Module: KicksLiveness::ContainerGeneration Private

Defined in:
lib/kicks_liveness/heartbeat.rb

Overview

This module is part of a private API. You should avoid using this module if possible, as it may be removed or be changed in the future.

Identifies an ordinary Linux container incarnation shared by the worker and exec probes without writing anything to the marks directory. This assumes the container owns PID 1; shared and host PID namespaces are documented as unsupported in docs/LIMITATIONS.md.

Class Method Summary collapse

Class Method Details

.current ⇒ String?

This method is part of a private API. You should avoid using this method if possible, as it may be removed or be changed in the future.

Returns current private-PID Linux container incarnation, or nil when procfs does not expose one.

Returns:

  • (String, nil) —

    current private-PID Linux container incarnation, or nil when procfs does not expose one



13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
 
# File 'lib/kicks_liveness/heartbeat.rb', line 13

def current
  mount_namespace = File.readlink('/proc/self/ns/mnt')
  stat = File.read('/proc/1/stat')
  closing_parenthesis = stat.rindex(') ')
  return unless closing_parenthesis

  # After the command in parentheses, field 3 (`state`) is index 0. Process
  # start time is field 22, therefore index 19 in this tail.
  started_at = stat[(closing_parenthesis + 2)..].split[19]
  return unless started_at && Integer(started_at).positive?

  "#{mount_namespace}:#{started_at}"
rescue StandardError
  nil
end