io.lettuce.core.failover.health

Class LagAwareStrategy

java.lang.Object

io.lettuce.core.failover.health.LagAwareStrategy

All Implemented Interfaces:

HealthCheckStrategy, Closeable, AutoCloseable

@Experimental
public class LagAwareStrategy
extends Object
implements HealthCheckStrategy

Health check strategy that uses the Redis Enterprise REST API database availability endpoint.

This strategy uses the /v1/bdbs/<database_id>/availability REST API to verify whether the database is available to perform read and write operations and can respond to queries from client applications.

Health Check Process

1. Resolves the BDB (database) ID by matching the endpoint host against known database endpoints
2. Caches the BDB ID for subsequent health checks to avoid repeated lookups
3. Calls the availability API to check if the database is healthy

Lag-Aware Availability Checks

When LagAwareStrategy.Config.isExtendedCheckEnabled() is true, performs a lag-aware availability check using the extend_check=lag query parameter.

The lag tolerance threshold can be configured via LagAwareStrategy.Config.getAvailabilityLagTolerance() (default: 100ms).

Since:

7.4

Author:

Ivo Gaydazhiev

See Also:

Redis Enterprise Database Availability API

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	LagAwareStrategy.Config

Constructor Summary

Constructors

Constructor and Description
LagAwareStrategy(LagAwareStrategy.Config config)
LagAwareStrategy(LagAwareStrategy.Config config, HttpClient httpClient)

Method Summary

Modifier and Type	Method and Description
void	close() Close any resources used by the health check strategy.
HealthStatus	doHealthCheck(RedisURI endpoint) Perform the health check for the given endpoint.
int	getDelayInBetweenProbes() Get the delay (in milliseconds) between retries for failed health checks.
int	getInterval() Get the interval (in milliseconds) between health checks.
int	getNumProbes() Get the number of probes for health checks to repeat.
ProbingPolicy	getPolicy() Get the policy for health checks.
int	getTimeout() Get the timeout (in milliseconds) for a health check.

Methods inherited from class java.lang.Object

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

Constructor Detail

LagAwareStrategy

public LagAwareStrategy(LagAwareStrategy.Config config)

LagAwareStrategy

public LagAwareStrategy(LagAwareStrategy.Config config,
                        HttpClient httpClient)

Method Detail

getInterval

public int getInterval()

Description copied from interface: HealthCheckStrategy

Get the interval (in milliseconds) between health checks.

Specified by:

getInterval in interface HealthCheckStrategy

Returns:

the interval in milliseconds

getTimeout

public int getTimeout()

Description copied from interface: HealthCheckStrategy

Get the timeout (in milliseconds) for a health check.

Specified by:

getTimeout in interface HealthCheckStrategy

Returns:

the timeout in milliseconds

getNumProbes

public int getNumProbes()

Description copied from interface: HealthCheckStrategy

Get the number of probes for health checks to repeat.

Specified by:

getNumProbes in interface HealthCheckStrategy

Returns:

the number of probes

getPolicy

public ProbingPolicy getPolicy()

Description copied from interface: HealthCheckStrategy

Get the policy for health checks.

Specified by:

getPolicy in interface HealthCheckStrategy

Returns:

the policy

getDelayInBetweenProbes

public int getDelayInBetweenProbes()

Description copied from interface: HealthCheckStrategy

Get the delay (in milliseconds) between retries for failed health checks.

Specified by:

getDelayInBetweenProbes in interface HealthCheckStrategy

Returns:

the delay in milliseconds

doHealthCheck

public HealthStatus doHealthCheck(RedisURI endpoint)

Description copied from interface: HealthCheckStrategy

Perform the health check for the given endpoint.

Specified by:

doHealthCheck in interface HealthCheckStrategy

Parameters:

endpoint - the endpoint to check

Returns:

the health status

close

public void close()

Description copied from interface: HealthCheckStrategy

Close any resources used by the health check strategy.

Specified by:

close in interface HealthCheckStrategy

Specified by:

close in interface Closeable

Specified by:

close in interface AutoCloseable