gitlab-org--gitlab-foss/lib/gitlab/process_management.rb

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# frozen_string_literal: true
module Gitlab
module ProcessManagement
# The signals that should terminate both the master and workers.
TERMINATE_SIGNALS = %i(INT TERM).freeze
# The signals that should simply be forwarded to the workers.
FORWARD_SIGNALS = %i(TTIN USR1 USR2 HUP).freeze
# Traps the given signals and yields the block whenever these signals are
# received.
#
# The block is passed the name of the signal.
#
# Example:
#
# trap_signals(%i(HUP TERM)) do |signal|
# ...
# end
def self.trap_signals(signals)
signals.each do |signal|
trap(signal) do
yield signal
end
end
end
def self.trap_terminate(&block)
trap_signals(TERMINATE_SIGNALS, &block)
end
def self.trap_forward(&block)
trap_signals(FORWARD_SIGNALS, &block)
end
def self.signal(pid, signal)
Process.kill(signal, pid)
true
rescue Errno::ESRCH
false
end
def self.signal_processes(pids, signal)
pids.each { |pid| signal(pid, signal) }
end
# Waits for the given process to complete using a separate thread.
def self.wait_async(pid)
Thread.new do
Process.wait(pid) rescue Errno::ECHILD
end
end
# Returns true if all the processes are alive.
def self.all_alive?(pids)
pids.each do |pid|
return false unless process_alive?(pid)
end
true
end
def self.any_alive?(pids)
pids_alive(pids).any?
end
def self.pids_alive(pids)
pids.select { |pid| process_alive?(pid) }
end
def self.process_alive?(pid)
# Signal 0 tests whether the process exists and we have access to send signals
# but is otherwise a noop (doesn't actually send a signal to the process)
signal(pid, 0)
end
def self.write_pid(path)
File.open(path, 'w') do |handle|
handle.write(Process.pid.to_s)
end
end
end
end