Module: Philiprehberger::Scheduler::LeaderElection

Included in:
Philiprehberger::Scheduler
Defined in:
lib/philiprehberger/scheduler/leader_election.rb

Instance Method Summary collapse

Instance Method Details

#acquire_leadership ⇒ Object 



17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
 
# File 'lib/philiprehberger/scheduler/leader_election.rb', line 17

def acquire_leadership
  return false unless @leader_lock_path

  @leader_lock_file = File.open(@leader_lock_path, File::RDWR | File::CREAT)
  if @leader_lock_file.flock(File::LOCK_EX | File::LOCK_NB)
    @leader_lock_file.truncate(0)
    @leader_lock_file.write("#{Process.pid}\n")
    @leader_lock_file.flush
    @is_leader = true
    true
  else
    @leader_lock_file.close
    @leader_lock_file = nil
    @is_leader = false
    false
  end
rescue Errno::ENOENT, Errno::EACCES
  @is_leader = false
  false
end

#enable_leader_election(lock_path:) ⇒ Object 



6
7
8
9
10
11
 
# File 'lib/philiprehberger/scheduler/leader_election.rb', line 6

def enable_leader_election(lock_path:)
  @leader_lock_path = lock_path
  @leader_lock_file = nil
  @is_leader = false
  self
end

#leader? ⇒ Boolean

Returns:

  • (Boolean) 


13
14
15
 
# File 'lib/philiprehberger/scheduler/leader_election.rb', line 13

def leader?
  @is_leader == true
end

#release_leadership ⇒ Object 



38
39
40
41
42
43
44
45
46
47
 
# File 'lib/philiprehberger/scheduler/leader_election.rb', line 38

def release_leadership
  return unless @leader_lock_file

  @leader_lock_file.flock(File::LOCK_UN)
  @leader_lock_file.close
  @leader_lock_file = nil
  @is_leader = false
rescue IOError
  @is_leader = false
end