Releases

v0.24.0

• Add support for health check failure metrics.

v0.23.0

Add support for NOTIFY_LOG for Kubernetes readiness probes.

You may specify a NOTIFY_LOG environment variable to enable readiness logging to a log file. This can be used for Kubernetes readiness probes, e.g.

containers:
	- name: falcon
		env:
			- name: NOTIFY_LOG
				value: "/tmp/notify.log"
		command: ["falcon", "host"]
		readinessProbe:
			exec:
				command: ["sh", "-c", "grep -q '\"ready\":true' /tmp/notify.log"]
			initialDelaySeconds: 5
			periodSeconds: 5
			failureThreshold: 12

v0.21.0

• Use SIGKILL/Thread#kill when the health check fails. In some cases, SIGTERM may not be sufficient to terminate a process because the signal can be ignored or the process may be in an uninterruptible state.

v0.20.1

• Fix compatibility between class Async::Container::Hybrid and the health check.
• Async::Container::Generic#initialize passes unused arguments through to class Async::Container::Group.

v0.20.0

• Improve container signal handling reliability by using Thread.handle_interrupt except at known safe points.
• Improved logging when child process fails and container startup.

Add health_check_timeout for detecting hung processes.

In order to detect hung processes, a health_check_timeout can be specified when spawning children workers. If the health check does not complete within the specified timeout, the child process is killed.

require "async/container"

container = Async::Container.new

container.run(count: 1, restart: true, health_check_timeout: 1) do |instance|
	while true
		# This example will fail sometimes:
		sleep(0.5 + rand)
		instance.ready!
	end
end

container.wait

If the health check does not complete within the specified timeout, the child process is killed:

 3.01s     warn: Async::Container::Forked [oid=0x1340] [ec=0x1348] [pid=27100] [2025-02-20 13:24:55 +1300]
               | Child failed health check!
               | {
               |   "child": {
               |     "name": "Unnamed",
               |     "pid": 27101,
               |     "status": null
               |   },
               |   "age": 1.0612829999881797,
               |   "health_check_timeout": 1
               | }