28637103998

Committed 03 Jul 2026 03:48AM UTC coverage: 90.399% (-0.2%) from 90.63%

Build # 28637103998

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Hyshmily

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fix: add packaging to gitignore, fix flaky jitter test, update docs references

Signed-off-by: Hyshmily <cxm8607@outlook.com>

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/common/src/main/java/io/github/hyshmily/hotkey/autoconfigure/HotKeyAutoConfiguration.java

/*
 * Copyright 2026 Hyshmily. All Rights Reserved.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package io.github.hyshmily.hotkey.autoconfigure;

import static io.github.hyshmily.hotkey.util.TimeSource.currentTimeMillis;

import com.github.benmanes.caffeine.cache.Cache;
import com.github.benmanes.caffeine.cache.Caffeine;
import com.github.benmanes.caffeine.cache.Expiry;
import io.github.hyshmily.hotkey.HotKey;
import io.github.hyshmily.hotkey.Internal;
import io.github.hyshmily.hotkey.cache.HotKeyCache;
import io.github.hyshmily.hotkey.cache.cachesupport.CacheExpireManager;
import io.github.hyshmily.hotkey.cache.cachesupport.HotKeyCircuitBreaker;
import io.github.hyshmily.hotkey.cache.cachesupport.SingleFlight;
import io.github.hyshmily.hotkey.constants.HotKeyConstants;
import io.github.hyshmily.hotkey.hotkeydetector.HotKeyDetector;
import io.github.hyshmily.hotkey.hotkeydetector.heavykeeper.HeavyKeeper;
import io.github.hyshmily.hotkey.hotkeydetector.heavykeeper.TopK;
import io.github.hyshmily.hotkey.model.CacheEntry;
import io.github.hyshmily.hotkey.reporting.HotKeyReporter;
import io.github.hyshmily.hotkey.rule.RuleMatcher;
import io.github.hyshmily.hotkey.sharding.ClusterHealthView;
import io.github.hyshmily.hotkey.sync.local.CacheSyncPublisher;
import io.github.hyshmily.hotkey.util.version.VersionController;
import java.util.Optional;
import java.util.concurrent.Executor;
import java.util.concurrent.RejectedExecutionException;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;
import lombok.extern.slf4j.Slf4j;
import org.jspecify.annotations.NonNull;
import org.springframework.beans.factory.ObjectProvider;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.boot.autoconfigure.AutoConfiguration;
import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

/**
 * App-side autoconfiguration for the HotKey library.
 *
 * <p>Creates the app-side {@link TopK} detector (HeavyKeeper), L1 Caffeine
 * cache, {@link SingleFlight} deduplication layer, executor, and the
 * primary {@link HotKeyCache} (without Redis version tracking when Redis
 * is absent).
 *
 * <p><b>Condition:</b> this configuration is <em>skipped</em> when the
 * Worker is active ({@code hotkey.worker.enabled=true}). It runs when
 * Worker is disabled or the property is absent.
 */
@Internal
@AutoConfiguration(after = RedisAutoConfiguration.class)
@ConditionalOnProperty(prefix = "hotkey.worker", name = "enabled", havingValue = "false", matchIfMissing = true)
@EnableConfigurationProperties(HotKeyProperties.class)
@Slf4j
public class HotKeyAutoConfiguration {

  /**
   * Create the app-side TopK instance (HeavyKeeper) as a standalone bean.
   *
   * <p>The HeavyKeeper uses a Count-Min Sketch augmented with a minimum-count
   * threshold and exponential decay to track the top-K hottest keys with high
   * accuracy and low memory footprint. Configuration parameters (width, depth,
   * decay, minCount, topK capacity, expelled queue capacity) are read from
   * {@link HotKeyProperties}.
   *
   * @param properties the HotKey configuration properties (never {@code null})
   * @return a new HeavyKeeper TopK instance
   */
  @Bean
  @ConditionalOnMissingBean
  public HeavyKeeper heavyKeeper(HotKeyProperties properties) {
    return new HeavyKeeper(
      properties.getTopK(),
      properties.getWidth(),
      properties.getDepth(),
      properties.getDecay(),
      properties.getMinCount(),
      properties.getExpelledQueueCapacity(),
      properties.getSketchWindowCount()
    );
  }

  /**
   * Create the app-side {@link HotKeyDetector} facade that wraps the HeavyKeeper TopK
   * and schedules periodic decay.
   *
   * <p>The detector provides the primary hot-key detection API ({@code add()}, {@code list()},
   * {@code total()}) and schedules the periodic HeavyKeeper decay using the shared scheduler.
   * This bean is the {@code @Qualifier("hotKeyDetector")} target for injection into
   * {@link HotKeyCache} and other components.
   *
   * @param heavyKeeper      the HeavyKeeper TopK instance (never {@code null})
   * @param hotKeyScheduler  the shared scheduler for periodic tasks (never {@code null})
   * @return a new HotKeyDetector instance
   */
  @Bean
  @ConditionalOnMissingBean
  @SuppressWarnings("SpringJavaInjectionPointsAutowiringInspection")
  public HotKeyDetector hotKeyDetector(
    HeavyKeeper heavyKeeper,
    @Qualifier("hotKeyScheduler") ScheduledExecutorService hotKeyScheduler
  ) {
    return new HotKeyDetector(heavyKeeper, hotKeyScheduler);
  }

  /**
   * Create the SingleFlight deduplication layer for concurrent cache-load requests.
   *
   * <p>When multiple threads request the same key simultaneously (a cache miss), the
   * first caller triggers the load and subsequent callers wait for the same result
   * rather than duplicating the load. Configuration parameters (max in-flight entries,
   * TTL, timeout) are read from {@link HotKeyProperties}.
   *
   * @param properties     the HotKey configuration properties (never {@code null})
   * @param hotKeyExecutor the dedicated HotKey executor for async load execution (never {@code null})
   * @return a new SingleFlight instance
   */
  @Bean
  @ConditionalOnMissingBean
  public SingleFlight singleFlight(HotKeyProperties properties, @Qualifier("hotKeyExecutor") Executor hotKeyExecutor) {
    return new SingleFlight(
      properties.getInflightMaxSize(),
      properties.getInflightTtlSeconds(),
      properties.getInflightTimeoutSeconds(),
      hotKeyExecutor,
      new HotKeyCircuitBreaker(properties.getCircuitBreaker())
    );
  }

  /**
   * Create the soft/hard expiration manager that manages time-based eviction.
   *
   * <p>The soft-expire mechanism triggers an asynchronous refresh when a configurable
   * portion of the TTL has elapsed, serving stale data while fetching a fresh value
   * in the background. The hard-expire is the absolute maximum TTL enforced at the
   * Caffeine level. The refresh pool size limits concurrent background refresh tasks
   * to prevent resource exhaustion under high cache-miss rates.
   *
   * @param hotLocalCache  the L1 Caffeine cache (never {@code null})
   * @param hotKeyExecutor the dedicated HotKey executor for async refresh tasks (never {@code null})
   * @param properties     the HotKey configuration properties (never {@code null})
   * @return a new CacheExpireManager instance
   */
  @Bean
  @ConditionalOnMissingBean
  public CacheExpireManager expireManager(
    Cache<String, Object> hotLocalCache,
    @Qualifier("hotKeyExecutor") Executor hotKeyExecutor,
    HotKeyProperties properties
  ) {
    return new CacheExpireManager(hotLocalCache, hotKeyExecutor, properties, properties.getRefreshMaxPools());
  }

  /**
   * Create the dedicated thread-pool executor for asynchronous cache operations.
   *
   * <p>This executor handles all async operations in the HotKey data path: cache loading
   * via SingleFlight, soft-expiry refresh tasks, and cross-instance broadcast callbacks.
   * Uses a bounded thread pool to limit concurrent AMQP channel usage (RabbitMQ's
   * {@code CachingConnectionFactory} associates channels with platform threads, so
   * unbounded virtual-thread concurrency causes channel-open timeouts). The pool is
   * configured with core/max pool size, bounded queue capacity, and a rejection policy
   * that throws {@link RejectedExecutionException} when the queue is full. On shutdown,
   * in-progress tasks are allowed to complete with a 60-second grace period.
   *
   * @param properties the HotKey configuration properties (never {@code null})
   * @return a configured {@link ThreadPoolTaskExecutor}
   */
  @Bean("hotKeyExecutor")
  @ConditionalOnMissingBean(name = "hotKeyExecutor")
  public Executor hotKeyExecutor(HotKeyProperties properties) {
    ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
    executor.setCorePoolSize(properties.getExecutorCorePoolSize());
    executor.setMaxPoolSize(properties.getExecutorMaxPoolSize());
    executor.setQueueCapacity(properties.getExecutorQueueCapacity());
    executor.setThreadNamePrefix(HotKeyConstants.THREAD_PREFIX_HOTKEY);
    executor.setWaitForTasksToCompleteOnShutdown(true);
    executor.setAwaitTerminationSeconds(60);
    executor.setRejectedExecutionHandler((r, exe) -> {
      log.warn(
        "HotKey executor task rejected: corePool={}, maxPool={}, queueCapacity={}",
        properties.getExecutorCorePoolSize(),
        properties.getExecutorMaxPoolSize(),
        properties.getExecutorQueueCapacity()
      );
      throw new RejectedExecutionException("HotKey executor queue full");
    });
    executor.initialize();
    return executor;
  }

  /**
   * Create the {@link RuleMatcher} for key matching against user-defined rules.
   *
   * <p>This variant is wired with an empty Redis provider and an optional sync
   * publisher, since no {@link StringRedisTemplate} is available in the non-Redis
   * deployment mode. Rules are kept in-memory only and do not survive restarts.
   * When Redis is available, {@link HotKeyRedisAutoConfiguration#ruleMatcher}
   * takes over with Redis persistence.
   *
   * @param publisherProvider optional provider for the cache sync publisher (may be absent)
   * @return a new RuleMatcher instance (in-memory only)
   */
  @Bean
  @ConditionalOnMissingBean({ RuleMatcher.class, StringRedisTemplate.class })
  public RuleMatcher ruleMatcher(ObjectProvider<CacheSyncPublisher> publisherProvider) {
    return new RuleMatcher(Optional.empty(), Optional.ofNullable(publisherProvider.getIfAvailable()));
  }

  /**
   * Create the {@link HotKeyCache} (non-Redis variant).
   *
   * <p>Only active when {@code RedisTemplate} is absent; otherwise
   * {@link HotKeyRedisAutoConfiguration#hotKeyCache} takes over. Creates a
   * {@link VersionController} with an empty Redis provider (falling back to
   * node-local counters) and default ring manager / health view when none are
   * available from the application context.
   *
   * @param hotKeyDetector            the app-side TopK detector (never {@code null})
   * @param hotLocalCache             the L1 Caffeine cache (never {@code null})
   * @param singleFlight              the deduplication layer (never {@code null})
   * @param expireManager             the soft/hard expiration manager (never {@code null})
   * @param syncPublisher             optional cache sync publisher (may be absent)
   * @param hotKeyReporter            optional hot key reporter (may be absent; e.g. in Worker-only mode)
   * @param hotKeyExecutor            the dedicated HotKey executor (never {@code null})
   * @param properties                the HotKey configuration properties (never {@code null})
   * @param ruleMatcher               the rule matcher instance (never {@code null})
   * @param healthViewProvider        provider for the cluster health view (creates default if absent)
   * @return a new HotKeyCache instance with node-local version tracking
   */
  @Bean
  @ConditionalOnMissingBean(type = "org.springframework.data.redis.core.RedisTemplate")
  public HotKeyCache hotKeyCache(
    @Qualifier("hotKeyDetector") HotKeyDetector hotKeyDetector,
    Cache<String, Object> hotLocalCache,
    SingleFlight singleFlight,
    CacheExpireManager expireManager,
    Optional<CacheSyncPublisher> syncPublisher,
    Optional<HotKeyReporter> hotKeyReporter,
    @Qualifier("hotKeyExecutor") Executor hotKeyExecutor,
    HotKeyProperties properties,
    RuleMatcher ruleMatcher,
    ObjectProvider<ClusterHealthView> healthViewProvider
  ) {
    return new HotKeyCache(
      hotKeyDetector,
      hotLocalCache,
      singleFlight,
      expireManager,
      hotKeyExecutor,
      syncPublisher,
      hotKeyReporter,
      ruleMatcher,
      new VersionController(Optional.empty(), properties.getVersionKeyTtlMinutes()),
      properties,
      new ClusterHealthView(
        properties.getExpectedWorkerCount(),
        properties.getHeartbeat().getTimeoutMs(),
        properties.getHeartbeat().getDegradeAfterFailures()
      )
    );
  }

  /**
   * Fallback {@link HotKey} facade bean.
   *
   * <p>Only active when a {@link HotKeyCache} bean exists but no {@link HotKey}
   * has been defined yet. The primary {@link HotKey} creator is
   * {@link HotKeyFacadeAutoConfiguration} — this fallback covers the case where
   * that auto-configuration is excluded or its bean is overridden.
   *
   * @param hotKeyCache    the HotKeyCache instance (never {@code null})
   * @param appHotKeyDetector the app-side TopK detector (never {@code null})
   * @param workerTopKProvider     the Worker-side TopK algorithm (may be {@code null})
   * @return a new HotKey facade instance
   */
  @Bean
  @ConditionalOnBean(HotKeyCache.class)
  @ConditionalOnMissingBean
  public HotKey hotKey(
    HotKeyCache hotKeyCache,
    @Qualifier("hotKeyDetector") HotKeyDetector appHotKeyDetector,
    @Qualifier("workerTopK") ObjectProvider<TopK> workerTopKProvider
  ) {
    return new HotKey(hotKeyCache, appHotKeyDetector, workerTopKProvider.getIfAvailable());
  }

  /**
   * Create the L1 Caffeine cache instance.
   *
   * <p>Time-based expiry operates at the <em>Caffeine</em> level via a custom
   * {@link Expiry} implementation, computing remaining nanoseconds from
   * . Entries with
   * {@code hardExpireAtMs == Long.MAX_VALUE} are purely logical-expiry
   * — Caffeine never evicts them by time; they live until size eviction or
   * manual invalidation. Reads never extend the expiry duration (no read-based
   * refresh), ensuring predictable TTL behavior.
   *
   * <p>The maximum cache size is configured via {@code hotkey.local.local-cache-max-size}
   * (default 1000 entries). Time-based TTL for entries without an explicit hard-expire
   * timestamp defaults to {@code hotkey.local.local-cache-ttl-minutes} (default 5 minutes).
   *
   * @param properties the HotKey configuration properties (never {@code null})
   * @return a configured Caffeine {@link Cache} instance
   */
  @Bean
  @ConditionalOnMissingBean
  public Cache<String, Object> hotLocalCache(HotKeyProperties properties) {
    Caffeine<Object, Object> builder = Caffeine.newBuilder()
      .maximumSize(properties.getLocalCacheMaxSize())
      .expireAfter(
        new Expiry<>() {
          /**
           * Compute the time-to-live for a newly created cache entry.
           * Returns {@link Long#MAX_VALUE} for pure logical-expiry entries
           * (where {@code hardExpireAtMs == Long.MAX_VALUE}); otherwise
           * computes the remaining wall-clock time.
           *
           * @param key              the cache key
           * @param value            the cache value (expected to be a {@link CacheEntry})
           * @param currentTimeNanos the current time in nanoseconds (provided by Caffeine)
           * @return the expiry duration in nanoseconds, or {@link Long#MAX_VALUE} for no expiry
           */
          @Override
          public long expireAfterCreate(@NonNull Object key, @NonNull Object value, long currentTimeNanos) {
            if (value instanceof CacheEntry entry) {
              if (entry.getHardExpireAtMs() == Long.MAX_VALUE) {
                // Pure logical expiry: Caffeine never time-evicts this entry.
                // See Expiry Javadoc: Long.MAX_VALUE signals "no expiration".
                return Long.MAX_VALUE;
              }
              long remainingMs = entry.getHardExpireAtMs() - currentTimeMillis();
              return TimeUnit.MILLISECONDS.toNanos(Math.max(1, remainingMs));
            }
            return TimeUnit.MINUTES.toNanos(properties.getLocalCacheTtlMinutes());
          }

          /**
           * Re-compute the expiry duration after an entry is updated.
           * Preserves pure logical expiry across updates; otherwise
           * recalculates from the entry's {@code hardExpireAtMs}.
           *
           * @param key              the cache key
           * @param value            the cache value (expected to be a {@link CacheEntry})
           * @param currentTimeNanos the current time in nanoseconds (provided by Caffeine)
           * @param currentDuration  the current expiry duration in nanoseconds
           * @return the updated expiry duration in nanoseconds, or {@link Long#MAX_VALUE} for no expiry
           */
          @Override
          public long expireAfterUpdate(
            @NonNull Object key,
            @NonNull Object value,
            long currentTimeNanos,
            long currentDuration
          ) {
            if (value instanceof CacheEntry entry) {
              if (entry.getHardExpireAtMs() == Long.MAX_VALUE) {
                // Preserve pure logical expiry across updates (e.g. broadcast refresh).
                return Long.MAX_VALUE;
              }
              long remainingMs = entry.getHardExpireAtMs() - currentTimeMillis();
              return TimeUnit.MILLISECONDS.toNanos(Math.max(1, remainingMs));
            }
            return currentDuration;
          }

          /**
           * Preserve the current expiry duration on read — reads never
           * extend or shorten the entry's time-to-live.
           *
           * @param key              the cache key
           * @param value            the cache value
           * @param currentTimeNanos the current time in nanoseconds (provided by Caffeine)
           * @param currentDuration  the current expiry duration in nanoseconds
           * @return the unchanged expiry duration in nanoseconds
           */
          @Override
          public long expireAfterRead(
            @NonNull Object key,
            @NonNull Object value,
            long currentTimeNanos,
            long currentDuration
          ) {
            return currentDuration;
          }
        }
      );
    return builder.build();
  }
}

1	/*
2	* Copyright 2026 Hyshmily. All Rights Reserved.
3	*
4	* Licensed under the Apache License, Version 2.0 (the "License");
5	* you may not use this file except in compliance with the License.
6	* You may obtain a copy of the License at
7	*
8	* http://www.apache.org/licenses/LICENSE-2.0
9	*
10	* Unless required by applicable law or agreed to in writing, software
11	* distributed under the License is distributed on an "AS IS" BASIS,
12	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13	* See the License for the specific language governing permissions and
14	* limitations under the License.
15	*/
16	package io.github.hyshmily.hotkey.autoconfigure;
17
18	import static io.github.hyshmily.hotkey.util.TimeSource.currentTimeMillis;
19
20	import com.github.benmanes.caffeine.cache.Cache;
21	import com.github.benmanes.caffeine.cache.Caffeine;
22	import com.github.benmanes.caffeine.cache.Expiry;
23	import io.github.hyshmily.hotkey.HotKey;
24	import io.github.hyshmily.hotkey.Internal;
25	import io.github.hyshmily.hotkey.cache.HotKeyCache;
26	import io.github.hyshmily.hotkey.cache.cachesupport.CacheExpireManager;
27	import io.github.hyshmily.hotkey.cache.cachesupport.HotKeyCircuitBreaker;
28	import io.github.hyshmily.hotkey.cache.cachesupport.SingleFlight;
29	import io.github.hyshmily.hotkey.constants.HotKeyConstants;
30	import io.github.hyshmily.hotkey.hotkeydetector.HotKeyDetector;
31	import io.github.hyshmily.hotkey.hotkeydetector.heavykeeper.HeavyKeeper;
32	import io.github.hyshmily.hotkey.hotkeydetector.heavykeeper.TopK;
33	import io.github.hyshmily.hotkey.model.CacheEntry;
34	import io.github.hyshmily.hotkey.reporting.HotKeyReporter;
35	import io.github.hyshmily.hotkey.rule.RuleMatcher;
36	import io.github.hyshmily.hotkey.sharding.ClusterHealthView;
37	import io.github.hyshmily.hotkey.sync.local.CacheSyncPublisher;
38	import io.github.hyshmily.hotkey.util.version.VersionController;
39	import java.util.Optional;
40	import java.util.concurrent.Executor;
41	import java.util.concurrent.RejectedExecutionException;
42	import java.util.concurrent.ScheduledExecutorService;
43	import java.util.concurrent.TimeUnit;
44	import lombok.extern.slf4j.Slf4j;
45	import org.jspecify.annotations.NonNull;
46	import org.springframework.beans.factory.ObjectProvider;
47	import org.springframework.beans.factory.annotation.Qualifier;
48	import org.springframework.boot.autoconfigure.AutoConfiguration;
49	import org.springframework.boot.autoconfigure.condition.ConditionalOnBean;
50	import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
51	import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
52	import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
53	import org.springframework.boot.context.properties.EnableConfigurationProperties;
54	import org.springframework.context.annotation.Bean;
55	import org.springframework.data.redis.core.StringRedisTemplate;
56	import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;
57
58	/**
59	* App-side autoconfiguration for the HotKey library.
60	*
61	* <p>Creates the app-side {@link TopK} detector (HeavyKeeper), L1 Caffeine
62	* cache, {@link SingleFlight} deduplication layer, executor, and the
63	* primary {@link HotKeyCache} (without Redis version tracking when Redis
64	* is absent).
65	*
66	* <p><b>Condition:</b> this configuration is <em>skipped</em> when the
67	* Worker is active ({@code hotkey.worker.enabled=true}). It runs when
68	* Worker is disabled or the property is absent.
69	*/
70	@Internal
71	@AutoConfiguration(after = RedisAutoConfiguration.class)
72	@ConditionalOnProperty(prefix = "hotkey.worker", name = "enabled", havingValue = "false", matchIfMissing = true)
73	@EnableConfigurationProperties(HotKeyProperties.class)
74	@Slf4j	4✔
75	public class HotKeyAutoConfiguration {	3✔
76
77	/**
78	* Create the app-side TopK instance (HeavyKeeper) as a standalone bean.
79	*
80	* <p>The HeavyKeeper uses a Count-Min Sketch augmented with a minimum-count
81	* threshold and exponential decay to track the top-K hottest keys with high
82	* accuracy and low memory footprint. Configuration parameters (width, depth,
83	* decay, minCount, topK capacity, expelled queue capacity) are read from
84	* {@link HotKeyProperties}.
85	*
86	* @param properties the HotKey configuration properties (never {@code null})
87	* @return a new HeavyKeeper TopK instance
88	*/
89	@Bean
90	@ConditionalOnMissingBean
91	public HeavyKeeper heavyKeeper(HotKeyProperties properties) {
92	return new HeavyKeeper(	4✔
93	properties.getTopK(),	2✔
94	properties.getWidth(),	2✔
95	properties.getDepth(),	2✔
96	properties.getDecay(),	2✔
97	properties.getMinCount(),	2✔
98	properties.getExpelledQueueCapacity(),	2✔
99	properties.getSketchWindowCount()	2✔
100	);
101	}
102
103	/**
104	* Create the app-side {@link HotKeyDetector} facade that wraps the HeavyKeeper TopK
105	* and schedules periodic decay.
106	*
107	* <p>The detector provides the primary hot-key detection API ({@code add()}, {@code list()},
108	* {@code total()}) and schedules the periodic HeavyKeeper decay using the shared scheduler.
109	* This bean is the {@code @Qualifier("hotKeyDetector")} target for injection into
110	* {@link HotKeyCache} and other components.
111	*
112	* @param heavyKeeper the HeavyKeeper TopK instance (never {@code null})
113	* @param hotKeyScheduler the shared scheduler for periodic tasks (never {@code null})
114	* @return a new HotKeyDetector instance
115	*/
116	@Bean
117	@ConditionalOnMissingBean
118	@SuppressWarnings("SpringJavaInjectionPointsAutowiringInspection")
119	public HotKeyDetector hotKeyDetector(
120	HeavyKeeper heavyKeeper,
121	@Qualifier("hotKeyScheduler") ScheduledExecutorService hotKeyScheduler
122	) {
123	return new HotKeyDetector(heavyKeeper, hotKeyScheduler);	6✔
124	}
125
126	/**
127	* Create the SingleFlight deduplication layer for concurrent cache-load requests.
128	*
129	* <p>When multiple threads request the same key simultaneously (a cache miss), the
130	* first caller triggers the load and subsequent callers wait for the same result
131	* rather than duplicating the load. Configuration parameters (max in-flight entries,
132	* TTL, timeout) are read from {@link HotKeyProperties}.
133	*
134	* @param properties the HotKey configuration properties (never {@code null})
135	* @param hotKeyExecutor the dedicated HotKey executor for async load execution (never {@code null})
136	* @return a new SingleFlight instance
137	*/
138	@Bean
139	@ConditionalOnMissingBean
140	public SingleFlight singleFlight(HotKeyProperties properties, @Qualifier("hotKeyExecutor") Executor hotKeyExecutor) {
141	return new SingleFlight(	4✔
142	properties.getInflightMaxSize(),	2✔
143	properties.getInflightTtlSeconds(),	2✔
144	properties.getInflightTimeoutSeconds(),	5✔
145	hotKeyExecutor,
146	new HotKeyCircuitBreaker(properties.getCircuitBreaker())	3✔
147	);
148	}
149
150	/**
151	* Create the soft/hard expiration manager that manages time-based eviction.
152	*
153	* <p>The soft-expire mechanism triggers an asynchronous refresh when a configurable
154	* portion of the TTL has elapsed, serving stale data while fetching a fresh value
155	* in the background. The hard-expire is the absolute maximum TTL enforced at the
156	* Caffeine level. The refresh pool size limits concurrent background refresh tasks
157	* to prevent resource exhaustion under high cache-miss rates.
158	*
159	* @param hotLocalCache the L1 Caffeine cache (never {@code null})
160	* @param hotKeyExecutor the dedicated HotKey executor for async refresh tasks (never {@code null})
161	* @param properties the HotKey configuration properties (never {@code null})
162	* @return a new CacheExpireManager instance
163	*/
164	@Bean
165	@ConditionalOnMissingBean
166	public CacheExpireManager expireManager(
167	Cache<String, Object> hotLocalCache,
168	@Qualifier("hotKeyExecutor") Executor hotKeyExecutor,
169	HotKeyProperties properties
170	) {
171	return new CacheExpireManager(hotLocalCache, hotKeyExecutor, properties, properties.getRefreshMaxPools());	9✔
172	}
173
174	/**
175	* Create the dedicated thread-pool executor for asynchronous cache operations.
176	*
177	* <p>This executor handles all async operations in the HotKey data path: cache loading
178	* via SingleFlight, soft-expiry refresh tasks, and cross-instance broadcast callbacks.
179	* Uses a bounded thread pool to limit concurrent AMQP channel usage (RabbitMQ's
180	* {@code CachingConnectionFactory} associates channels with platform threads, so
181	* unbounded virtual-thread concurrency causes channel-open timeouts). The pool is
182	* configured with core/max pool size, bounded queue capacity, and a rejection policy
183	* that throws {@link RejectedExecutionException} when the queue is full. On shutdown,
184	* in-progress tasks are allowed to complete with a 60-second grace period.
185	*
186	* @param properties the HotKey configuration properties (never {@code null})
187	* @return a configured {@link ThreadPoolTaskExecutor}
188	*/
189	@Bean("hotKeyExecutor")
190	@ConditionalOnMissingBean(name = "hotKeyExecutor")
191	public Executor hotKeyExecutor(HotKeyProperties properties) {
192	ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();	4✔
193	executor.setCorePoolSize(properties.getExecutorCorePoolSize());	4✔
194	executor.setMaxPoolSize(properties.getExecutorMaxPoolSize());	4✔
195	executor.setQueueCapacity(properties.getExecutorQueueCapacity());	4✔
196	executor.setThreadNamePrefix(HotKeyConstants.THREAD_PREFIX_HOTKEY);	3✔
197	executor.setWaitForTasksToCompleteOnShutdown(true);	3✔
198	executor.setAwaitTerminationSeconds(60);	3✔
199	executor.setRejectedExecutionHandler((r, exe) -> {	4✔
200	log.warn(	×
201	"HotKey executor task rejected: corePool={}, maxPool={}, queueCapacity={}",
202	properties.getExecutorCorePoolSize(),	×
203	properties.getExecutorMaxPoolSize(),	×
204	properties.getExecutorQueueCapacity()	×
205	);
206	throw new RejectedExecutionException("HotKey executor queue full");	×
207	});
208	executor.initialize();	2✔
209	return executor;	2✔
210	}
211
212	/**
213	* Create the {@link RuleMatcher} for key matching against user-defined rules.
214	*
215	* <p>This variant is wired with an empty Redis provider and an optional sync
216	* publisher, since no {@link StringRedisTemplate} is available in the non-Redis
217	* deployment mode. Rules are kept in-memory only and do not survive restarts.
218	* When Redis is available, {@link HotKeyRedisAutoConfiguration#ruleMatcher}
219	* takes over with Redis persistence.
220	*
221	* @param publisherProvider optional provider for the cache sync publisher (may be absent)
222	* @return a new RuleMatcher instance (in-memory only)
223	*/
224	@Bean
225	@ConditionalOnMissingBean({ RuleMatcher.class, StringRedisTemplate.class })
226	public RuleMatcher ruleMatcher(ObjectProvider<CacheSyncPublisher> publisherProvider) {
227	return new RuleMatcher(Optional.empty(), Optional.ofNullable(publisherProvider.getIfAvailable()));	9✔
228	}
229
230	/**
231	* Create the {@link HotKeyCache} (non-Redis variant).
232	*
233	* <p>Only active when {@code RedisTemplate} is absent; otherwise
234	* {@link HotKeyRedisAutoConfiguration#hotKeyCache} takes over. Creates a
235	* {@link VersionController} with an empty Redis provider (falling back to
236	* node-local counters) and default ring manager / health view when none are
237	* available from the application context.
238	*
239	* @param hotKeyDetector the app-side TopK detector (never {@code null})
240	* @param hotLocalCache the L1 Caffeine cache (never {@code null})
241	* @param singleFlight the deduplication layer (never {@code null})
242	* @param expireManager the soft/hard expiration manager (never {@code null})
243	* @param syncPublisher optional cache sync publisher (may be absent)
244	* @param hotKeyReporter optional hot key reporter (may be absent; e.g. in Worker-only mode)
245	* @param hotKeyExecutor the dedicated HotKey executor (never {@code null})
246	* @param properties the HotKey configuration properties (never {@code null})
247	* @param ruleMatcher the rule matcher instance (never {@code null})
248	* @param healthViewProvider provider for the cluster health view (creates default if absent)
249	* @return a new HotKeyCache instance with node-local version tracking
250	*/
251	@Bean
252	@ConditionalOnMissingBean(type = "org.springframework.data.redis.core.RedisTemplate")
253	public HotKeyCache hotKeyCache(
254	@Qualifier("hotKeyDetector") HotKeyDetector hotKeyDetector,
255	Cache<String, Object> hotLocalCache,
256	SingleFlight singleFlight,
257	CacheExpireManager expireManager,
258	Optional<CacheSyncPublisher> syncPublisher,
259	Optional<HotKeyReporter> hotKeyReporter,
260	@Qualifier("hotKeyExecutor") Executor hotKeyExecutor,
261	HotKeyProperties properties,
262	RuleMatcher ruleMatcher,
263	ObjectProvider<ClusterHealthView> healthViewProvider
264	) {
265	return new HotKeyCache(	13✔
266	hotKeyDetector,
267	hotLocalCache,
268	singleFlight,
269	expireManager,
270	hotKeyExecutor,
271	syncPublisher,
272	hotKeyReporter,
273	ruleMatcher,
274	new VersionController(Optional.empty(), properties.getVersionKeyTtlMinutes()),	8✔
275	properties,
276	new ClusterHealthView(
277	properties.getExpectedWorkerCount(),	2✔
278	properties.getHeartbeat().getTimeoutMs(),	4✔
279	properties.getHeartbeat().getDegradeAfterFailures()	4✔
280	)
281	);
282	}
283
284	/**
285	* Fallback {@link HotKey} facade bean.
286	*
287	* <p>Only active when a {@link HotKeyCache} bean exists but no {@link HotKey}
288	* has been defined yet. The primary {@link HotKey} creator is
289	* {@link HotKeyFacadeAutoConfiguration} — this fallback covers the case where
290	* that auto-configuration is excluded or its bean is overridden.
291	*
292	* @param hotKeyCache the HotKeyCache instance (never {@code null})
293	* @param appHotKeyDetector the app-side TopK detector (never {@code null})
294	* @param workerTopKProvider the Worker-side TopK algorithm (may be {@code null})
295	* @return a new HotKey facade instance
296	*/
297	@Bean
298	@ConditionalOnBean(HotKeyCache.class)
299	@ConditionalOnMissingBean
300	public HotKey hotKey(
301	HotKeyCache hotKeyCache,
302	@Qualifier("hotKeyDetector") HotKeyDetector appHotKeyDetector,
303	@Qualifier("workerTopK") ObjectProvider<TopK> workerTopKProvider
304	) {
305	return new HotKey(hotKeyCache, appHotKeyDetector, workerTopKProvider.getIfAvailable());	9✔
306	}
307
308	/**
309	* Create the L1 Caffeine cache instance.
310	*
311	* <p>Time-based expiry operates at the <em>Caffeine</em> level via a custom
312	* {@link Expiry} implementation, computing remaining nanoseconds from
313	* . Entries with
314	* {@code hardExpireAtMs == Long.MAX_VALUE} are purely logical-expiry
315	* — Caffeine never evicts them by time; they live until size eviction or
316	* manual invalidation. Reads never extend the expiry duration (no read-based
317	* refresh), ensuring predictable TTL behavior.
318	*
319	* <p>The maximum cache size is configured via {@code hotkey.local.local-cache-max-size}
320	* (default 1000 entries). Time-based TTL for entries without an explicit hard-expire
321	* timestamp defaults to {@code hotkey.local.local-cache-ttl-minutes} (default 5 minutes).
322	*
323	* @param properties the HotKey configuration properties (never {@code null})
324	* @return a configured Caffeine {@link Cache} instance
325	*/
326	@Bean
327	@ConditionalOnMissingBean
328	public Cache<String, Object> hotLocalCache(HotKeyProperties properties) {
329	Caffeine<Object, Object> builder = Caffeine.newBuilder()	2✔
330	.maximumSize(properties.getLocalCacheMaxSize())	8✔
331	.expireAfter(	2✔
332	new Expiry<>() {	9✔
333	/**
334	* Compute the time-to-live for a newly created cache entry.
335	* Returns {@link Long#MAX_VALUE} for pure logical-expiry entries
336	* (where {@code hardExpireAtMs == Long.MAX_VALUE}); otherwise
337	* computes the remaining wall-clock time.
338	*
339	* @param key the cache key
340	* @param value the cache value (expected to be a {@link CacheEntry})
341	* @param currentTimeNanos the current time in nanoseconds (provided by Caffeine)
342	* @return the expiry duration in nanoseconds, or {@link Long#MAX_VALUE} for no expiry
343	*/
344	@Override
345	public long expireAfterCreate(@NonNull Object key, @NonNull Object value, long currentTimeNanos) {
346	if (value instanceof CacheEntry entry) {	3!
347	if (entry.getHardExpireAtMs() == Long.MAX_VALUE) {	×
348	// Pure logical expiry: Caffeine never time-evicts this entry.
349	// See Expiry Javadoc: Long.MAX_VALUE signals "no expiration".
350	return Long.MAX_VALUE;	×
351	}
352	long remainingMs = entry.getHardExpireAtMs() - currentTimeMillis();	×
353	return TimeUnit.MILLISECONDS.toNanos(Math.max(1, remainingMs));	×
354	}
355	return TimeUnit.MINUTES.toNanos(properties.getLocalCacheTtlMinutes());	7✔
356	}
357
358	/**
359	* Re-compute the expiry duration after an entry is updated.
360	* Preserves pure logical expiry across updates; otherwise
361	* recalculates from the entry's {@code hardExpireAtMs}.
362	*
363	* @param key the cache key
364	* @param value the cache value (expected to be a {@link CacheEntry})
365	* @param currentTimeNanos the current time in nanoseconds (provided by Caffeine)
366	* @param currentDuration the current expiry duration in nanoseconds
367	* @return the updated expiry duration in nanoseconds, or {@link Long#MAX_VALUE} for no expiry
368	*/
369	@Override
370	public long expireAfterUpdate(
371	@NonNull Object key,
372	@NonNull Object value,
373	long currentTimeNanos,
374	long currentDuration
375	) {
376	if (value instanceof CacheEntry entry) {	×
377	if (entry.getHardExpireAtMs() == Long.MAX_VALUE) {	×
378	// Preserve pure logical expiry across updates (e.g. broadcast refresh).
379	return Long.MAX_VALUE;	×
380	}
381	long remainingMs = entry.getHardExpireAtMs() - currentTimeMillis();	×
382	return TimeUnit.MILLISECONDS.toNanos(Math.max(1, remainingMs));	×
383	}
384	return currentDuration;	×
385	}
386
387	/**
388	* Preserve the current expiry duration on read — reads never
389	* extend or shorten the entry's time-to-live.
390	*
391	* @param key the cache key
392	* @param value the cache value
393	* @param currentTimeNanos the current time in nanoseconds (provided by Caffeine)
394	* @param currentDuration the current expiry duration in nanoseconds
395	* @return the unchanged expiry duration in nanoseconds
396	*/
397	@Override
398	public long expireAfterRead(
399	@NonNull Object key,
400	@NonNull Object value,
401	long currentTimeNanos,
402	long currentDuration
403	) {
404	return currentDuration;	×
405	}
406	}
407	);
408	return builder.build();	3✔
409	}
410	}

Hyshmily / hotkey / 28637103998

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