com.netflix.karyon.server.eureka
Class AsyncHealthCheckInvocationStrategy

java.lang.Object
  com.netflix.karyon.server.eureka.AsyncHealthCheckInvocationStrategy

All Implemented Interfaces:

HealthCheckInvocationStrategy

public class AsyncHealthCheckInvocationStrategy
extends java.lang.Object
implements HealthCheckInvocationStrategy

An implementation of HealthCheckInvocationStrategy that calls the underlying HealthCheckHandler asynchronously. If the underlying handler takes more time than configured in the property PropertyNames.HEALTH_CHECK_TIMEOUT_MILLIS, this handler will throw a TimeoutException. The timeout is retrieved using archaius's dynamic properties and hence can be changed at runtime. The default timeout value is as configured by the propertyPropertyNames.HEALTH_CHECK_TIMEOUT_DEFAULT_MILLIS milliseconds.

Threading model

This class uses exactly one thread to perform the health check. There is no queue used for any concurrent health check requests. Any concurrent health check requests blocks (for the configured timeout) and wait for the single execution to finish after which the same result is returned. This is useful in providing an SLA for the healthcheck and does not create a queuing point which may result in unnecessary tuning and memory overheads.

Field Summary

protected static org.slf4j.Logger

logger

Constructor Summary

AsyncHealthCheckInvocationStrategy(HealthCheckHandler healthCheckHandler)

Method Summary

HealthCheckHandler	getHandler() Returns the instance of HealthCheckHandler associated with this strategy.
int	invokeCheck() Invokes the handler associated with this strategy and returns the response.
void	start()
void	stop()

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

logger

protected static final org.slf4j.Logger logger

Constructor Detail

AsyncHealthCheckInvocationStrategy

@Inject
public AsyncHealthCheckInvocationStrategy(HealthCheckHandler healthCheckHandler)

Method Detail

start

@PostConstruct
public void start()

invokeCheck

public int invokeCheck()
                throws java.util.concurrent.TimeoutException

Description copied from interface: HealthCheckInvocationStrategy

Invokes the handler associated with this strategy and returns the response. This method may block waiting for results.
If this strategy supports timeouts, this call must not wait more than the timeout value.

Specified by:

invokeCheck in interface HealthCheckInvocationStrategy

Returns:

The health check result.

Throws:

java.util.concurrent.TimeoutException - If the healthcheck did not return after the stipulated time (governed entirely by this strategy implementation)

getHandler

public HealthCheckHandler getHandler()

Description copied from interface: HealthCheckInvocationStrategy

Returns the instance of HealthCheckHandler associated with this strategy.

Specified by:

getHandler in interface HealthCheckInvocationStrategy

Returns:

The instance of HealthCheckHandler associated with this strategy.

stop

public void stop()
          throws java.lang.InterruptedException

Throws:

java.lang.InterruptedException