Package io.lettuce.core.failover.health

Health check infrastructure for automatic failover in multi-database Redis connections.

See: Description

Interface Summary

Interface	Description
HealthCheck	Interface for health check operations on a Redis endpoint.
HealthCheckStrategy	Interface for health check strategies.
HealthCheckStrategySupplier	Supplier for health check strategies.
HealthStatusListener	Listener for health status changes.
HealthStatusManager	Manager for health status of Redis endpoints.
ProbingPolicy	Interface for probing policies.
ProbingPolicy.ProbeContext

Class Summary

Class	Description
AbstractHealthCheckStrategy	Abstract base class for health check strategies.
HealthCheckStrategy.Config
HealthCheckStrategy.Config.Builder<T extends HealthCheckStrategy.Config.Builder<T,C>,C extends HealthCheckStrategy.Config>	Base builder for HealthCheckStrategy.Config and its subclasses.
HealthStatusChangeEvent	Event arguments for health status change events.
HealthStatusManagerImpl	Implementation of the HealthStatusManager interface.
LagAwareStrategy	Health check strategy that uses the Redis Enterprise REST API database availability endpoint.
LagAwareStrategy.Config
LagAwareStrategy.Config.Builder	Builder for LagAwareStrategy.Config.
PingStrategy	Health check strategy that uses PING command to check endpoint health.
ProbingPolicy.BuiltIn

Enum Summary

Enum	Description
HealthStatus	Enumeration representing the health status of a database endpoint as determined by the health check service.
ProbingPolicy.Decision

Exception Summary

Exception	Description
RedisRestException	Exception thrown when a Redis REST API operation fails.

Package io.lettuce.core.failover.health Description

Health check infrastructure for automatic failover in multi-database Redis connections.

Health Check Strategies

This package provides a pluggable health check system for monitoring Redis database endpoints. Custom health check strategies can be implemented by extending HealthCheckStrategy.

Built-in Strategies

• PingStrategy - Uses Redis PING command

Example: Custom HTTP Health Check

 
 {
     @code
     public class HttpHealthCheckStrategy extends AbstractHealthCheckStrategy {

         private final String healthCheckUrl;

         public HttpHealthCheckStrategy(Config config, String healthCheckUrl) {
             super(config);
             this.healthCheckUrl = healthCheckUrl;
         }

         @Override
         public HealthStatus doHealthCheck(RedisURI endpoint) {
             try {
                 HttpURLConnection conn = (HttpURLConnection) new URL(healthCheckUrl).openConnection();
                 int code = conn.getResponseCode();
                 conn.disconnect();
                 return (code >= 200 && code < 300) ? HealthStatus.HEALTHY : HealthStatus.UNHEALTHY;
             } catch (Exception e) {
                 return HealthStatus.UNHEALTHY;
             }
         }
 
     }

     // Usage:
     HealthCheckStrategySupplier supplier = (uri, factory) -> new HttpHealthCheckStrategy(HealthCheckStrategy.Config.create(),
             "http://health-endpoint/check");
     DatabaseConfig config = DatabaseConfig.builder(redisURI).healthCheckStrategySupplier(supplier).build();
 }
 

Since:

7.4

Author:

Ali Takavci, Ivo Gaydazhiev