Class: DBLock::Lock

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

Class Method Summary collapse

Class Method Details

.get(name, timeout = 0) ⇒ Object 



6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
 
# File 'lib/db_lock.rb', line 6

def get(name, timeout=0)
  timeout = timeout.to_i # catches nil
  timeout = 0 if timeout < 0
  raise "Invalid lock name: #{name.inspect}" if name.empty?
  raise AlreadyLocked.new("Already lock in progress") if locked?

  name = prefixed_lock_name(name)

  sql = ActiveRecord::Base.send(:sanitize_sql_array, ["SELECT GET_LOCK(?, ?)", name, timeout])
  lock = ActiveRecord::Base.connection.execute(sql)
  if @locked = (lock and lock.first and lock.first[0] == 1)
    yield
  else
    raise AlreadyLocked.new("Unable to obtain lock '#{name}' within #{timeout} seconds") unless locked?
  end
ensure
  if locked?
    sql = ActiveRecord::Base.send(:sanitize_sql_array, ["SELECT RELEASE_LOCK(?)", name])
    ActiveRecord::Base.connection.execute(sql)
  end
  @locked = false
end

.locked? ⇒ Boolean

Returns:

  • (Boolean) 


29
30
31
 
# File 'lib/db_lock.rb', line 29

def locked?
  @locked ||= false
end