Add support for gRPC Batch API

pom.xml

@@ -72,6 +72,10 @@
     <oauth2-oidc-sdk.version>10.14.2</oauth2-oidc-sdk.version>
     <mock-server.version>5.15.0</mock-server.version>
     <jackson.version>2.15.2</jackson.version>
+    <grpc-netty-shaded.version>1.58.0</grpc-netty-shaded.version>
+    <grpc-protobuf.version>1.58.0</grpc-protobuf.version>
+    <grpc-stub.version>1.58.0</grpc-stub.version>
+    <annotations-api.version>6.0.53</annotations-api.version>
   </properties>
 
   <dependencies>
@@ -100,6 +104,28 @@
       <artifactId>oauth2-oidc-sdk</artifactId>
       <version>${oauth2-oidc-sdk.version}</version>
     </dependency>
+    <dependency>
+      <groupId>io.grpc</groupId>
+      <artifactId>grpc-netty-shaded</artifactId>
+      <version>${grpc-netty-shaded.version}</version>
+      <scope>runtime</scope>
+    </dependency>
+    <dependency>
+      <groupId>io.grpc</groupId>
+      <artifactId>grpc-protobuf</artifactId>
+      <version>${grpc-protobuf.version}</version>
+    </dependency>
+    <dependency>
+      <groupId>io.grpc</groupId>
+      <artifactId>grpc-stub</artifactId>
+      <version>${grpc-stub.version}</version>
+    </dependency>
+    <dependency> <!-- necessary for Java 9+ -->
+      <groupId>org.apache.tomcat</groupId>
+      <artifactId>annotations-api</artifactId>
+      <version>${annotations-api.version}</version>
+      <scope>provided</scope>
+    </dependency>
     <dependency>
       <groupId>org.junit.jupiter</groupId>
       <artifactId>junit-jupiter-api</artifactId>
@@ -157,6 +183,13 @@
   </dependencies>
 
   <build>
+    <extensions>
+      <extension>
+        <groupId>kr.motd.maven</groupId>
+        <artifactId>os-maven-plugin</artifactId>
+        <version>1.7.1</version>
+      </extension>
+    </extensions>
     <pluginManagement>
       <plugins>
         <plugin>
@@ -346,6 +379,24 @@
           <artifactId>maven-project-info-reports-plugin</artifactId>
           <version>3.1.1</version>
         </plugin>
+        <plugin>
+          <groupId>org.xolstice.maven.plugins</groupId>
+          <artifactId>protobuf-maven-plugin</artifactId>
+          <version>0.6.1</version>
+          <configuration>
+            <protocArtifact>com.google.protobuf:protoc:3.24.0:exe:${os.detected.classifier}</protocArtifact>
+            <pluginId>grpc-java</pluginId>
+            <pluginArtifact>io.grpc:protoc-gen-grpc-java:1.58.0:exe:${os.detected.classifier}</pluginArtifact>
+          </configuration>
+          <executions>
+            <execution>
+              <goals>
+                <goal>compile</goal>
+                <goal>compile-custom</goal>
+              </goals>
+            </execution>
+          </executions>
+        </plugin>
       </plugins>
     </pluginManagement>
     <plugins>
@@ -373,6 +424,10 @@
         <groupId>org.sonatype.plugins</groupId>
         <artifactId>nexus-staging-maven-plugin</artifactId>
       </plugin>
+<!--      <plugin>-->
+<!--        <groupId>org.xolstice.maven.plugins</groupId>-->
+<!--        <artifactId>protobuf-maven-plugin</artifactId>-->
+<!--      </plugin>-->
     </plugins>
   </build>
 </project>

src/main/java/io/weaviate/client/Config.java

@@ -1,10 +1,12 @@
 package io.weaviate.client;
 
 import java.util.Map;
+import lombok.Getter;
 
 public class Config {
 
   private static final int DEFAULT_TIMEOUT_SECONDS = 60;
+  @Getter
   private final String scheme;
   private final String host;
   private final String version;
@@ -15,6 +17,9 @@ public class Config {
   private String proxyHost;
   private int proxyPort;
   private String proxyScheme;
+  private boolean useGRPC;
+  @Getter
+  private String grpcAddress;
 
 
   public Config(String scheme, String host) {
@@ -35,10 +40,25 @@ public Config(String scheme, String host, Map<String, String> headers, int conne
     this.socketTimeout = socketTimeout;
   }
 
+  public Config(String scheme, String host, Map<String, String> headers, int timeout, boolean useGRPC) {
+    this.scheme = scheme;
+    this.host = host;
+    this.version = "v1";
+    this.headers = headers;
+    this.connectionTimeout = timeout;
+    this.connectionRequestTimeout = timeout;
+    this.socketTimeout = timeout;
+    this.useGRPC = useGRPC;
+  }
+
   public String getBaseURL() {
     return scheme + "://" + host + "/" + version;
   }
 
+  public String getHost() {
+    return host;
+  }
+
   public Map<String, String> getHeaders() {
     return headers;
   }
@@ -72,5 +92,16 @@ public int getProxyPort() {
   public String getProxyScheme() {
     return proxyScheme;
   }
-
+
+  public boolean useGRPC() {
+    return this.useGRPC;
+  }
+
+  public void setUseGRPC(boolean useGRPC) {
+    this.useGRPC = useGRPC;
+  }
+
+  public void setGrpcAddress(String grpcAddress) {
+    this.grpcAddress = grpcAddress;
+  }
 }

src/main/java/io/weaviate/client/grpc/client/GrpcClient.java

@@ -0,0 +1,38 @@
+package io.weaviate.client.grpc.client;
+
+import io.grpc.ManagedChannel;
+import io.grpc.ManagedChannelBuilder;
+import io.grpc.Metadata;
+import io.grpc.stub.MetadataUtils;
+import io.weaviate.client.Config;
+import io.weaviate.client.grpc.protocol.WeaviateGrpc;
+import java.util.Map;
+
+public class GrpcClient {
+
+  public static WeaviateGrpc.WeaviateBlockingStub create(Config config) {
+    Metadata headers = new Metadata();
+    if (config.getHeaders() != null) {
+      for (Map.Entry<String, String> e : config.getHeaders().entrySet()) {
+        headers.put(Metadata.Key.of(e.getKey(), Metadata.ASCII_STRING_MARSHALLER), e.getValue());
+      }
+    }
+    ManagedChannel channel = ManagedChannelBuilder.forTarget(getAddress(config)).usePlaintext().build();
+    WeaviateGrpc.WeaviateBlockingStub blockingStub = WeaviateGrpc.newBlockingStub(channel);
+    return blockingStub.withInterceptors(MetadataUtils.newAttachHeadersInterceptor(headers));
+  }
+
+  private static String getAddress(Config config) {
+    if (config.getGrpcAddress() != null) {
+      return config.getGrpcAddress();
+    }
+    String host = config.getHost();
+    if (!host.contains(":")) {
+      if (config.getScheme() != null && config.getScheme().equals("https")) {
+        return String.format("%s:443", host);
+      }
+      return String.format("%s:80", host);
+    }
+    return host;
+  }
+}