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本文主要研究一下redis的HealthIndicator

RedisHealthIndicator

spring-boot-actuator-2.0.4.RELEASE-sources.jar!/org/springframework/boot/actuate/redis/RedisHealthIndicator.java

public class RedisHealthIndicator extends AbstractHealthIndicator {

    static final String VERSION = "version";

    static final String REDIS_VERSION = "redis_version";

    private final RedisConnectionFactory redisConnectionFactory;

    public RedisHealthIndicator(RedisConnectionFactory connectionFactory) {
        super("Redis health check failed");
        Assert.notNull(connectionFactory, "ConnectionFactory must not be null");
        this.redisConnectionFactory = connectionFactory;
    }

    @Override
    protected void doHealthCheck(Health.Builder builder) throws Exception {
        RedisConnection connection = RedisConnectionUtils
                .getConnection(this.redisConnectionFactory);
        try {
            if (connection instanceof RedisClusterConnection) {
                ClusterInfo clusterInfo = ((RedisClusterConnection) connection)
                        .clusterGetClusterInfo();
                builder.up().withDetail("cluster_size", clusterInfo.getClusterSize())
                        .withDetail("slots_up", clusterInfo.getSlotsOk())
                        .withDetail("slots_fail", clusterInfo.getSlotsFail());
            }
            else {
                Properties info = connection.info();
                builder.up().withDetail(VERSION, info.getProperty(REDIS_VERSION));
            }
        }
        finally {
            RedisConnectionUtils.releaseConnection(connection,
                    this.redisConnectionFactory);
        }
    }

}

• 这里判断是否是cluster，如果是则调用clusterGetClusterInfo，否则调用info方法

RedisReactiveHealthIndicator

spring-boot-actuator-2.0.4.RELEASE-sources.jar!/org/springframework/boot/actuate/redis/RedisReactiveHealthIndicator.java

public class RedisReactiveHealthIndicator extends AbstractReactiveHealthIndicator {

    private final ReactiveRedisConnectionFactory connectionFactory;

    public RedisReactiveHealthIndicator(
            ReactiveRedisConnectionFactory connectionFactory) {
        this.connectionFactory = connectionFactory;
    }

    @Override
    protected Mono<Health> doHealthCheck(Health.Builder builder) {
        ReactiveRedisConnection connection = this.connectionFactory
                .getReactiveConnection();
        return connection.serverCommands().info().map((info) -> up(builder, info))
                .doFinally((signal) -> connection.close());
    }

    private Health up(Health.Builder builder, Properties info) {
        return builder.up().withDetail(RedisHealthIndicator.VERSION,
                info.getProperty(RedisHealthIndicator.REDIS_VERSION)).build();
    }

}

• 采用lettuce的话，启用的是RedisReactiveHealthIndicator，这里调用info方法，不过这个方法返回的属性有点多，大约有83个

小结

redis的HealthIndicator分为RedisHealthIndicator以及RedisReactiveHealthIndicator。如果底层client采用的是lettuce，则使用的是reactive版本。其health检测方法，就是调用info命令。

doc

• 6.2.2. ReactiveRedisConnection and ReactiveRedisConnectionFactory