initial grpc service code in chat

service/src/test/java/org/whispersystems/textsecuregcm/grpc/EchoServiceImpl.java

@@ -0,0 +1,19 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.grpc;
+
+import io.grpc.stub.StreamObserver;
+import org.signal.chat.rpc.EchoServiceGrpc;
+import org.signal.chat.rpc.EchoRequest;
+import org.signal.chat.rpc.EchoResponse;
+
+public class EchoServiceImpl extends EchoServiceGrpc.EchoServiceImplBase {
+  @Override
+  public void echo(EchoRequest req, StreamObserver<EchoResponse> responseObserver) {
+    responseObserver.onNext(EchoResponse.newBuilder().setPayload(req.getPayload()).build());
+    responseObserver.onCompleted();
+  }
+}

service/src/test/java/org/whispersystems/textsecuregcm/grpc/UserAgentInterceptorTest.java

@@ -0,0 +1,90 @@
+/*
+ * Copyright 2023 Signal Messenger, LLC
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+package org.whispersystems.textsecuregcm.grpc;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNull;
+
+import com.google.protobuf.ByteString;
+import com.vdurmont.semver4j.Semver;
+import io.grpc.ManagedChannel;
+import io.grpc.Metadata;
+import io.grpc.Server;
+import io.grpc.inprocess.InProcessChannelBuilder;
+import io.grpc.inprocess.InProcessServerBuilder;
+import io.grpc.stub.MetadataUtils;
+import io.grpc.stub.StreamObserver;
+import org.junit.jupiter.params.ParameterizedTest;
+import org.junit.jupiter.params.provider.Arguments;
+import org.junit.jupiter.params.provider.MethodSource;
+import org.signal.chat.rpc.EchoRequest;
+import org.signal.chat.rpc.EchoResponse;
+import org.signal.chat.rpc.EchoServiceGrpc;
+import org.whispersystems.textsecuregcm.grpc.EchoServiceImpl;
+import org.whispersystems.textsecuregcm.util.ua.ClientPlatform;
+import org.whispersystems.textsecuregcm.util.ua.UserAgent;
+import org.whispersystems.textsecuregcm.util.ua.UserAgentUtil;
+
+import java.util.concurrent.atomic.AtomicReference;
+import java.util.stream.Stream;
+
+public class UserAgentInterceptorTest {
+
+  @ParameterizedTest
+  @MethodSource
+  void testInterceptor(final String header, final ClientPlatform platform, final String version) throws Exception {
+
+    final AtomicReference<UserAgent> observedUserAgent = new AtomicReference<>(null);
+    final EchoServiceImpl serviceImpl = new EchoServiceImpl() {
+        @Override
+        public void echo(EchoRequest req, StreamObserver<EchoResponse> responseObserver) {
+          observedUserAgent.set(UserAgentUtil.userAgentFromGrpcContext());
+          super.echo(req, responseObserver);
+        }
+      };
+
+    final Server testServer = InProcessServerBuilder.forName("RemoteDeprecationFilterTest")
+        .directExecutor()
+        .addService(serviceImpl)
+        .intercept(new UserAgentInterceptor())
+        .build()
+        .start();
+
+    try {
+      final ManagedChannel channel = InProcessChannelBuilder.forName("RemoteDeprecationFilterTest")
+          .directExecutor()
+          .userAgent(header)
+          .build();
+
+      final EchoServiceGrpc.EchoServiceBlockingStub client = EchoServiceGrpc.newBlockingStub(channel);
+
+      final EchoRequest req = EchoRequest.newBuilder().setPayload(ByteString.copyFromUtf8("cluck cluck, i'm a parrot")).build();
+      assertEquals("cluck cluck, i'm a parrot", client.echo(req).getPayload().toStringUtf8());
+      if (platform == null) {
+        assertNull(observedUserAgent.get());
+      } else {
+        assertEquals(platform, observedUserAgent.get().getPlatform());
+        assertEquals(new Semver(version), observedUserAgent.get().getVersion());
+        // can't assert on the additional specifiers because they include internal details of the grpc in-process channel itself
+      }
+    } finally {
+      testServer.shutdownNow();
+      testServer.awaitTermination();
+    }
+  }
+
+  private static Stream<Arguments> testInterceptor() {
+    return Stream.of(
+        Arguments.of(null, null, null),
+        Arguments.of("", null, null),
+        Arguments.of("Unrecognized UA", null, null),
+        Arguments.of("Signal-Android/4.68.3", ClientPlatform.ANDROID, "4.68.3"),
+        Arguments.of("Signal-iOS/3.9.0", ClientPlatform.IOS, "3.9.0"),
+        Arguments.of("Signal-Desktop/1.2.3", ClientPlatform.DESKTOP, "1.2.3"),
+        Arguments.of("Signal-Desktop/8.0.0-beta.2", ClientPlatform.DESKTOP, "8.0.0-beta.2"),
+        Arguments.of("Signal-iOS/8.0.0-beta.2", ClientPlatform.IOS, "8.0.0-beta.2"));
+  }
+}