Module: RailsPodKit::Health

Defined in:
lib/rails_pod_kit/health.rb

Overview

Opinionated health-monitor-rails configuration for a Rails pod's probe endpoint. One call from an initializer:

RailsPodKit::Health.install!(
redis:   { url: ENV['REDIS_URL'] },
sidekiq: { queue_size: 200, latency: 10.minutes }
)

gives the app a /healthz endpoint checking database (health_monitor's default), cache and (optionally) Redis and Sidekiq — suitable as a k8s startup probe. For liveness/readiness, probe /healthz?providers[]=none to short-circuit the dependency checks once the pod is live, so a transient Redis hiccup doesn't restart the app. Same trick for a manual basic check:

curl '/healthz?providers[]=none' -H 'Accept: application/json'

The Redis connection is injected by the host — the gem never reads REDIS_URL or makes TLS decisions.

Class Method Summary collapse

Class Method Details

.auto_mount? ⇒ Boolean

Read by the Railtie's deferred routes block: true only once install! ran (initializers run before the route set is drawn) and mount wasn't opted out.

Returns:

  • (Boolean) 


86
87
88
 
# File 'lib/rails_pod_kit/health.rb', line 86

def auto_mount?
  !!@auto_mount
end

.build_connection(redis) ⇒ Object 



90
91
92
93
94
95
 
# File 'lib/rails_pod_kit/health.rb', line 90

def build_connection(redis)
  return redis unless redis.is_a?(Hash)

  require 'redis'
  ::Redis.new(**redis)
end

.install!(redis: nil, path: :healthz, sidekiq: nil, silence_controller_log: true, mount: true) ⇒ Object

Configures HealthMonitor with the kit's defaults.

redis: optional Redis connection options hash (same shape the host passes to Sidekiq) or a ready connection object (Redis / ConnectionPool); when given the Redis provider is added. Omit entirely (or pass nil) on hosts with no Redis dependency to get a database + cache only endpoint. path: mount-relative endpoint path (default :healthz). sidekiq: optional thresholds hash; when given the Sidekiq provider is added with the provided queue_size: / latency: overrides (health_monitor defaults apply for missing keys). Omit entirely on hosts without Sidekiq. silence_controller_log: drop the per-probe INFO request logging (default true) — kubelet probes hit the endpoint every few seconds and would drown real request logs. mount: when true (default) the gem's Railtie mounts HealthMonitor::Engine at '/' automatically; pass false to keep route ownership and mount it yourself in config/routes.rb.

Any further host-specific tuning (extra providers, error callback, …) can be done in the block, which receives the HealthMonitor configuration.



57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
 
# File 'lib/rails_pod_kit/health.rb', line 57

def install!(redis: nil, path: :healthz, sidekiq: nil, silence_controller_log: true, mount: true)
  @auto_mount = mount

  HealthMonitor.configure do |config|
    config.path = path
    config.cache

    if redis
      config.redis.configure do |redis_config|
        redis_config.connection = build_connection(redis)
      end
    end

    if sidekiq
      config.sidekiq.configure do |sidekiq_config|
        sidekiq_config.queue_size = sidekiq[:queue_size] if sidekiq[:queue_size]
        sidekiq_config.latency    = sidekiq[:latency]    if sidekiq[:latency]
      end
    end

    yield config if block_given?
  end

  silence_controller_log! if silence_controller_log
end

.silence_controller_log! ⇒ Object

Quiet the engine controller so kubelet probes don't emit an INFO line per hit. Deferred to to_prepare because the engine controller is autoloaded.



99
100
101
102
103
104
105
 
# File 'lib/rails_pod_kit/health.rb', line 99

def silence_controller_log!
  return unless defined?(Rails.application) && Rails.application

  Rails.application.reloader.to_prepare do
    HealthMonitor::HealthController.logger.level = :warn
  end
end