Makes it possible to read commonly defined gRPC data

instrumentation/grpc/src/main/java/brave/grpc/GrpcClientRequest.java

@@ -14,7 +14,6 @@
 package brave.grpc;
 
 import brave.rpc.RpcClientRequest;
-import brave.rpc.RpcTracing;
 import io.grpc.CallOptions;
 import io.grpc.Channel;
 import io.grpc.ClientCall;
@@ -27,35 +26,19 @@
 /**
  * Allows access gRPC specific aspects of a client request during sampling and parsing.
  *
- * <p>Here's an example that adds default tags, and if gRPC, the {@linkplain
- * MethodDescriptor#getType() method type}:
- * <pre>{@code
- * Tag<GrpcClientRequest> methodType = new Tag<GrpcClientRequest>("grpc.method_type") {
- *   protected String parseValue(GrpcClientRequest input, TraceContext context) {
- *     return input.methodDescriptor().getType().name();
- *   }
- * };
- * rpcTracing = rpcTracingBuilder.clientResponseParser((res, context, span) -> {
- *   RpcResponseParser.DEFAULT.parse(res, context, span);
- *     if (res instanceof GrpcClientRequest) {
- *       methodType.tag((GrpcClientRequest) res, span);
- *     }
- *   }).build();
- * }</pre>
- *
  * @see GrpcClientResponse
- * @see RpcTracing#clientRequestParser()
+ * @see GrpcRequest for a parsing example
  * @since 5.12
  */
-public final class GrpcClientRequest extends RpcClientRequest {
+public final class GrpcClientRequest extends RpcClientRequest implements GrpcRequest {
   final Map<String, Key<String>> nameToKey;
   final MethodDescriptor<?, ?> methodDescriptor;
   final CallOptions callOptions;
   final ClientCall<?, ?> call;
   final Metadata headers;
 
   GrpcClientRequest(Map<String, Key<String>> nameToKey, MethodDescriptor<?, ?> methodDescriptor,
-    CallOptions callOptions, ClientCall<?, ?> call, Metadata headers) {
+      CallOptions callOptions, ClientCall<?, ?> call, Metadata headers) {
     if (nameToKey == null) throw new NullPointerException("nameToKey == null");
     if (methodDescriptor == null) throw new NullPointerException("methodDescriptor == null");
     if (callOptions == null) throw new NullPointerException("callOptions == null");
@@ -88,7 +71,7 @@ public final class GrpcClientRequest extends RpcClientRequest {
    *
    * @since 5.12
    */
-  public MethodDescriptor<?, ?> methodDescriptor() {
+  @Override public MethodDescriptor<?, ?> methodDescriptor() {
     return methodDescriptor;
   }
 
@@ -118,7 +101,7 @@ public CallOptions callOptions() {
    *
    * @since 5.12
    */
-  public Metadata headers() {
+  @Override public Metadata headers() {
     return headers;
   }
 

instrumentation/grpc/src/main/java/brave/grpc/GrpcClientResponse.java

@@ -15,41 +15,30 @@
 
 import brave.internal.Nullable;
 import brave.rpc.RpcClientResponse;
-import brave.rpc.RpcTracing;
 import io.grpc.ClientCall;
 import io.grpc.Metadata;
 import io.grpc.Status;
 
 /**
  * Allows access gRPC specific aspects of a client response for parsing.
  *
- * <p>Here's an example that adds default tags, and if gRPC, the Java result:
- * <pre>{@code
- * rpcTracing = rpcTracingBuilder
- *   .clientResponseParser((res, context, span) -> {
- *      RpcResponseParser.DEFAULT.parse(res, context, span);
- *      if (res instanceof DubboResponse) {
- *        DubboResponse dubboResponse = (DubboResponse) res;
- *        if (res.result() != null) {
- *          tagJavaResult(res.result().value());
- *        }
- *      }
- *   }).build();
- * }</pre>
- *
  * @see GrpcClientRequest
- * @see RpcTracing#clientResponseParser()
+ * @see GrpcResponse for a parsing example
  * @since 5.12
  */
-public final class GrpcClientResponse extends RpcClientResponse {
+public final class GrpcClientResponse extends RpcClientResponse implements GrpcResponse {
   final GrpcClientRequest request;
+  final Metadata headers;
   final Status status;
   final Metadata trailers;
 
-  GrpcClientResponse(GrpcClientRequest request, Status status, Metadata trailers) {
+  GrpcClientResponse(GrpcClientRequest request, Metadata headers, Status status,
+      Metadata trailers) {
     if (request == null) throw new NullPointerException("request == null");
+    if (headers == null) throw new NullPointerException("headers == null");
     if (status == null) throw new NullPointerException("status == null");
     if (trailers == null) throw new NullPointerException("trailers == null");
+    this.headers = headers;
     this.request = request;
     this.status = status;
     this.trailers = trailers;
@@ -78,12 +67,21 @@ public final class GrpcClientResponse extends RpcClientResponse {
     return status.getCode().name();
   }
 
+  /**
+   * Returns a copy of headers passed to {@link ClientCall.Listener#onHeaders(Metadata)}.
+   *
+   * @since 5.12
+   */
+  @Override public Metadata headers() {
+    return headers;
+  }
+
   /**
    * Returns the status passed to {@link ClientCall.Listener#onClose(Status, Metadata)}.
    *
    * @since 5.12
    */
-  public Status status() {
+  @Override public Status status() {
     return status;
   }
 
@@ -92,7 +90,7 @@ public Status status() {
    *
    * @since 5.12
    */
-  public Metadata trailers() {
+  @Override public Metadata trailers() {
     return trailers;
   }
 }

instrumentation/grpc/src/main/java/brave/grpc/GrpcRequest.java

@@ -0,0 +1,54 @@
+/*
+ * Copyright 2013-2020 The OpenZipkin Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package brave.grpc;
+
+import brave.rpc.RpcTracing;
+import io.grpc.Metadata;
+import io.grpc.MethodDescriptor;
+
+/**
+ * Allows access gRPC specific aspects of a client or server request during sampling and parsing.
+ *
+ * <p>Here's an example that adds default tags, and if gRPC, the {@linkplain
+ * MethodDescriptor#getType() method type}:
+ * <pre>{@code
+ * Tag<GrpcRequest> methodType = new Tag<GrpcRequest>("grpc.method_type") {
+ *   @Override protected String parseValue(GrpcRequest input, TraceContext context) {
+ *     return input.methodDescriptor().getType().name();
+ *   }
+ * };
+ *
+ * RpcRequestParser addMethodType = (req, context, span) -> {
+ *   RpcRequestParser.DEFAULT.parse(req, context, span);
+ *   if (req instanceof GrpcRequest) methodType.tag((GrpcRequest) req, span);
+ * };
+ *
+ * grpcTracing = GrpcTracing.create(RpcTracing.newBuilder(tracing)
+ *     .clientRequestParser(addMethodType)
+ *     .serverRequestParser(addMethodType).build());
+ * }</pre>
+ *
+ * @see GrpcResponse
+ * @see GrpcClientRequest
+ * @see GrpcServerRequest
+ * @see RpcTracing#clientRequestParser()
+ * @see RpcTracing#serverRequestParser()
+ * @since 5.12
+ */
+// NOTE: gRPC is Java 1.7+, so we cannot add methods to this later
+public interface GrpcRequest {
+  MethodDescriptor<?, ?> methodDescriptor();
+
+  Metadata headers();
+}

instrumentation/grpc/src/main/java/brave/grpc/GrpcResponse.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2013-2020 The OpenZipkin Authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
+ * in compliance with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software distributed under the License
+ * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
+ * or implied. See the License for the specific language governing permissions and limitations under
+ * the License.
+ */
+package brave.grpc;
+
+import brave.rpc.RpcTracing;
+import io.grpc.Metadata;
+import io.grpc.Status;
+
+/**
+ * Allows access gRPC specific aspects of a client or server response for parsing.
+ *
+ * <p>Here's an example that adds default tags, and if gRPC, the response encoding:
+ * <pre>{@code
+ * Tag<GrpcResponse> responseEncoding = new Tag<GrpcResponse>("grpc.response_encoding") {
+ *   @Override protected String parseValue(GrpcResponse input, TraceContext context) {
+ *     return input.headers().get(GrpcUtil.MESSAGE_ENCODING_KEY);
+ *   }
+ * };
+ *
+ * RpcResponseParser addResponseEncoding = (res, context, span) -> {
+ *   RpcResponseParser.DEFAULT.parse(res, context, span);
+ *   if (res instanceof GrpcResponse) responseEncoding.tag((GrpcResponse) res, span);
+ * };
+ *
+ * grpcTracing = GrpcTracing.create(RpcTracing.newBuilder(tracing)
+ *     .clientResponseParser(addResponseEncoding);
+ *     .serverResponseParser(addResponseEncoding).build());
+ * }</pre>
+ *
+ * @see GrpcRequest
+ * @see GrpcClientResponse
+ * @see GrpcServerResponse
+ * @see RpcTracing#clientResponseParser()
+ * @see RpcTracing#serverResponseParser()
+ * @since 5.12
+ */
+// NOTE: gRPC is Java 1.7+, so we cannot add methods to this later
+public interface GrpcResponse {
+  Metadata headers();
+
+  Status status();
+
+  Metadata trailers();
+}

instrumentation/grpc/src/main/java/brave/grpc/GrpcServerRequest.java

@@ -14,7 +14,6 @@
 package brave.grpc;
 
 import brave.rpc.RpcServerRequest;
-import brave.rpc.RpcTracing;
 import io.grpc.Metadata;
 import io.grpc.Metadata.Key;
 import io.grpc.MethodDescriptor;
@@ -25,27 +24,11 @@
 /**
  * Allows access gRPC specific aspects of a server request during sampling and parsing.
  *
- * <p>Here's an example that adds default tags, and if gRPC, the {@linkplain
- * MethodDescriptor#getType() method type}:
- * <pre>{@code
- * Tag<GrpcServerRequest> methodType = new Tag<GrpcServerRequest>("grpc.method_type") {
- *   protected String parseValue(GrpcServerRequest input, TraceContext context) {
- *     return input.call().getMethodDescriptor().getType().name();
- *   }
- * };
- * rpcTracing = rpcTracingBuilder.serverResponseParser((res, context, span) -> {
- *   RpcResponseParser.DEFAULT.parse(res, context, span);
- *     if (res instanceof GrpcServerRequest) {
- *       methodType.tag((GrpcServerRequest) res, span);
- *     }
- *   }).build();
- * }</pre>
- *
  * @see GrpcServerResponse
- * @see RpcTracing#serverRequestParser()
+ * @see GrpcRequest for a parsing example
  * @since 5.12
  */
-public class GrpcServerRequest extends RpcServerRequest {
+public class GrpcServerRequest extends RpcServerRequest implements GrpcRequest {
   final Map<String, Key<String>> nameToKey;
   final ServerCall<?, ?> call;
   final Metadata headers;
@@ -83,12 +66,21 @@ public class GrpcServerRequest extends RpcServerRequest {
     return call;
   }
 
+  /**
+   * Returns {@linkplain ServerCall#getMethodDescriptor()}} from the {@link #call()}.
+   *
+   * @since 5.12
+   */
+  @Override public MethodDescriptor<?, ?> methodDescriptor() {
+    return call.getMethodDescriptor();
+  }
+
   /**
    * Returns the {@linkplain Metadata headers} passed to {@link ServerInterceptor#interceptCall}.
    *
    * @since 5.12
    */
-  public Metadata headers() {
+  @Override public Metadata headers() {
     return headers;
   }
 

instrumentation/grpc/src/main/java/brave/grpc/GrpcServerResponse.java

@@ -15,27 +15,30 @@
 
 import brave.internal.Nullable;
 import brave.rpc.RpcServerResponse;
-import brave.rpc.RpcTracing;
 import io.grpc.Metadata;
 import io.grpc.ServerCall;
 import io.grpc.Status;
 
 /**
- * Allows access gRPC specific aspects of a client response for parsing.
+ * Allows access gRPC specific aspects of a server response for parsing.
  *
  * @see GrpcServerRequest
- * @see RpcTracing#serverResponseParser()
+ * @see GrpcResponse for a parsing example
  * @since 5.12
  */
-public final class GrpcServerResponse extends RpcServerResponse {
+public final class GrpcServerResponse extends RpcServerResponse implements GrpcResponse {
   final GrpcServerRequest request;
+  final Metadata headers;
   final Status status;
   final Metadata trailers;
 
-  GrpcServerResponse(GrpcServerRequest request, Status status, Metadata trailers) {
+  GrpcServerResponse(GrpcServerRequest request, Metadata headers, Status status,
+      Metadata trailers) {
     if (request == null) throw new NullPointerException("request == null");
+    if (headers == null) throw new NullPointerException("headers == null");
     if (status == null) throw new NullPointerException("status == null");
     if (trailers == null) throw new NullPointerException("trailers == null");
+    this.headers = headers;
     this.request = request;
     this.status = status;
     this.trailers = trailers;
@@ -65,11 +68,20 @@ public final class GrpcServerResponse extends RpcServerResponse {
   }
 
   /**
-   * Returns the status passed to{@link ServerCall#close(Status, Metadata)}.
+   * Returns a copy of headers passed to {@link ServerCall#sendHeaders(Metadata)}.
    *
    * @since 5.12
    */
-  public Status status() {
+  @Override public Metadata headers() {
+    return headers;
+  }
+
+  /**
+   * Returns the status passed to {@link ServerCall#close(Status, Metadata)}.
+   *
+   * @since 5.12
+   */
+  @Override public Status status() {
     return status;
   }
 
@@ -78,7 +90,7 @@ public Status status() {
    *
    * @since 5.12
    */
-  public Metadata trailers() {
+  @Override public Metadata trailers() {
     return trailers;
   }
 }