Merge commit '5e84eeebbf61739314b76e61c7f10b9af7c51759' into dev

* commit '5e84eeebbf61739314b76e61c7f10b9af7c51759':
  Extract Micrometer metric name to public constant and document usage
  Remove hard-coded percentiles from MicrometerMetricsTracker

src/main/java/com/zaxxer/hikari/metrics/micrometer/MicrometerMetricsTracker.java

@@ -9,20 +9,45 @@ import io.micrometer.core.instrument.Timer;
 
 import java.util.concurrent.TimeUnit;
 
+/**
+ * {@link IMetricsTracker Metrics tracker} for Micrometer.
+ * HikariCP metrics can be configured in your application by applying a
+ * {@link io.micrometer.core.instrument.config.MeterFilter MeterFilter} to metrics starting with
+ * {@link #HIKARI_METRIC_NAME_PREFIX}. For example, to configure client-side calculated percentiles:
+ *
+ * <blockquote><pre>
+ *     new MeterFilter() {
+ *       &#064;Override
+ *       public DistributionStatisticConfig configure(Meter.Id id, DistributionStatisticConfig config) {
+ *         if (id.getName().startsWith(MicrometerMetricsTracker.HIKARI_METRIC_NAME_PREFIX)) {
+ *           return DistributionStatisticConfig.builder()
+ *               .percentiles(0.5, 0.95)
+ *               .build()
+ *               .merge(config);
+ *            }
+ *         return config;
+ *         }
+ *      };
+ * </pre></blockquote>
+ */
 public class MicrometerMetricsTracker implements IMetricsTracker
 {
+   /** Prefix used for all HikariCP metric names. */
+   public static final String HIKARI_METRIC_NAME_PREFIX = "hikaricp";
+
    private static final String METRIC_CATEGORY = "pool";
-   private static final String METRIC_NAME_WAIT = "hikaricp.connections.acquire";
-   private static final String METRIC_NAME_USAGE = "hikaricp.connections.usage";
-   private static final String METRIC_NAME_CONNECT = "hikaricp.connections.creation";
-
-   private static final String METRIC_NAME_TIMEOUT_RATE = "hikaricp.connections.timeout";
-   private static final String METRIC_NAME_TOTAL_CONNECTIONS = "hikaricp.connections";
-   private static final String METRIC_NAME_IDLE_CONNECTIONS = "hikaricp.connections.idle";
-   private static final String METRIC_NAME_ACTIVE_CONNECTIONS = "hikaricp.connections.active";
-   private static final String METRIC_NAME_PENDING_CONNECTIONS = "hikaricp.connections.pending";
-   private static final String METRIC_NAME_MAX_CONNECTIONS = "hikaricp.connections.max";
-   private static final String METRIC_NAME_MIN_CONNECTIONS = "hikaricp.connections.min";
+   private static final String METRIC_NAME_WAIT = HIKARI_METRIC_NAME_PREFIX + ".connections.acquire";
+   private static final String METRIC_NAME_USAGE = HIKARI_METRIC_NAME_PREFIX + ".connections.usage";
+   private static final String METRIC_NAME_CONNECT = HIKARI_METRIC_NAME_PREFIX + ".connections.creation";
+
+   private static final String METRIC_NAME_TIMEOUT_RATE = HIKARI_METRIC_NAME_PREFIX + ".connections.timeout";
+   private static final String METRIC_NAME_TOTAL_CONNECTIONS = HIKARI_METRIC_NAME_PREFIX + ".connections";
+   private static final String METRIC_NAME_IDLE_CONNECTIONS = HIKARI_METRIC_NAME_PREFIX + ".connections.idle";
+   private static final String METRIC_NAME_ACTIVE_CONNECTIONS = HIKARI_METRIC_NAME_PREFIX + ".connections.active";
+   private static final String METRIC_NAME_PENDING_CONNECTIONS = HIKARI_METRIC_NAME_PREFIX + ".connections.pending";
+   private static final String METRIC_NAME_MAX_CONNECTIONS = HIKARI_METRIC_NAME_PREFIX + ".connections.max";
+   private static final String METRIC_NAME_MIN_CONNECTIONS = HIKARI_METRIC_NAME_PREFIX + ".connections.min";
+
 
    private final Timer connectionObtainTimer;
    private final Counter connectionTimeoutCounter;
@@ -49,19 +74,16 @@ public class MicrometerMetricsTracker implements IMetricsTracker
 
       this.connectionObtainTimer = Timer.builder(METRIC_NAME_WAIT)
          .description("Connection acquire time")
-         .publishPercentiles(0.95)
          .tags(METRIC_CATEGORY, poolName)
          .register(meterRegistry);
 
       this.connectionCreation = Timer.builder(METRIC_NAME_CONNECT)
          .description("Connection creation time")
-         .publishPercentiles(0.95)
          .tags(METRIC_CATEGORY, poolName)
          .register(meterRegistry);
 
       this.connectionUsage = Timer.builder(METRIC_NAME_USAGE)
          .description("Connection usage time")
-         .publishPercentiles(0.95)
          .tags(METRIC_CATEGORY, poolName)
          .register(meterRegistry);