Stabilize synchronous gauge

api/all/src/main/java/io/opentelemetry/api/metrics/DefaultMeter.java

@@ -320,8 +320,10 @@ public LongHistogram build() {
   }
 
   private static class NoopDoubleGaugeBuilder implements DoubleGaugeBuilder {
-    private static final ObservableDoubleGauge NOOP = new ObservableDoubleGauge() {};
+    private static final ObservableDoubleGauge NOOP_OBSERVABLE_GAUGE =
+        new ObservableDoubleGauge() {};
     private static final LongGaugeBuilder NOOP_LONG_GAUGE_BUILDER = new NoopLongGaugeBuilder();
+    private static final NoopDoubleGauge NOOP_GAUGE = new NoopDoubleGauge();
 
     @Override
     public DoubleGaugeBuilder setDescription(String description) {
@@ -340,17 +342,34 @@ public LongGaugeBuilder ofLongs() {
 
     @Override
     public ObservableDoubleGauge buildWithCallback(Consumer<ObservableDoubleMeasurement> callback) {
-      return NOOP;
+      return NOOP_OBSERVABLE_GAUGE;
     }
 
     @Override
     public ObservableDoubleMeasurement buildObserver() {
       return NOOP_OBSERVABLE_DOUBLE_MEASUREMENT;
     }
+
+    @Override
+    public DoubleGauge build() {
+      return NOOP_GAUGE;
+    }
+  }
+
+  private static class NoopDoubleGauge implements DoubleGauge {
+    @Override
+    public void set(double value) {}
+
+    @Override
+    public void set(double value, Attributes attributes) {}
+
+    @Override
+    public void set(double value, Attributes attributes, Context context) {}
   }
 
   private static class NoopLongGaugeBuilder implements LongGaugeBuilder {
-    private static final ObservableLongGauge NOOP = new ObservableLongGauge() {};
+    private static final ObservableLongGauge NOOP_OBSERVABLE_GAUGE = new ObservableLongGauge() {};
+    private static final NoopLongGauge NOOP_GAUGE = new NoopLongGauge();
 
     @Override
     public LongGaugeBuilder setDescription(String description) {
@@ -364,13 +383,29 @@ public LongGaugeBuilder setUnit(String unit) {
 
     @Override
     public ObservableLongGauge buildWithCallback(Consumer<ObservableLongMeasurement> callback) {
-      return NOOP;
+      return NOOP_OBSERVABLE_GAUGE;
     }
 
     @Override
     public ObservableLongMeasurement buildObserver() {
       return NOOP_OBSERVABLE_LONG_MEASUREMENT;
     }
+
+    @Override
+    public LongGauge build() {
+      return NOOP_GAUGE;
+    }
+  }
+
+  private static class NoopLongGauge implements LongGauge {
+    @Override
+    public void set(long value) {}
+
+    @Override
+    public void set(long value, Attributes attributes) {}
+
+    @Override
+    public void set(long value, Attributes attributes, Context context) {}
   }
 
   private static class NoopObservableDoubleMeasurement implements ObservableDoubleMeasurement {

api/incubator/src/main/java/io/opentelemetry/api/incubator/metrics/DoubleGauge.java → api/all/src/main/java/io/opentelemetry/api/metrics/DoubleGauge.java

@@ -3,9 +3,10 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.api.incubator.metrics;
+package io.opentelemetry.api.metrics;
 
 import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.context.Context;
 import javax.annotation.concurrent.ThreadSafe;
 
 /** A gauge instrument that synchronously records {@code double} values. */
@@ -26,5 +27,12 @@ public interface DoubleGauge {
    */
   void set(double value, Attributes attributes);
 
-  // TODO(jack-berg): should we add overload with Context argument?
+  /**
+   * Records a value with a set of attributes.
+   *
+   * @param value The current gauge value.
+   * @param attributes A set of attributes to associate with the value.
+   * @param context The explicit context to associate with this measurement.
+   */
+  void set(double value, Attributes attributes, Context context);
 }

api/all/src/main/java/io/opentelemetry/api/metrics/DoubleGaugeBuilder.java

@@ -65,4 +65,17 @@
   default ObservableDoubleMeasurement buildObserver() {
     return DefaultMeter.getInstance().gaugeBuilder("noop").buildObserver();
   }
+
+  /**
+   * Builds and returns a DoubleGauge instrument with the configuration.
+   *
+   * <p>NOTE: This produces a synchronous gauge which records gauge values as they occur. Most users
+   * will want to instead register an {@link #buildWithCallback(Consumer)} to asynchronously observe
+   * the value of the gauge when metrics are collected.
+   *
+   * @return The DoubleGauge instrument.
+   */
+  default DoubleGauge build() {
+    return DefaultMeter.getInstance().gaugeBuilder("noop").build();
+  }
 }

api/incubator/src/main/java/io/opentelemetry/api/incubator/metrics/LongGauge.java → api/all/src/main/java/io/opentelemetry/api/metrics/LongGauge.java

@@ -3,9 +3,10 @@
  * SPDX-License-Identifier: Apache-2.0
  */
 
-package io.opentelemetry.api.incubator.metrics;
+package io.opentelemetry.api.metrics;
 
 import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.context.Context;
 import javax.annotation.concurrent.ThreadSafe;
 
 /** A gauge instrument that synchronously records {@code long} values. */
@@ -26,5 +27,12 @@ public interface LongGauge {
    */
   void set(long value, Attributes attributes);
 
-  // TODO(jack-berg): should we add overload with Context argument?
+  /**
+   * Records a value with a set of attributes.
+   *
+   * @param value The current gauge value.
+   * @param attributes A set of attributes to associate with the value.
+   * @param context The explicit context to associate with this measurement.
+   */
+  void set(long value, Attributes attributes, Context context);
 }

api/all/src/main/java/io/opentelemetry/api/metrics/LongGaugeBuilder.java

@@ -62,4 +62,17 @@
   default ObservableLongMeasurement buildObserver() {
     return DefaultMeter.getInstance().gaugeBuilder("noop").ofLongs().buildObserver();
   }
+
+  /**
+   * Builds and returns a LongGauge instrument with the configuration.
+   *
+   * <p>NOTE: This produces a synchronous gauge which records gauge values as they occur. Most users
+   * will want to instead register an {@link #buildWithCallback(Consumer)} to asynchronously observe
+   * the value of the gauge when metrics are collected.
+   *
+   * @return The LongGauge instrument.
+   */
+  default LongGauge build() {
+    return DefaultMeter.getInstance().gaugeBuilder("noop").ofLongs().build();
+  }
 }

api/all/src/test/java/io/opentelemetry/api/metrics/DefaultMeterTest.java

@@ -93,6 +93,20 @@ void noopDoubleHistogram_doesNotThrow() {
     histogram.record(1.0e-1, Attributes.of(stringKey("thing"), "car"), Context.current());
   }
 
+  @Test
+  void noopLongGauage_doesNotThrow() {
+    LongGauge gauge =
+        METER
+            .gaugeBuilder("temperature")
+            .ofLongs()
+            .setDescription("The current temperature")
+            .setUnit("C")
+            .build();
+    gauge.set(1);
+    gauge.set(2, Attributes.of(stringKey("thing"), "engine"));
+    gauge.set(2, Attributes.of(stringKey("thing"), "engine"), Context.current());
+  }
+
   @Test
   void noopObservableLongGauage_doesNotThrow() {
     METER
@@ -107,6 +121,19 @@ void noopObservableLongGauage_doesNotThrow() {
             });
   }
 
+  @Test
+  void noopDoubleGauage_doesNotThrow() {
+    DoubleGauge gauge =
+        METER
+            .gaugeBuilder("temperature")
+            .setDescription("The current temperature")
+            .setUnit("C")
+            .build();
+    gauge.set(1);
+    gauge.set(2, Attributes.of(stringKey("thing"), "engine"));
+    gauge.set(2, Attributes.of(stringKey("thing"), "engine"), Context.current());
+  }
+
   @Test
   void noopObservableDoubleGauage_doesNotThrow() {
     METER

api/incubator/src/main/java/io/opentelemetry/api/incubator/metrics/ExtendedDoubleGaugeBuilder.java

@@ -8,22 +8,10 @@
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.metrics.DoubleGaugeBuilder;
 import java.util.List;
-import java.util.function.Consumer;
 
 /** Extended {@link DoubleGaugeBuilder} with experimental APIs. */
 public interface ExtendedDoubleGaugeBuilder extends DoubleGaugeBuilder {
 
-  /**
-   * Builds and returns a DoubleGauge instrument with the configuration.
-   *
-   * <p>NOTE: This produces a synchronous gauge which records gauge values as they occur. Most users
-   * will want to instead register an {@link #buildWithCallback(Consumer)} to asynchronously observe
-   * the value of the gauge when metrics are collected.
-   *
-   * @return The DoubleGauge instrument.
-   */
-  DoubleGauge build();
-
   /**
    * Specify the attribute advice, which suggests the recommended set of attribute keys to be used
    * for this gauge.

api/incubator/src/main/java/io/opentelemetry/api/incubator/metrics/ExtendedLongGaugeBuilder.java

@@ -8,22 +8,10 @@
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.metrics.LongGaugeBuilder;
 import java.util.List;
-import java.util.function.Consumer;
 
 /** Extended {@link LongGaugeBuilder} with experimental APIs. */
 public interface ExtendedLongGaugeBuilder extends LongGaugeBuilder {
 
-  /**
-   * Builds and returns a LongGauge instrument with the configuration.
-   *
-   * <p>NOTE: This produces a synchronous gauge which records gauge values as they occur. Most users
-   * will want to instead register an {@link #buildWithCallback(Consumer)} to asynchronously observe
-   * the value of the gauge when metrics are collected.
-   *
-   * @return The LongGauge instrument.
-   */
-  LongGauge build();
-
   /**
    * Specify the attribute advice, which suggests the recommended set of attribute keys to be used
    * for this gauge.

api/incubator/src/test/java/io/opentelemetry/api/incubator/metrics/ExtendedMetricsApiUsageTest.java

@@ -23,48 +23,6 @@
 /** Demonstrating usage of extended Metrics API. */
 class ExtendedMetricsApiUsageTest {
 
-  @Test
-  void synchronousGaugeUsage() {
-    // Setup SdkMeterProvider
-    InMemoryMetricReader reader = InMemoryMetricReader.create();
-    SdkMeterProvider meterProvider =
-        SdkMeterProvider.builder()
-            // Default resource used for demonstration purposes
-            .setResource(Resource.getDefault())
-            // In-memory reader used for demonstration purposes
-            .registerMetricReader(reader)
-            .build();
-
-    // Get a Meter for a scope
-    Meter meter = meterProvider.get("org.foo.my-scope");
-
-    // Cast GaugeBuilder to ExtendedDoubleGaugeBuilder
-    DoubleGauge gauge = ((ExtendedDoubleGaugeBuilder) meter.gaugeBuilder("my-gauge")).build();
-
-    // Call set synchronously to set the value
-    gauge.set(1.0, Attributes.builder().put("key", "value1").build());
-    gauge.set(2.0, Attributes.builder().put("key", "value2").build());
-
-    assertThat(reader.collectAllMetrics())
-        .satisfiesExactly(
-            metricData ->
-                assertThat(metricData)
-                    .hasName("my-gauge")
-                    .hasDoubleGaugeSatisfying(
-                        gaugeAssert ->
-                            gaugeAssert.hasPointsSatisfying(
-                                point ->
-                                    point
-                                        .hasValue(1.0)
-                                        .hasAttributes(
-                                            Attributes.builder().put("key", "value1").build()),
-                                point ->
-                                    point
-                                        .hasValue(2.0)
-                                        .hasAttributes(
-                                            Attributes.builder().put("key", "value2").build()))));
-  }
-
   @Test
   void attributesAdvice() {
     // Setup SdkMeterProvider

docs/apidiffs/current_vs_latest/opentelemetry-api.txt

@@ -1,2 +1,19 @@
 Comparing source compatibility of  against 
-No changes.
++++  NEW INTERFACE: PUBLIC(+) ABSTRACT(+) io.opentelemetry.api.metrics.DoubleGauge  (not serializable)
+	+++  CLASS FILE FORMAT VERSION: 52.0 <- n.a.
+	+++  NEW SUPERCLASS: java.lang.Object
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) void set(double)
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) void set(double, io.opentelemetry.api.common.Attributes)
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) void set(double, io.opentelemetry.api.common.Attributes, io.opentelemetry.context.Context)
+***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.api.metrics.DoubleGaugeBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.api.metrics.DoubleGauge build()
++++  NEW INTERFACE: PUBLIC(+) ABSTRACT(+) io.opentelemetry.api.metrics.LongGauge  (not serializable)
+	+++  CLASS FILE FORMAT VERSION: 52.0 <- n.a.
+	+++  NEW SUPERCLASS: java.lang.Object
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) void set(long)
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) void set(long, io.opentelemetry.api.common.Attributes)
+	+++  NEW METHOD: PUBLIC(+) ABSTRACT(+) void set(long, io.opentelemetry.api.common.Attributes, io.opentelemetry.context.Context)
+***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.api.metrics.LongGaugeBuilder  (not serializable)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW METHOD: PUBLIC(+) io.opentelemetry.api.metrics.LongGauge build()

docs/apidiffs/current_vs_latest/opentelemetry-sdk-metrics.txt

@@ -5,3 +5,6 @@ Comparing source compatibility of  against
 ***  MODIFIED INTERFACE: PUBLIC ABSTRACT io.opentelemetry.sdk.metrics.export.DefaultAggregationSelector  (not serializable)
 	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
 	+++  NEW METHOD: PUBLIC(+) STATIC(+) java.lang.String asString(io.opentelemetry.sdk.metrics.export.DefaultAggregationSelector)
+***  MODIFIED ENUM: PUBLIC FINAL io.opentelemetry.sdk.metrics.InstrumentType  (compatible)
+	===  CLASS FILE FORMAT VERSION: 52.0 <- 52.0
+	+++  NEW FIELD: PUBLIC(+) STATIC(+) FINAL(+) io.opentelemetry.sdk.metrics.InstrumentType GAUGE

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/InstrumentType.java

@@ -17,4 +17,5 @@ public enum InstrumentType {
   OBSERVABLE_COUNTER,
   OBSERVABLE_UP_DOWN_COUNTER,
   OBSERVABLE_GAUGE,
+  GAUGE,
 }

sdk/metrics/src/main/java/io/opentelemetry/sdk/metrics/SdkDoubleGauge.java

@@ -7,8 +7,8 @@
 
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.common.Attributes;
-import io.opentelemetry.api.incubator.metrics.DoubleGauge;
 import io.opentelemetry.api.incubator.metrics.ExtendedDoubleGaugeBuilder;
+import io.opentelemetry.api.metrics.DoubleGauge;
 import io.opentelemetry.api.metrics.DoubleGaugeBuilder;
 import io.opentelemetry.api.metrics.LongGaugeBuilder;
 import io.opentelemetry.api.metrics.ObservableDoubleGauge;
@@ -31,8 +31,13 @@
   }
 
   @Override
-  public void set(double increment, Attributes attributes) {
-    storage.recordDouble(increment, attributes, Context.root());
+  public void set(double value, Attributes attributes) {
+    storage.recordDouble(value, attributes, Context.current());
+  }
+
+  @Override
+  public void set(double value, Attributes attributes, Context context) {
+    storage.recordDouble(value, attributes, context);
   }
 
   @Override
@@ -48,11 +53,10 @@
         MeterSharedState meterSharedState,
         String name) {
 
-      // TODO: use InstrumentType.GAUGE when available
       builder =
           new InstrumentBuilder(
               name,
-              InstrumentType.OBSERVABLE_GAUGE,
+              InstrumentType.GAUGE,
               InstrumentValueType.DOUBLE,
               meterProviderSharedState,
               meterSharedState);
@@ -88,13 +92,11 @@
 
     @Override
     public ObservableDoubleGauge buildWithCallback(Consumer<ObservableDoubleMeasurement> callback) {
-      // TODO: use InstrumentType.GAUGE when available
       return builder.buildDoubleAsynchronousInstrument(InstrumentType.OBSERVABLE_GAUGE, callback);
     }
 
     @Override
     public ObservableDoubleMeasurement buildObserver() {
-      // TODO: use InstrumentType.GAUGE when available
       return builder.buildObservableMeasurement(InstrumentType.OBSERVABLE_GAUGE);
     }