`class HealthChecker`

Performs health checks on endpoints. Called by LoadBalancer's loop. Runs within the caller's reactor; does not spawn tasks or reactors. Only HTTP health checks are supported; gRPC health checks return :unknown.

Definitions

`def initialize(health_checks)`

Initialize health checker

Signature

parameter　health_checks　Array<Hash>: Health check configurations from cluster

Implementation

def initialize(health_checks)
	@health_checks = health_checks
	@endpoints = []
	@cache = {}
end

`def update_endpoints(endpoints)`

Update endpoints (cleans cache for removed endpoints)

Signature

parameter　endpoints　Array<Async::HTTP::Endpoint>: Current endpoints

Implementation

def update_endpoints(endpoints)
	removed = @endpoints - endpoints
	removed.each{|endpoint| @cache.delete(endpoint)}
	@endpoints = endpoints
end

`def check(endpoint)`

Check health of endpoint. Runs in caller's reactor.

Signature

parameter　endpoint　Async::HTTP::Endpoint: Endpoint to check
returns　Symbol: :healthy, :unhealthy, or :unknown

Implementation

def check(endpoint)
	if cached = @cache[endpoint]
		return cached[:status] if Time.now - cached[:time] < 5
	end
	
	status = perform_check(endpoint)
	@cache[endpoint] = {status: status, time: Time.now}
	status
end

`def close`

Close health checker

Implementation

def close
	@cache.clear
end