Allow events to be emitted with timestamp

api/events/src/main/java/io/opentelemetry/api/events/DefaultEventEmitter.java

@@ -17,6 +17,47 @@ static EventEmitter getInstance() {
     return INSTANCE;
   }
 
+  @Override
+  public void emit(long epochNanos, String eventName, Attributes attributes) {}
+
   @Override
   public void emit(String eventName, Attributes attributes) {}
+
+  @Override
+  public EventBuilder builder() {
+    return NoOpEventBuilder.INSTANCE;
+  }
+
+  @Override
+  public EventBuilder builder(String eventName) {
+    return NoOpEventBuilder.INSTANCE;
+  }
+
+  @Override
+  public EventBuilder builder(String eventName, Attributes attributes) {
+    return NoOpEventBuilder.INSTANCE;
+  }
+
+  private static class NoOpEventBuilder implements EventBuilder {
+
+    public static final EventBuilder INSTANCE = new NoOpEventBuilder();
+
+    @Override
+    public EventBuilder setEventName(String eventName) {
+      return this;
+    }
+
+    @Override
+    public EventBuilder setAttributes(Attributes attributes) {
+      return this;
+    }
+
+    @Override
+    public EventBuilder setTimestamp(long epochNanos) {
+      return this;
+    }
+
+    @Override
+    public void emit() {}
+  }
 }

api/events/src/main/java/io/opentelemetry/api/events/EventBuilder.java

@@ -0,0 +1,24 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.api.events;
+
+import io.opentelemetry.api.common.Attributes;
+
+/** The EventBuilder is used to emit() events. */
+public interface EventBuilder {
+
+  /** Set the name of the event. */
+  EventBuilder setEventName(String eventName);
+
+  /** Set the attributes to attach to the event. */
+  EventBuilder setAttributes(Attributes attributes);
+
+  /** Sets the timestamp for the event. */
+  EventBuilder setTimestamp(long epochNanos);
+
+  /** Emit an event. */
+  void emit();
+}

api/events/src/main/java/io/opentelemetry/api/events/EventEmitter.java

@@ -32,6 +32,17 @@
 @ThreadSafe
 public interface EventEmitter {
 
+  /**
+   * Emit an event.
+   *
+   * @param epochNanos The time at which the event happened, in epoch nanoseconds.
+   * @param eventName the event name, which acts as a classifier for events. Within a particular
+   *     event domain, event name defines a particular class or type of event.
+   * @param attributes attributes associated with the event
+   */
+  @SuppressWarnings("InconsistentOverloads")
+  void emit(long epochNanos, String eventName, Attributes attributes);
+
   /**
    * Emit an event.
    *
@@ -40,4 +51,10 @@ public interface EventEmitter {
    * @param attributes attributes associated with the event
    */
   void emit(String eventName, Attributes attributes);
+
+  EventBuilder builder();
+
+  EventBuilder builder(String eventName);
+
+  EventBuilder builder(String eventName, Attributes attributes);
 }

api/events/src/test/java/io/opentelemetry/api/events/DefaultEventEmitterTest.java

@@ -22,4 +22,44 @@ void emit() {
                     .emit("event-name", Attributes.builder().put("key1", "value1").build()))
         .doesNotThrowAnyException();
   }
+
+  @Test
+  void emitWithTimestamp() {
+    EventEmitter emitter = DefaultEventEmitter.getInstance();
+    Attributes attributes = Attributes.builder().put("key1", "value1").build();
+    assertThatCode(() -> emitter.emit(System.nanoTime(), "event-name", attributes))
+        .doesNotThrowAnyException();
+  }
+
+  @Test
+  void builder() {
+    Attributes attributes = Attributes.builder().put("key1", "value1").build();
+    EventEmitter emitter = DefaultEventEmitter.getInstance();
+    assertThatCode(
+            () ->
+                emitter
+                    .builder()
+                    .setEventName("myEvent")
+                    .setAttributes(attributes)
+                    .setTimestamp(123456L)
+                    .emit())
+        .doesNotThrowAnyException();
+  }
+
+  @Test
+  void builderWithName() {
+    Attributes attributes = Attributes.builder().put("key1", "value1").build();
+    EventEmitter emitter = DefaultEventEmitter.getInstance();
+    assertThatCode(
+            () -> emitter.builder("myEvent").setAttributes(attributes).setTimestamp(123456L).emit())
+        .doesNotThrowAnyException();
+  }
+
+  @Test
+  void builderWithNameAndAttrs() {
+    Attributes attributes = Attributes.builder().put("key1", "value1").build();
+    EventEmitter emitter = DefaultEventEmitter.getInstance();
+    assertThatCode(() -> emitter.builder("myEvent", attributes).setTimestamp(123456L).emit())
+        .doesNotThrowAnyException();
+  }
 }

sdk/logs/src/main/java/io/opentelemetry/sdk/logs/internal/SdkEventBuilder.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.logs.internal;
+
+import static io.opentelemetry.sdk.logs.internal.SdkEventEmitterProvider.EVENT_DOMAIN;
+import static io.opentelemetry.sdk.logs.internal.SdkEventEmitterProvider.EVENT_NAME;
+
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.events.EventBuilder;
+import io.opentelemetry.api.logs.Logger;
+import io.opentelemetry.sdk.common.Clock;
+import java.util.concurrent.TimeUnit;
+
+class SdkEventBuilder implements EventBuilder {
+  private static final String DEFAULT_EVENT_NAME = "unknown-event";
+  private final Clock clock;
+  private final Logger delegateLogger;
+  private final String eventDomain;
+
+  private String eventName = DEFAULT_EVENT_NAME;
+  private Attributes attributes = Attributes.empty();
+  private long epochNanos = Long.MIN_VALUE;
+
+  SdkEventBuilder(Clock clock, Logger delegateLogger, String eventDomain) {
+    this.clock = clock;
+    this.delegateLogger = delegateLogger;
+    this.eventDomain = eventDomain;
+  }
+
+  @Override
+  public EventBuilder setEventName(String eventName) {
+    this.eventName = eventName;
+    return this;
+  }
+
+  @Override
+  public EventBuilder setAttributes(Attributes attributes) {
+    this.attributes = attributes;
+    return this;
+  }
+
+  @Override
+  public EventBuilder setTimestamp(long epochNanos) {
+    this.epochNanos = epochNanos;
+    return this;
+  }
+
+  @Override
+  public void emit() {
+    long timestamp = epochNanos == Long.MIN_VALUE ? clock.now() : epochNanos;
+    delegateLogger
+        .logRecordBuilder()
+        .setTimestamp(timestamp, TimeUnit.NANOSECONDS)
+        .setAllAttributes(attributes)
+        .setAttribute(EVENT_DOMAIN, eventDomain)
+        .setAttribute(EVENT_NAME, eventName)
+        .emit();
+  }
+}

sdk/logs/src/main/java/io/opentelemetry/sdk/logs/internal/SdkEventEmitterProvider.java

@@ -7,14 +7,14 @@
 
 import io.opentelemetry.api.common.AttributeKey;
 import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.events.EventBuilder;
 import io.opentelemetry.api.events.EventEmitter;
 import io.opentelemetry.api.events.EventEmitterBuilder;
 import io.opentelemetry.api.events.EventEmitterProvider;
 import io.opentelemetry.api.logs.Logger;
 import io.opentelemetry.api.logs.LoggerBuilder;
 import io.opentelemetry.api.logs.LoggerProvider;
 import io.opentelemetry.sdk.common.Clock;
-import java.util.concurrent.TimeUnit;
 
 /**
  * SDK implementation for {@link EventEmitterProvider}.
@@ -24,7 +24,10 @@
  */
 public final class SdkEventEmitterProvider implements EventEmitterProvider {
 
-  private static final String DEFAULT_EVENT_DOMAIN = "unknown";
+  static final AttributeKey<String> EVENT_DOMAIN = AttributeKey.stringKey("event.domain");
+  static final AttributeKey<String> EVENT_NAME = AttributeKey.stringKey("event.name");
+
+  static final String DEFAULT_EVENT_DOMAIN = "unknown";
 
   private final LoggerProvider delegateLoggerProvider;
   private final Clock clock;
@@ -98,9 +101,6 @@ public EventEmitter build() {
 
   private static class SdkEventEmitter implements EventEmitter {
 
-    private static final AttributeKey<String> EVENT_DOMAIN = AttributeKey.stringKey("event.domain");
-    private static final AttributeKey<String> EVENT_NAME = AttributeKey.stringKey("event.name");
-
     private final Clock clock;
     private final Logger delegateLogger;
     private final String eventDomain;
@@ -111,14 +111,32 @@ private SdkEventEmitter(Clock clock, Logger delegateLogger, String eventDomain)
       this.eventDomain = eventDomain;
     }
 
+    @Override
+    public EventBuilder builder() {
+      return new SdkEventBuilder(clock, delegateLogger, eventDomain);
+    }
+
+    @Override
+    public EventBuilder builder(String eventName) {
+      return builder().setEventName(eventName);
+    }
+
+    @Override
+    public EventBuilder builder(String eventName, Attributes attributes) {
+      return builder().setEventName(eventName).setAttributes(attributes);
+    }
+
     @Override
     public void emit(String eventName, Attributes attributes) {
-      delegateLogger
-          .logRecordBuilder()
-          .setTimestamp(clock.now(), TimeUnit.NANOSECONDS)
-          .setAllAttributes(attributes)
-          .setAttribute(EVENT_DOMAIN, eventDomain)
-          .setAttribute(EVENT_NAME, eventName)
+      emit(clock.now(), eventName, attributes);
+    }
+
+    @Override
+    public void emit(long epochNanos, String eventName, Attributes attributes) {
+      new SdkEventBuilder(clock, delegateLogger, eventDomain)
+          .setTimestamp(epochNanos)
+          .setAttributes(attributes)
+          .setEventName(eventName)
           .emit();
     }
   }

sdk/logs/src/test/java/io/opentelemetry/sdk/logs/internal/SdkEventBuilderTest.java

@@ -0,0 +1,46 @@
+/*
+ * Copyright The OpenTelemetry Authors
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+package io.opentelemetry.sdk.logs.internal;
+
+import static io.opentelemetry.api.common.AttributeKey.stringKey;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyLong;
+import static org.mockito.Mockito.mock;
+import static org.mockito.Mockito.verify;
+import static org.mockito.Mockito.when;
+
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.logs.LogRecordBuilder;
+import io.opentelemetry.api.logs.Logger;
+import io.opentelemetry.sdk.common.Clock;
+import org.junit.jupiter.api.Test;
+
+class SdkEventBuilderTest {
+
+  @Test
+  void emit() {
+    String eventDomain = "mydomain";
+    String eventName = "banana";
+    Attributes attributes = Attributes.of(stringKey("foo"), "bar");
+
+    Logger logger = mock(Logger.class);
+    LogRecordBuilder logRecordBuilder = mock(LogRecordBuilder.class);
+    when(logger.logRecordBuilder()).thenReturn(logRecordBuilder);
+    when(logRecordBuilder.setTimestamp(anyLong(), any())).thenReturn(logRecordBuilder);
+    when(logRecordBuilder.setAttribute(any(), any())).thenReturn(logRecordBuilder);
+    when(logRecordBuilder.setAllAttributes(any())).thenReturn(logRecordBuilder);
+
+    new SdkEventBuilder(Clock.getDefault(), logger, eventDomain)
+        .setEventName(eventName)
+        .setTimestamp(123456L)
+        .setAttributes(attributes)
+        .emit();
+    verify(logRecordBuilder).setAllAttributes(attributes);
+    verify(logRecordBuilder).setAttribute(stringKey("event.domain"), eventDomain);
+    verify(logRecordBuilder).setAttribute(stringKey("event.name"), eventName);
+    verify(logRecordBuilder).emit();
+  }
+}