Plugs-in the DoubleGauge into the registry (#1503)

5 files changed, 185 insertions, 8 deletions

diff --git a/api/src/main/java/io/opencensus/metrics/DoubleGauge.java b/api/src/main/java/io/opencensus/metrics/DoubleGauge.java
index de2b053b..32759973 100644
--- a/api/src/main/java/io/opencensus/metrics/DoubleGauge.java
+++ b/api/src/main/java/io/opencensus/metrics/DoubleGauge.java
@@ -32,7 +32,7 @@ import javax.annotation.concurrent.ThreadSafe;
  *   private static final MetricRegistry metricRegistry = Metrics.getMetricRegistry();
  *
  *   List<LabelKey> labelKeys = Arrays.asList(LabelKey.create("Name", "desc"));
- *   // TODO(mayurkale): Plugs-in the DoubleGauge into the registry.
+ *
  *   DoubleGauge gauge = metricRegistry.addDoubleGauge("queue_size",
  *                       "Pending jobs", "1", labelKeys);
  *
@@ -57,7 +57,6 @@ import javax.annotation.concurrent.ThreadSafe;
  *   List<LabelKey> labelKeys = Arrays.asList(LabelKey.create("Name", "desc"));
  *   List<LabelValue> labelValues = Arrays.asList(LabelValue.create("Inbound"));
  *
- *   // TODO(mayurkale): Plugs-in the DoubleGauge into the registry.
  *   DoubleGauge gauge = metricRegistry.addDoubleGauge("queue_size",
  *                       "Pending jobs", "1", labelKeys);
  *
@@ -86,7 +85,7 @@ public abstract class DoubleGauge {
    * method for manual operations.
    *
    * @param labelValues the list of label values. The number of label values must be the same to
-   *     that of the label keys.
+   *     that of the label keys passed to {@link MetricRegistry#addDoubleGauge}.
    * @return a {@code DoublePoint} the value of single gauge.
    * @throws NullPointerException if {@code labelValues} is null OR any element of {@code
    *     labelValues} is null.
diff --git a/api/src/main/java/io/opencensus/metrics/MetricRegistry.java b/api/src/main/java/io/opencensus/metrics/MetricRegistry.java
index 840ad787..557f886a 100644
--- a/api/src/main/java/io/opencensus/metrics/MetricRegistry.java
+++ b/api/src/main/java/io/opencensus/metrics/MetricRegistry.java
@@ -46,6 +46,23 @@ public abstract class MetricRegistry {
   public abstract LongGauge addLongGauge(
       String name, String description, String unit, List<LabelKey> labelKeys);
 
+  /**
+   * Builds a new double gauge to be added to the registry. This is more convenient form when you
+   * want to manually increase and decrease values as per your service requirements.
+   *
+   * @param name the name of the metric.
+   * @param description the description of the metric.
+   * @param unit the unit of the metric.
+   * @param labelKeys the list of the label keys.
+   * @throws NullPointerException if {@code labelKeys} is null OR any element of {@code labelKeys}
+   *     is null OR {@code name}, {@code description}, {@code unit} is null.
+   * @throws IllegalArgumentException if different metric with the same name already registered.
+   * @since 0.17
+   */
+  @ExperimentalApi
+  public abstract DoubleGauge addDoubleGauge(
+      String name, String description, String unit, List<LabelKey> labelKeys);
+
   static MetricRegistry newNoopMetricRegistry() {
     return new NoopMetricRegistry();
   }
@@ -63,5 +80,17 @@ public abstract class MetricRegistry {
           Utils.checkNotNull(unit, "unit"),
           labelKeys);
     }
+
+    @Override
+    public DoubleGauge addDoubleGauge(
+        String name, String description, String unit, List<LabelKey> labelKeys) {
+      Utils.checkListElementNotNull(
+          Utils.checkNotNull(labelKeys, "labelKeys"), "labelKey element should not be null.");
+      return DoubleGauge.newNoopDoubleGauge(
+          Utils.checkNotNull(name, "name"),
+          Utils.checkNotNull(description, "description"),
+          Utils.checkNotNull(unit, "unit"),
+          labelKeys);
+    }
   }
 }
diff --git a/api/src/test/java/io/opencensus/metrics/MetricRegistryTest.java b/api/src/test/java/io/opencensus/metrics/MetricRegistryTest.java
index 0d90fa97..2de04096 100644
--- a/api/src/test/java/io/opencensus/metrics/MetricRegistryTest.java
+++ b/api/src/test/java/io/opencensus/metrics/MetricRegistryTest.java
@@ -32,6 +32,7 @@ public class MetricRegistryTest {
   @Rule public ExpectedException thrown = ExpectedException.none();
 
   private static final String NAME = "name";
+  private static final String NAME_2 = "name2";
   private static final String DESCRIPTION = "description";
   private static final String UNIT = "1";
   private static final List<LabelKey> LABEL_KEY =
@@ -78,17 +79,60 @@ public class MetricRegistryTest {
   }
 
   @Test
+  public void noopAddDoubleGauge_NullName() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("name");
+    metricRegistry.addDoubleGauge(null, DESCRIPTION, UNIT, LABEL_KEY);
+  }
+
+  @Test
+  public void noopAddDoubleGauge_NullDescription() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("description");
+    metricRegistry.addDoubleGauge(NAME_2, null, UNIT, LABEL_KEY);
+  }
+
+  @Test
+  public void noopAddDoubleGauge_NullUnit() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("unit");
+    metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, null, LABEL_KEY);
+  }
+
+  @Test
+  public void noopAddDoubleGauge_NullLabels() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("labelKeys");
+    metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, null);
+  }
+
+  @Test
+  public void noopAddDoubleGauge_WithNullElement() {
+    List<LabelKey> labelKeys = Collections.singletonList(null);
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("labelKey element should not be null.");
+    metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, labelKeys);
+  }
+
+  @Test
   public void noopSameAs() {
     LongGauge longGauge = metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY);
     assertThat(longGauge.getDefaultTimeSeries()).isSameAs(longGauge.getDefaultTimeSeries());
     assertThat(longGauge.getDefaultTimeSeries())
         .isSameAs(longGauge.getOrCreateTimeSeries(LABEL_VALUES));
+
+    DoubleGauge doubleGauge = metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, LABEL_KEY);
+    assertThat(doubleGauge.getDefaultTimeSeries()).isSameAs(doubleGauge.getDefaultTimeSeries());
+    assertThat(doubleGauge.getDefaultTimeSeries())
+        .isSameAs(doubleGauge.getOrCreateTimeSeries(LABEL_VALUES));
   }
 
   @Test
   public void noopInstanceOf() {
-    LongGauge longGauge = metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY);
-    assertThat(longGauge)
+    assertThat(metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY))
         .isInstanceOf(LongGauge.newNoopLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY).getClass());
+    assertThat(metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, LABEL_KEY))
+        .isInstanceOf(
+            DoubleGauge.newNoopDoubleGauge(NAME_2, DESCRIPTION, UNIT, LABEL_KEY).getClass());
   }
 }
diff --git a/impl_core/src/main/java/io/opencensus/implcore/metrics/MetricRegistryImpl.java b/impl_core/src/main/java/io/opencensus/implcore/metrics/MetricRegistryImpl.java
index 8f8dab2b..c606d7e9 100644
--- a/impl_core/src/main/java/io/opencensus/implcore/metrics/MetricRegistryImpl.java
+++ b/impl_core/src/main/java/io/opencensus/implcore/metrics/MetricRegistryImpl.java
@@ -20,6 +20,7 @@ import static com.google.common.base.Preconditions.checkNotNull;
 
 import io.opencensus.common.Clock;
 import io.opencensus.implcore.internal.Utils;
+import io.opencensus.metrics.DoubleGauge;
 import io.opencensus.metrics.LabelKey;
 import io.opencensus.metrics.LongGauge;
 import io.opencensus.metrics.MetricRegistry;
@@ -57,6 +58,21 @@ public final class MetricRegistryImpl extends MetricRegistry {
     return longGaugeMetric;
   }
 
+  @Override
+  public DoubleGauge addDoubleGauge(
+      String name, String description, String unit, List<LabelKey> labelKeys) {
+    Utils.checkListElementNotNull(
+        checkNotNull(labelKeys, "labelKeys"), "labelKey element should not be null.");
+    DoubleGaugeImpl doubleGaugeMetric =
+        new DoubleGaugeImpl(
+            checkNotNull(name, "name"),
+            checkNotNull(description, "description"),
+            checkNotNull(unit, "unit"),
+            Collections.unmodifiableList(new ArrayList<LabelKey>(labelKeys)));
+    registeredMeters.registerMeter(name, doubleGaugeMetric);
+    return doubleGaugeMetric;
+  }
+
   private static final class RegisteredMeters {
     private volatile Map<String, Meter> registeredMeters = Collections.emptyMap();
 
diff --git a/impl_core/src/test/java/io/opencensus/implcore/metrics/MetricRegistryImplTest.java b/impl_core/src/test/java/io/opencensus/implcore/metrics/MetricRegistryImplTest.java
index c7cd99be..36440898 100644
--- a/impl_core/src/test/java/io/opencensus/implcore/metrics/MetricRegistryImplTest.java
+++ b/impl_core/src/test/java/io/opencensus/implcore/metrics/MetricRegistryImplTest.java
@@ -19,9 +19,12 @@ package io.opencensus.implcore.metrics;
 import static com.google.common.truth.Truth.assertThat;
 
 import io.opencensus.common.Timestamp;
+import io.opencensus.metrics.DoubleGauge;
+import io.opencensus.metrics.DoubleGauge.DoublePoint;
 import io.opencensus.metrics.LabelKey;
 import io.opencensus.metrics.LabelValue;
 import io.opencensus.metrics.LongGauge;
+import io.opencensus.metrics.LongGauge.LongPoint;
 import io.opencensus.metrics.export.Metric;
 import io.opencensus.metrics.export.MetricDescriptor;
 import io.opencensus.metrics.export.MetricDescriptor.Type;
@@ -44,6 +47,7 @@ public class MetricRegistryImplTest {
   @Rule public ExpectedException thrown = ExpectedException.none();
 
   private static final String NAME = "name";
+  private static final String NAME_2 = "name2";
   private static final String DESCRIPTION = "description";
   private static final String UNIT = "1";
   private static final List<LabelKey> LABEL_KEY =
@@ -55,8 +59,10 @@ public class MetricRegistryImplTest {
   private final TestClock testClock = TestClock.create(TEST_TIME);
   private final MetricRegistryImpl metricRegistry = new MetricRegistryImpl(testClock);
 
-  private static final MetricDescriptor METRIC_DESCRIPTOR =
+  private static final MetricDescriptor LONG_METRIC_DESCRIPTOR =
       MetricDescriptor.create(NAME, DESCRIPTION, UNIT, Type.GAUGE_INT64, LABEL_KEY);
+  private static final MetricDescriptor DOUBLE_METRIC_DESCRIPTOR =
+      MetricDescriptor.create(NAME_2, DESCRIPTION, UNIT, Type.GAUGE_DOUBLE, LABEL_KEY);
 
   @Test
   public void addLongGauge_NullName() {
@@ -95,6 +101,42 @@ public class MetricRegistryImplTest {
   }
 
   @Test
+  public void addDoubleGauge_NullName() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("name");
+    metricRegistry.addDoubleGauge(null, DESCRIPTION, UNIT, LABEL_KEY);
+  }
+
+  @Test
+  public void addDoubleGauge_NullDescription() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("description");
+    metricRegistry.addDoubleGauge(NAME_2, null, UNIT, LABEL_KEY);
+  }
+
+  @Test
+  public void addDoubleGauge_NullUnit() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("unit");
+    metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, null, LABEL_KEY);
+  }
+
+  @Test
+  public void addDoubleGauge_NullLabels() {
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("labelKeys");
+    metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, null);
+  }
+
+  @Test
+  public void addDoubleGauge_WithNullElement() {
+    List<LabelKey> labelKeys = Collections.singletonList(null);
+    thrown.expect(NullPointerException.class);
+    thrown.expectMessage("labelKey element should not be null.");
+    metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, labelKeys);
+  }
+
+  @Test
   public void addLongGauge_GetMetrics() {
     LongGauge longGauge = metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY);
     longGauge.getOrCreateTimeSeries(LABEL_VALUES);
@@ -104,19 +146,66 @@ public class MetricRegistryImplTest {
     assertThat(metricCollections)
         .containsExactly(
             Metric.createWithOneTimeSeries(
-                METRIC_DESCRIPTOR,
+                LONG_METRIC_DESCRIPTOR,
                 TimeSeries.createWithOnePoint(
                     LABEL_VALUES, Point.create(Value.longValue(0), TEST_TIME), null)));
   }
 
   @Test
+  public void addDoubleGauge_GetMetrics() {
+    DoubleGauge doubleGauge = metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, LABEL_KEY);
+    doubleGauge.getOrCreateTimeSeries(LABEL_VALUES);
+    Collection<Metric> metricCollections = metricRegistry.getMetricProducer().getMetrics();
+    assertThat(metricCollections.size()).isEqualTo(1);
+    assertThat(metricCollections)
+        .containsExactly(
+            Metric.createWithOneTimeSeries(
+                DOUBLE_METRIC_DESCRIPTOR,
+                TimeSeries.createWithOnePoint(
+                    LABEL_VALUES, Point.create(Value.doubleValue(0.0), TEST_TIME), null)));
+  }
+
+  @Test
   public void empty_GetMetrics() {
     assertThat(metricRegistry.getMetricProducer().getMetrics()).isEmpty();
   }
 
   @Test
   public void checkInstanceOf() {
+    assertThat(metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY))
+        .isInstanceOf(LongGaugeImpl.class);
+    assertThat(metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, LABEL_KEY))
+        .isInstanceOf(DoubleGaugeImpl.class);
+  }
+
+  @Test
+  public void getMetrics() {
     LongGauge longGauge = metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY);
-    assertThat(longGauge).isInstanceOf(LongGaugeImpl.class);
+    LongPoint longPoint = longGauge.getOrCreateTimeSeries(LABEL_VALUES);
+    longPoint.set(200);
+    DoubleGauge doubleGauge = metricRegistry.addDoubleGauge(NAME_2, DESCRIPTION, UNIT, LABEL_KEY);
+    DoublePoint doublePoint = doubleGauge.getOrCreateTimeSeries(LABEL_VALUES);
+    doublePoint.set(-300.13);
+
+    Collection<Metric> metricCollections = metricRegistry.getMetricProducer().getMetrics();
+    assertThat(metricCollections.size()).isEqualTo(2);
+    assertThat(metricCollections)
+        .containsExactly(
+            Metric.createWithOneTimeSeries(
+                LONG_METRIC_DESCRIPTOR,
+                TimeSeries.createWithOnePoint(
+                    LABEL_VALUES, Point.create(Value.longValue(200), TEST_TIME), null)),
+            Metric.createWithOneTimeSeries(
+                DOUBLE_METRIC_DESCRIPTOR,
+                TimeSeries.createWithOnePoint(
+                    LABEL_VALUES, Point.create(Value.doubleValue(-300.13), TEST_TIME), null)));
+  }
+
+  @Test
+  public void registerDifferentMetricSameName() {
+    metricRegistry.addLongGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY);
+    thrown.expect(IllegalArgumentException.class);
+    thrown.expectMessage("A different metric with the same name already registered.");
+    metricRegistry.addDoubleGauge(NAME, DESCRIPTION, UNIT, LABEL_KEY);
   }
 }