Module: Wurk::Health

Defined in:
lib/wurk/health.rb

Overview

Thin HTTP listener for k8s liveness/readiness probes. Optional, off by default — opt in with config.health_check(port: 7433) or WURK_HEALTH_PORT=7433, then scrape GET /metrics on that port. Mounting Wurk::Engine does not expose Prometheus metrics: this deliberate separation keeps internal metrics off the host application's HTTP surface so access can be restricted independently on the dedicated listener port.

Endpoints:

* GET /live  → 200 until the Launcher is shutting down; quiet stays 200.
* GET /ready → 200 only when Redis is reachable AND the heartbeat has
             fired within `ready_window` seconds AND, inside a swarm
             child, enough of the swarm's children have (see
             Health::Fleet). 503 otherwise.
* GET /metrics → Prometheus text exposition (Wurk::Metrics::Prometheus).
             On whenever the listener is; `metrics: false` in
             `:health_check_options` turns it into a 404.

Anything else returns 404 JSON.

The server uses a raw TCPServer, one accept thread and a short-lived thread per connection (bounded, deadline-capped). No Rack, no dependencies — it lives inside every worker process where Rails may or may not exist (standalone CLI, Embedded, swarm child). Bound to a dedicated port so it does not collide with the host application's HTTP.

Spec: docs/target/sidekiq-ent.md §7.1.2 (config.health_check).

Defined Under Namespace

Classes: Fleet, Server

Constant Summary collapse

DEFAULT_PORT = 
7433
DEFAULT_BIND = 
'0.0.0.0'
DEFAULT_READY_WINDOW = 
30
JSON_TYPE = 
'application/json'

Class Attribute Summary collapse

Class Method Summary collapse

Class Attribute Details

.fleet_size ⇒ Object

Children the swarm was configured with, set by Swarm::ChildBoot inside each child (inherited from nowhere: the parent never runs a listener). nil outside a swarm child — standalone and embedded processes are a fleet of one and /ready judges them on their own heartbeat alone.



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# File 'lib/wurk/health.rb', line 43

def fleet_size
  @fleet_size
end

.swarm_counters ⇒ Object

The swarm parent's Swarm::RestartCounters, likewise set by ChildBoot; nil outside a swarm child.



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# File 'lib/wurk/health.rb', line 47

def swarm_counters
  @swarm_counters
end

Class Method Details

.json(status, **extra) ⇒ Object 



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# File 'lib/wurk/health.rb', line 65

def json(status, **extra)
  ::JSON.generate({ status: status }.merge(extra))
end

.options_from_env(env = ENV) ⇒ Object

WURK_HEALTH_PORT turns the listener on from the environment, so whoever owns the deployment manifest can add a probe without an application change. config.health_check wins when both are set. A bad value raises: a probe silently not listening would restart the pod forever instead.



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# File 'lib/wurk/health.rb', line 53

def options_from_env(env = ENV)
  raw = env['WURK_HEALTH_PORT'].to_s.strip
  return nil if raw.empty?

  port = Integer(raw, 10)
  raise ArgumentError unless port.between?(0, 65_535)

  { port: port }
rescue ArgumentError
  raise ArgumentError, "WURK_HEALTH_PORT must be a port number (got #{raw.inspect})"
end