Polish "Auto-configure Mongo metrics"

See gh-23990

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/productionreadyfeatures/metrics/mongo/SampleCommandTagsProviderConfiguration.java

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2012-2021 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.docs.productionreadyfeatures.metrics.mongo;
+
+// tag::code[]
+import com.mongodb.event.CommandEvent;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.binder.mongodb.MongoMetricsCommandTagsProvider;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+public class SampleCommandTagsProviderConfiguration {
+
+	@Bean
+	MongoMetricsCommandTagsProvider customCommandTagsProvider() {
+		return new CustomCommandTagsProvider();
+	}
+
+}
+// end::code[]
+
+class CustomCommandTagsProvider implements MongoMetricsCommandTagsProvider {
+
+	@Override
+	public Iterable<Tag> commandTags(CommandEvent commandEvent) {
+		return java.util.Collections.emptyList();
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/productionreadyfeatures/metrics/mongo/SampleConnectionPoolTagsProviderConfiguration.java

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+/*
+ * Copyright 2012-2021 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.docs.productionreadyfeatures.metrics.mongo;
+
+// tag::code[]
+import com.mongodb.event.ConnectionPoolCreatedEvent;
+import io.micrometer.core.instrument.Tag;
+import io.micrometer.core.instrument.binder.mongodb.MongoMetricsConnectionPoolTagsProvider;
+
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+
+@Configuration(proxyBeanMethods = false)
+public class SampleConnectionPoolTagsProviderConfiguration {
+
+	@Bean
+	MongoMetricsConnectionPoolTagsProvider customConnectionPoolTagsProvider() {
+		return new CustomConnectionPoolTagsProvider();
+	}
+
+}
+// end::code[]
+
+class CustomConnectionPoolTagsProvider implements MongoMetricsConnectionPoolTagsProvider {
+
+	@Override
+	public Iterable<Tag> connectionPoolTags(ConnectionPoolCreatedEvent event) {
+		return java.util.Collections.emptyList();
+	}
+
+}

spring-boot-project/spring-boot-docs/src/main/java/org/springframework/boot/docs/productionreadyfeatures/metrics/mongo/package-info.java

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+/*
+ * Copyright 2012-2021 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.
+ */
+
+/**
+ * Examples for the "Production Ready Features - Metrics - MongoDB" section.
+ */
+package org.springframework.boot.docs.productionreadyfeatures.metrics.mongo;