Polish micrometer-registry-health module

implementations/micrometer-registry-health/src/main/java/io/micrometer/health/HealthConfig.java

@@ -21,6 +21,12 @@
 
 import static io.micrometer.core.instrument.config.validate.PropertyValidator.getDuration;
 
+/**
+ * {@link MeterRegistryConfig} for {@link HealthMeterRegistry}.
+ *
+ * @author Jon Schneider
+ * @since 1.6.0
+ */
 public interface HealthConfig extends MeterRegistryConfig {
     HealthConfig DEFAULT = key -> null;
 

implementations/micrometer-registry-health/src/main/java/io/micrometer/health/QueryUtils.java

@@ -17,24 +17,23 @@
 
 import java.util.function.BinaryOperator;
 
+/**
+ * Utilities for queries.
+ *
+ * @author Jon Schneider
+ */
 class QueryUtils {
-    public static final BinaryOperator<Double> SUM_OR_NAN = (v1, v2) -> {
+    static final BinaryOperator<Double> SUM_OR_NAN = (v1, v2) -> {
         if (Double.isNaN(v1)) {
-            if (Double.isNaN(v2)) {
-                return Double.NaN;
-            }
             return v2;
         } else if (Double.isNaN(v2)) {
             return v1;
         }
         return v1 + v2;
     };
 
-    public static final BinaryOperator<Double> MAX_OR_NAN = (v1, v2) -> {
+    static final BinaryOperator<Double> MAX_OR_NAN = (v1, v2) -> {
         if (Double.isNaN(v1)) {
-            if (Double.isNaN(v2)) {
-                return Double.NaN;
-            }
             return v2;
         } else if (Double.isNaN(v2)) {
             return v1;

implementations/micrometer-registry-health/src/main/java/io/micrometer/health/ServiceLevelObjective.java

@@ -20,6 +20,7 @@
 import io.micrometer.core.instrument.binder.MeterBinder;
 import io.micrometer.core.instrument.composite.CompositeMeterRegistry;
 import io.micrometer.core.instrument.config.MeterFilter;
+import io.micrometer.core.instrument.distribution.HistogramSupport;
 import io.micrometer.core.instrument.distribution.ValueAtPercentile;
 import io.micrometer.core.instrument.search.Search;
 import io.micrometer.core.lang.Nullable;
@@ -64,11 +65,14 @@ public abstract class ServiceLevelObjective {
     @Nullable
     private final String failedMessage;
 
+    private final Meter.Id id;
+
     protected ServiceLevelObjective(String name, Tags tags, @Nullable String baseUnit, @Nullable String failedMessage) {
         this.name = name;
         this.tags = tags;
         this.baseUnit = baseUnit;
         this.failedMessage = failedMessage;
+        this.id = new Meter.Id(name, tags, baseUnit, failedMessage, Meter.Type.GAUGE);
     }
 
     public String getName() {
@@ -85,7 +89,7 @@ public String getBaseUnit() {
     }
 
     public Meter.Id getId() {
-        return new Meter.Id(name, tags, baseUnit, failedMessage, Meter.Type.GAUGE);
+        return id;
     }
 
     @Nullable
@@ -125,7 +129,7 @@ protected SingleIndicator(NumericQuery query, String testDescription, Predicate<
 
         @Override
         public boolean healthy(MeterRegistry registry) {
-            Double v = query.getValue(registry);
+            Double v = getValue(registry);
             return v.isNaN() || test.test(v);
         }
 
@@ -181,8 +185,7 @@ public static class Builder {
             private final Collection<MeterBinder> requires;
 
             Builder(String name) {
-                this.name = name;
-                this.requires = new ArrayList<>();
+                this(name, null, new ArrayList<>());
             }
 
             Builder(String name, @Nullable String failedMessage, Collection<MeterBinder> requires) {
@@ -215,7 +218,7 @@ public final Builder tags(String... tags) {
             }
 
             /**
-             * @param tags Tags to add to the eventual timer.
+             * @param tags Tags to add to the single indicator.
              * @return The builder with added tags.
              */
             public final Builder tags(Iterable<Tag> tags) {
@@ -226,7 +229,7 @@ public final Builder tags(Iterable<Tag> tags) {
             /**
              * @param key   The tag key.
              * @param value The tag value.
-             * @return The timer builder with a single added tag.
+             * @return The single indicator builder with a single added tag.
              */
             public final Builder tag(String key, String value) {
                 this.tags = tags.and(key, value);
@@ -278,15 +281,11 @@ public final NumericQuery total(Function<Search, Search> search) {
             public final NumericQuery maxPercentile(Function<Search, Search> search, double percentile) {
                 return new Instant(name, tags, baseUnit, failedMessage, requires, search, s -> s.meters().stream()
                         .map(m -> {
-                            ValueAtPercentile[] valueAtPercentiles = new ValueAtPercentile[0];
-                            if (m instanceof DistributionSummary) {
-                                valueAtPercentiles = ((DistributionSummary) m).takeSnapshot().percentileValues();
-                            } else if (m instanceof Timer) {
-                                valueAtPercentiles = ((Timer) m).takeSnapshot().percentileValues();
-                            } else if (m instanceof LongTaskTimer) {
-                                valueAtPercentiles = ((LongTaskTimer) m).takeSnapshot().percentileValues();
+                            if (!(m instanceof HistogramSupport)) {
+                                return Double.NaN;
                             }
 
+                            ValueAtPercentile[] valueAtPercentiles = ((HistogramSupport) m).takeSnapshot().percentileValues();
                             return Arrays.stream(valueAtPercentiles)
                                     .filter(vap -> vap.percentile() == percentile)
                                     .map(ValueAtPercentile::value)
@@ -653,7 +652,7 @@ public Builder tags(String... tags) {
             }
 
             /**
-             * @param tags Tags to add to the eventual timer.
+             * @param tags Tags to add to the multiple indicator.
              * @return The builder with added tags.
              */
             public Builder tags(Iterable<Tag> tags) {

implementations/micrometer-registry-health/src/main/java/io/micrometer/health/objectives/JvmServiceLevelObjectives.java

@@ -23,6 +23,8 @@
 import java.time.Duration;
 
 /**
+ * {@link ServiceLevelObjective ServiceLevelObjectives} for Java Virtual Machine.
+ *
  * @author Jon Schneider
  * @since 1.6.0
  */
@@ -31,7 +33,7 @@ public class JvmServiceLevelObjectives {
      * A series of high-level heap monitors originally defined in
      * <a href="https://www.jetbrains.com/help/teamcity/teamcity-memory-monitor.html">Team City's memory monitor</a>.
      */
-    public static final ServiceLevelObjective[] MEMORY = new ServiceLevelObjective[]{
+    public static final ServiceLevelObjective[] MEMORY = new ServiceLevelObjective[] {
             ServiceLevelObjective
                     .build("jvm.pool.memory")
                     .failedMessage("Memory usage in a single memory pool exceeds 90% after garbage collection.")
@@ -44,6 +46,7 @@ public class JvmServiceLevelObjectives {
                     .build("jvm.gc.load")
                     .failedMessage("Memory cleaning is taking more than 50% of CPU resources on average. " +
                             "This usually means really serious problems with memory resulting in high performance degradation.")
+                    .requires(new JvmHeapPressureMetrics())
                     .baseUnit("percent CPU time spent")
                     .value(s -> s.name("jvm.gc.overhead"))
                     .isLessThan(0.5),
@@ -72,7 +75,7 @@ public class JvmServiceLevelObjectives {
                     .and()
     };
 
-    public static final ServiceLevelObjective[] ALLOCATIONS = new ServiceLevelObjective[]{
+    public static final ServiceLevelObjective[] ALLOCATIONS = new ServiceLevelObjective[] {
             ServiceLevelObjective
                     .build("jvm.allocations.g1.humongous")
                     .failedMessage("A single object was allocated that exceeded 50% of the total size of the eden space.")

implementations/micrometer-registry-health/src/main/java/io/micrometer/health/objectives/OperatingSystemServiceLevelObjectives.java

@@ -19,11 +19,13 @@
 import io.micrometer.health.ServiceLevelObjective;
 
 /**
+ * {@link ServiceLevelObjective ServiceLevelObjectives} for Operating System.
+ *
  * @author Jon Schneider
  * @since 1.6.0
  */
 public class OperatingSystemServiceLevelObjectives {
-    public static final ServiceLevelObjective[] DISK = new ServiceLevelObjective[]{
+    public static final ServiceLevelObjective[] DISK = new ServiceLevelObjective[] {
             ServiceLevelObjective.build("os.file.descriptors")
                     .failedMessage("Too many file descriptors are open. When the max is reached, " +
                             "further attempts to retrieve a file descriptor will block indefinitely.")

implementations/micrometer-registry-health/src/main/java/io/micrometer/health/package-info.java

@@ -13,6 +13,10 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
+
+/**
+ * SLO-based health meter registry.
+ */
 @NonNullApi
 @NonNullFields
 package io.micrometer.health;

implementations/micrometer-registry-health/src/test/java/io/micrometer/health/HealthMeterRegistryTest.java

@@ -29,6 +29,11 @@
 import static io.micrometer.core.instrument.MockClock.clock;
 import static org.assertj.core.api.Assertions.assertThat;
 
+/**
+ * Tests for {@link HealthMeterRegistry}.
+ *
+ * @author Jon Schneider
+ */
 class HealthMeterRegistryTest {
     @Test
     void healthFromServiceLevelObjective() {
@@ -123,8 +128,7 @@ void applyRequiredBinders() {
                 .build();
 
         assertThat(registry.getMeters().stream().map(m -> m.getId().getName()))
-                .containsOnly("jvm.memory.used")
-                .isNotEmpty();
+                .containsOnly("jvm.memory.used");
     }
 
     @Test
@@ -143,7 +147,6 @@ public Meter.Id map(Meter.Id id) {
 
         assertThat(registry.getServiceLevelObjectives().stream().map(ServiceLevelObjective::getName))
                 .contains("jvm.collection.load")
-                .doesNotContain("jvm.pool.memory")
-                .isNotEmpty();
+                .doesNotContain("jvm.pool.memory");
     }
 }

implementations/micrometer-registry-health/src/test/java/io/micrometer/health/QueryTest.java

@@ -156,15 +156,15 @@ void isLessThan() {
                         .count(s -> s.name("my.timer"))
                         .isLessThan(4)
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
 
         assertThat(
                 ServiceLevelObjective
                         .build("sum")
                         .total(s -> s.name("my.timer"))
                         .isLessThan(Duration.ofSeconds(6))
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
     }
 
     @Test
@@ -175,14 +175,14 @@ void isLessThanOrEqualTo() {
                         .count(s -> s.name("my.timer"))
                         .isLessThanOrEqualTo(3)
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
 
         assertThat(ServiceLevelObjective
                 .build("sum")
                 .total(s -> s.name("my.timer"))
                 .isLessThanOrEqualTo(Duration.ofSeconds(5))
                 .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
     }
 
     @Test
@@ -193,15 +193,15 @@ void isGreaterThan() {
                         .count(s -> s.name("my.timer"))
                         .isGreaterThan(2)
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
 
         assertThat(
                 ServiceLevelObjective
                         .build("sum")
                         .total(s -> s.name("my.timer"))
                         .isGreaterThan(Duration.ofSeconds(4))
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
     }
 
     @Test
@@ -212,15 +212,15 @@ void isGreaterThanOrEqualTo() {
                         .count(s -> s.name("my.timer"))
                         .isGreaterThanOrEqualTo(3)
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
 
         assertThat(
                 ServiceLevelObjective
                         .build("sum")
                         .total(s -> s.name("my.timer"))
                         .isGreaterThanOrEqualTo(Duration.ofSeconds(5))
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
     }
 
     @Test
@@ -231,14 +231,14 @@ void isEqualTo() {
                         .count(s -> s.name("my.timer"))
                         .isEqualTo(3)
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
 
         assertThat(
                 ServiceLevelObjective
                         .build("sum")
                         .total(s -> s.name("my.timer"))
                         .isEqualTo(Duration.ofSeconds(5))
                         .healthy(registry)
-        ).isEqualTo(true);
+        ).isTrue();
     }
 }