!results.to_a.first.first
end

#self_locked? ⇒ Boolean

return true if locked by myself

Returns:

  • (Boolean) 


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# File 'lib/mysql_getlock.rb', line 63

def self_locked?
  results = mysql2.query(%Q[select is_used_lock('#{key}')], as: :array)
  lock_id = results.to_a.first.first
  return nil if lock_id.nil?
  results = mysql2.query(%Q[select connection_id()], as: :array)
  self_id = results.to_a.first.first
  self_id == lock_id
end

#synchronize(&block) ⇒ Object

Raises:



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# File 'lib/mysql_getlock.rb', line 72

def synchronize(&block)
  raise LockError unless lock
  begin
    yield
  ensure
    unlock
  end
end

#try_lock ⇒ Object 



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# File 'lib/mysql_getlock.rb', line 33

def try_lock
  _lock(0)
end

#unlock ⇒ Object 



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# File 'lib/mysql_getlock.rb', line 37

def unlock
  if !multiple_lockable? and (current_session_key and current_session_key != key)
    raise Error, "get_lock() was issued for another key '#{current_session_key}', please unlock it beforehand"
  end

  results = mysql2.query(%Q[select release_lock('#{key}')], as: :array)
  release_current_session_key
  case results.to_a.first.first
  when 1
    logger.info { "#{log_head}Released a mysql lock '#{key}'" } if logger
    true
  when 0
    logger.info { "#{log_head}Failed to release a mysql lock since somebody else locked '#{key}'" } if logger
    false
  else # nil
    logger.info { "#{log_head}Mysql lock did not exist '#{key}'" } if logger
    true
  end
end