Class: PgLock::Locket

Inherits:
Object
  • Object
show all
Defined in:
lib/pg_lock/locket.rb

Overview

Holds the logic to aquire a lock and parse if locking was successful

Constant Summary collapse

TRUE_VALUES = 
[true, "t"].freeze

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(connection, lock_args) ⇒ Locket

Returns a new instance of Locket.



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# File 'lib/pg_lock/locket.rb', line 7

def initialize(connection, lock_args)
  self.connection = connection
  self.args       = lock_args
end

Instance Attribute Details

#args ⇒ Object

Returns the value of attribute args.



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# File 'lib/pg_lock/locket.rb', line 6

def args
  @args
end

#connection ⇒ Object

Returns the value of attribute connection.



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# File 'lib/pg_lock/locket.rb', line 6

def connection
  @connection
end

Instance Method Details

#acquired? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_lock/locket.rb', line 22

def acquired?
  TRUE_VALUES.include?(@lock[0]["pg_try_advisory_lock"])
rescue
  false
end

#active? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/pg_lock/locket.rb', line 33

def active?
  query = "    SELECT granted\n    FROM pg_locks\n    WHERE locktype = 'advisory' AND\n    pid = pg_backend_pid() AND\n    mode = 'ExclusiveLock' AND\n    classid = $1 AND\n    objid = $2\n  eos\n\n  result = connection.exec(query, args)\n  return false if result.ntuples == 0\n\n  active = result.getvalue(0,0)\n  TRUE_VALUES.include?(active)\nend\n"

#aquired? ⇒ Boolean

Left the misspelled version of this method for backwards compatibility

Returns:

  • (Boolean) 


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# File 'lib/pg_lock/locket.rb', line 29

def aquired?
  acquired?
end

#lock ⇒ Object 



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# File 'lib/pg_lock/locket.rb', line 12

def lock
  @lock = connection.exec("select pg_try_advisory_lock($1,$2)", args)
  return acquired?
end

#unlock ⇒ Object 



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# File 'lib/pg_lock/locket.rb', line 17

def unlock
  connection.exec("select pg_advisory_unlock($1,$2)", args)
  @lock = false
end