add rpc metrics conventions implement

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/rpc/MetricsView.java

@@ -0,0 +1,59 @@
+package io.opentelemetry.instrumentation.api.instrumenter.rpc;
+
+import io.opentelemetry.api.common.AttributeKey;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.common.AttributesBuilder;
+import io.opentelemetry.semconv.trace.attributes.SemanticAttributes;
+import java.util.HashSet;
+import java.util.Set;
+import java.util.function.BiConsumer;
+
+/**
+ * filter rpc metrics unnecessary attributes.
+ */
+public class MetricsView {
+
+  private static final Set<AttributeKey> recommended = buildRecommended();
+  private static final Set<AttributeKey> optional = buildOptional();
+
+  private static Set<AttributeKey> buildRecommended() {
+    // the list of Recommended metrics attributes is from
+    // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#attributes
+    Set<AttributeKey> view = new HashSet<>();
+    view.add(SemanticAttributes.RPC_SYSTEM);
+    view.add(SemanticAttributes.RPC_SERVICE);
+    view.add(SemanticAttributes.RPC_METHOD);
+    return view;
+  }
+
+  private static Set<AttributeKey> buildOptional() {
+    // the list of Recommended metrics attributes is from
+    // https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#attributes
+    Set<AttributeKey> view = new HashSet<>();
+    view.add(SemanticAttributes.NET_PEER_IP);
+    view.add(SemanticAttributes.NET_PEER_NAME);
+    view.add(SemanticAttributes.NET_PEER_PORT);
+    view.add(SemanticAttributes.NET_TRANSPORT);
+    return view;
+  }
+
+  static Attributes applyRpcView(Attributes startAttributes, Attributes endAttributes) {
+    Attributes attributes = startAttributes.toBuilder().putAll(endAttributes).build();
+    AttributesBuilder filtered = Attributes.builder();
+    applyView(filtered, attributes, recommended);
+    applyView(filtered, attributes, optional);
+    return filtered.build();
+  }
+
+  @SuppressWarnings("unchecked")
+  private static void applyView(
+      AttributesBuilder filtered, Attributes attributes, Set<AttributeKey> view) {
+    attributes.forEach(
+        (BiConsumer<AttributeKey, Object>)
+            (key, value) -> {
+              if (view.contains(key)) {
+                filtered.put(key, value);
+              }
+            });
+  }
+}

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/rpc/RpcClientMetrics.java

@@ -0,0 +1,77 @@
+package io.opentelemetry.instrumentation.api.instrumenter.rpc;
+
+import com.google.auto.value.AutoValue;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.metrics.LongHistogram;
+import io.opentelemetry.api.metrics.Meter;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.ContextKey;
+import io.opentelemetry.instrumentation.api.annotations.UnstableApi;
+import io.opentelemetry.instrumentation.api.instrumenter.RequestListener;
+import io.opentelemetry.instrumentation.api.instrumenter.RequestMetrics;
+import java.util.concurrent.TimeUnit;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * guide from https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#rpc-client
+ */
+@UnstableApi
+public class RpcClientMetrics implements RequestListener {
+
+  private static final ContextKey<RpcClientMetrics.State> RPC_CLIENT_REQUEST_METRICS_STATE =
+      ContextKey.named("rpc-client-request-metrics-state");
+
+  private static final Logger logger = LoggerFactory.getLogger(RpcClientMetrics.class);
+
+  /**
+   * measures duration of outbound RPC.
+   */
+  private final LongHistogram clientDurationHistogram;
+
+  private RpcClientMetrics(Meter meter) {
+    clientDurationHistogram = meter
+        .histogramBuilder("rpc.client.duration")
+        .setDescription("measures duration of outbound RPC")
+        .setUnit("milliseconds")
+        .ofLongs().build();
+  }
+
+  /**
+   * Returns a {@link RequestMetrics} which can be used to enable recording of {@link
+   * RpcClientMetrics} on an {@link
+   * io.opentelemetry.instrumentation.api.instrumenter.InstrumenterBuilder}
+   * method addRequestMetrics().
+   */
+  @UnstableApi
+  public static RequestMetrics get() {
+    return RpcClientMetrics::new;
+  }
+
+  @Override
+  public Context start(Context context, Attributes startAttributes, long startNanos) {
+    return context.with(RPC_CLIENT_REQUEST_METRICS_STATE,
+        new AutoValue_RpcClientMetrics_State(startAttributes, startNanos));
+  }
+
+  @Override
+  public void end(Context context, Attributes endAttributes, long endNanos) {
+    State state = context.get(RPC_CLIENT_REQUEST_METRICS_STATE);
+    if (state == null) {
+      logger.debug(
+          "No state present when ending context {}. Cannot reset RPC request metrics.", context);
+    }
+    clientDurationHistogram.record(
+        TimeUnit.MILLISECONDS.convert(
+            endNanos - state.startTimeNanos(), TimeUnit.NANOSECONDS),
+        MetricsView.applyRpcView(state.startAttributes(), endAttributes), context);
+  }
+
+  @AutoValue
+  abstract static class State {
+
+    abstract Attributes startAttributes();
+
+    abstract long startTimeNanos();
+  }
+}

instrumentation-api/src/main/java/io/opentelemetry/instrumentation/api/instrumenter/rpc/RpcServerMetrics.java

@@ -0,0 +1,80 @@
+package io.opentelemetry.instrumentation.api.instrumenter.rpc;
+
+import com.google.auto.value.AutoValue;
+import io.opentelemetry.api.common.Attributes;
+import io.opentelemetry.api.metrics.LongHistogram;
+import io.opentelemetry.api.metrics.Meter;
+import io.opentelemetry.context.Context;
+import io.opentelemetry.context.ContextKey;
+import io.opentelemetry.instrumentation.api.annotations.UnstableApi;
+import io.opentelemetry.instrumentation.api.instrumenter.RequestListener;
+import io.opentelemetry.instrumentation.api.instrumenter.RequestMetrics;
+import java.util.concurrent.TimeUnit;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * guide from https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/metrics/semantic_conventions/rpc.md#rpc-server
+ */
+@UnstableApi
+public class RpcServerMetrics implements RequestListener {
+
+  private static final ContextKey<RpcServerMetrics.State> RPC_SERVER_REQUEST_METRICS_STATE =
+      ContextKey.named("rpc-server-request-metrics-state");
+
+  private static final Logger logger = LoggerFactory.getLogger(RpcServerMetrics.class);
+
+  /**
+   * measures duration of inbound RPC.
+   */
+  private final LongHistogram serverDurationHistogram;
+
+  private RpcServerMetrics(Meter meter) {
+    serverDurationHistogram = meter
+        .histogramBuilder("rpc.server.duration")
+        .setDescription("measures duration of inbound RPC")
+        .setUnit("milliseconds")
+        .ofLongs().build();
+  }
+
+  /**
+   * Returns a {@link RequestMetrics} which can be used to enable recording of {@link
+   * RpcServerMetrics} on an {@link
+   * io.opentelemetry.instrumentation.api.instrumenter.InstrumenterBuilder}
+   * method addRequestMetrics().
+   */
+  @UnstableApi
+  public static RequestMetrics get() {
+    return RpcServerMetrics::new;
+  }
+
+  @Override
+  public Context start(Context context, Attributes startAttributes, long startNanos) {
+    return context.with(RPC_SERVER_REQUEST_METRICS_STATE,
+        new AutoValue_RpcServerMetrics_State(startAttributes, startNanos));
+  }
+
+  @Override
+  public void end(Context context, Attributes endAttributes, long endNanos) {
+    State state = context.get(RPC_SERVER_REQUEST_METRICS_STATE);
+    if (state == null) {
+      logger.debug(
+          "No state present when ending context {}. Cannot reset RPC request metrics.", context);
+    }
+    serverDurationHistogram.record(
+        TimeUnit.MILLISECONDS.convert(
+            endNanos - state.startTimeNanos(), TimeUnit.NANOSECONDS),
+        MetricsView.applyRpcView(state.startAttributes(), endAttributes), context);
+  }
+
+  @AutoValue
+  abstract static class State {
+
+    abstract Attributes startAttributes();
+
+    abstract long startTimeNanos();
+
+  }
+}
+
+