Expose cache metrics for Redis

This commit adds support for Redis cache metrics. Users can opt-in for
statistics using the "spring.cache.redis.enable-statistics" property.

Closes gh-22701

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/cache/RedisCacheMeterBinderProviderTests.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.boot.actuate.metrics.cache;
+
+import java.util.Collections;
+
+import io.micrometer.core.instrument.binder.MeterBinder;
+import org.junit.jupiter.api.Test;
+
+import org.springframework.data.redis.cache.RedisCache;
+
+import static org.assertj.core.api.Assertions.assertThat;
+import static org.mockito.BDDMockito.given;
+import static org.mockito.Mockito.mock;
+
+/**
+ * Tests for {@link RedisCacheMeterBinderProvider}.
+ *
+ * @author Stephane Nicoll
+ */
+class RedisCacheMeterBinderProviderTests {
+
+	@Test
+	void redisCacheProvider() {
+		RedisCache cache = mock(RedisCache.class);
+		given(cache.getName()).willReturn("test");
+		MeterBinder meterBinder = new RedisCacheMeterBinderProvider().getMeterBinder(cache, Collections.emptyList());
+		assertThat(meterBinder).isInstanceOf(RedisCacheMetrics.class);
+	}
+
+}

spring-boot-project/spring-boot-actuator/src/test/java/org/springframework/boot/actuate/metrics/cache/RedisCacheMetricsTests.java

@@ -0,0 +1,139 @@
+/*
+ * Copyright 2012-2020 the original author or authors.
+ *
+ * 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
+ *
+ *      https://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 org.springframework.boot.actuate.metrics.cache;
+
+import java.util.UUID;
+import java.util.function.BiConsumer;
+
+import io.micrometer.core.instrument.MeterRegistry;
+import io.micrometer.core.instrument.Tags;
+import io.micrometer.core.instrument.simple.SimpleMeterRegistry;
+import org.junit.jupiter.api.Test;
+import org.testcontainers.junit.jupiter.Container;
+import org.testcontainers.junit.jupiter.Testcontainers;
+
+import org.springframework.boot.autoconfigure.AutoConfigurations;
+import org.springframework.boot.autoconfigure.cache.CacheAutoConfiguration;
+import org.springframework.boot.autoconfigure.data.redis.RedisAutoConfiguration;
+import org.springframework.boot.test.context.assertj.AssertableApplicationContext;
+import org.springframework.boot.test.context.runner.ApplicationContextRunner;
+import org.springframework.boot.test.context.runner.ContextConsumer;
+import org.springframework.boot.testsupport.testcontainers.RedisContainer;
+import org.springframework.cache.annotation.EnableCaching;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.data.redis.cache.RedisCache;
+import org.springframework.data.redis.cache.RedisCacheManager;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+/**
+ * Tests for {@link RedisCacheMetrics}.
+ *
+ * @author Stephane Nicoll
+ */
+@Testcontainers(disabledWithoutDocker = true)
+class RedisCacheMetricsTests {
+
+	@Container
+	static final RedisContainer redis = new RedisContainer();
+
+	private static final Tags TAGS = Tags.of("app", "test").and("cache", "test");
+
+	private final ApplicationContextRunner contextRunner = new ApplicationContextRunner()
+			.withConfiguration(AutoConfigurations.of(RedisAutoConfiguration.class, CacheAutoConfiguration.class))
+			.withUserConfiguration(CachingConfiguration.class).withPropertyValues(
+					"spring.redis.host=" + redis.getHost(), "spring.redis.port=" + redis.getFirstMappedPort(),
+					"spring.cache.type=redis", "spring.cache.redis.enable-statistics=true");
+
+	@Test
+	void cacheStatisticsAreExposed() {
+		this.contextRunner.run(withCacheMetrics((cache, meterRegistry) -> {
+			assertThat(meterRegistry.find("cache.size").tags(TAGS).functionCounter()).isNull();
+			assertThat(meterRegistry.find("cache.gets").tags(TAGS.and("result", "hit")).functionCounter()).isNotNull();
+			assertThat(meterRegistry.find("cache.gets").tags(TAGS.and("result", "miss")).functionCounter()).isNotNull();
+			assertThat(meterRegistry.find("cache.gets").tags(TAGS.and("result", "pending")).functionCounter())
+					.isNotNull();
+			assertThat(meterRegistry.find("cache.evictions").tags(TAGS).functionCounter()).isNull();
+			assertThat(meterRegistry.find("cache.puts").tags(TAGS).functionCounter()).isNotNull();
+			assertThat(meterRegistry.find("cache.removals").tags(TAGS).functionCounter()).isNotNull();
+			assertThat(meterRegistry.find("cache.lock.duration").tags(TAGS).timeGauge()).isNotNull();
+		}));
+	}
+
+	@Test
+	void cacheHitsAreExposed() {
+		this.contextRunner.run(withCacheMetrics((cache, meterRegistry) -> {
+			String key = UUID.randomUUID().toString();
+			cache.put(key, "test");
+
+			cache.get(key);
+			cache.get(key);
+			assertThat(meterRegistry.get("cache.gets").tags(TAGS.and("result", "hit")).functionCounter().count())
+					.isEqualTo(2.0d);
+		}));
+	}
+
+	@Test
+	void cacheMissesAreExposed() {
+		this.contextRunner.run(withCacheMetrics((cache, meterRegistry) -> {
+			String key = UUID.randomUUID().toString();
+			cache.get(key);
+			cache.get(key);
+			cache.get(key);
+			assertThat(meterRegistry.get("cache.gets").tags(TAGS.and("result", "miss")).functionCounter().count())
+					.isEqualTo(3.0d);
+		}));
+	}
+
+	@Test
+	void cacheMetricsMatchCacheStatistics() {
+		this.contextRunner.run((context) -> {
+			RedisCache cache = getTestCache(context);
+			RedisCacheMetrics cacheMetrics = new RedisCacheMetrics(cache, TAGS);
+			assertThat(cacheMetrics.hitCount()).isEqualTo(cache.getStatistics().getHits());
+			assertThat(cacheMetrics.missCount()).isEqualTo(cache.getStatistics().getMisses());
+			assertThat(cacheMetrics.putCount()).isEqualTo(cache.getStatistics().getPuts());
+			assertThat(cacheMetrics.size()).isNull();
+			assertThat(cacheMetrics.evictionCount()).isNull();
+		});
+	}
+
+	private ContextConsumer<AssertableApplicationContext> withCacheMetrics(
+			BiConsumer<RedisCache, MeterRegistry> stats) {
+		return (context) -> {
+			RedisCache cache = getTestCache(context);
+			SimpleMeterRegistry meterRegistry = new SimpleMeterRegistry();
+			new RedisCacheMetrics(cache, Tags.of("app", "test")).bindTo(meterRegistry);
+			stats.accept(cache, meterRegistry);
+		};
+	}
+
+	private RedisCache getTestCache(AssertableApplicationContext context) {
+		assertThat(context).hasSingleBean(RedisCacheManager.class);
+		RedisCacheManager cacheManager = context.getBean(RedisCacheManager.class);
+		RedisCache cache = (RedisCache) cacheManager.getCache("test");
+		assertThat(cache).isNotNull();
+		return cache;
+	}
+
+	@Configuration(proxyBeanMethods = false)
+	@EnableCaching
+	static class CachingConfiguration {
+
+	}
+
+}