Support Dapr API token in workflow client

sdk-workflows/src/main/java/io/dapr/workflows/client/DaprWorkflowClient.java

@@ -17,9 +17,18 @@
 import com.microsoft.durabletask.DurableTaskGrpcClientBuilder;
 import com.microsoft.durabletask.OrchestrationMetadata;
 import com.microsoft.durabletask.PurgeResult;
+import io.dapr.client.Headers;
+import io.dapr.config.Properties;
 import io.dapr.utils.NetworkUtils;
 import io.dapr.workflows.Workflow;
+import io.grpc.CallOptions;
+import io.grpc.Channel;
+import io.grpc.ClientCall;
+import io.grpc.ClientInterceptor;
+import io.grpc.ForwardingClientCall;
 import io.grpc.ManagedChannel;
+import io.grpc.Metadata;
+import io.grpc.MethodDescriptor;
 
 import javax.annotation.Nullable;
 
@@ -39,7 +48,7 @@ public class DaprWorkflowClient implements AutoCloseable {
    * Public constructor for DaprWorkflowClient. This layer constructs the GRPC Channel.
    */
   public DaprWorkflowClient() {
-    this(NetworkUtils.buildGrpcManagedChannel());
+    this(NetworkUtils.buildGrpcManagedChannel(WORKFLOW_INTERCEPTOR));
   }
 
   /**
@@ -239,4 +248,26 @@ public void close() throws InterruptedException {
       }
     }
   }
+
+  private static ClientInterceptor WORKFLOW_INTERCEPTOR = new ClientInterceptor() {
+    @Override
+    public <ReqT, RespT> ClientCall<ReqT, RespT> interceptCall(
+        MethodDescriptor<ReqT, RespT> methodDescriptor,
+        CallOptions options,
+        Channel channel) {
+      // TBD: do we need timeout in workflow client?
+      ClientCall<ReqT, RespT> clientCall = channel.newCall(methodDescriptor, options);
+      return new ForwardingClientCall.SimpleForwardingClientCall<ReqT, RespT>(clientCall) {
+        @Override
+        public void start(final Listener<RespT> responseListener, final Metadata metadata) {
+          String daprApiToken = Properties.API_TOKEN.get();
+          if (daprApiToken != null) {
+            metadata.put(Metadata.Key.of(Headers.DAPR_API_TOKEN, Metadata.ASCII_STRING_MARSHALLER), daprApiToken);
+          }
+          super.start(responseListener, metadata);
+        }
+      };
+    }
+  };
 }
+

sdk/src/main/java/io/dapr/client/Headers.java

@@ -16,20 +16,20 @@
 /**
  * Common headers for GRPC and HTTP communication.
  */
-class Headers {
+public final class Headers {
 
   /**
    * OpenCensus's metadata for GRPC.
    */
-  static final String GRPC_TRACE_BIN = "grpc-trace-bin";
+  public static final String GRPC_TRACE_BIN = "grpc-trace-bin";
 
   /**
    * Token for authentication from Application to Dapr runtime.
    */
-  static final String DAPR_API_TOKEN = "dapr-api-token";
+  public static final String DAPR_API_TOKEN = "dapr-api-token";
 
   /**
    * Header for Api Logging User-Agent.
    */
-  static final String DAPR_USER_AGENT = "User-Agent";  
+  public static final String DAPR_USER_AGENT = "User-Agent";
 }

sdk/src/main/java/io/dapr/utils/NetworkUtils.java

@@ -14,6 +14,7 @@
 package io.dapr.utils;
 
 import io.dapr.config.Properties;
+import io.grpc.ClientInterceptor;
 import io.grpc.ManagedChannel;
 import io.grpc.ManagedChannelBuilder;
 
@@ -57,9 +58,10 @@ public static void waitForSocket(String host, int port, int timeoutInMillisecond
 
   /**
    * Creates a GRPC managed channel.
+   * @param interceptors Optional interceptors to add to the channel.
    * @return GRPC managed channel to communicate with the sidecar.
    */
-  public static ManagedChannel buildGrpcManagedChannel() {
+  public static ManagedChannel buildGrpcManagedChannel(ClientInterceptor... interceptors) {
     String address = Properties.SIDECAR_IP.get();
     int port = Properties.GRPC_PORT.get();
     boolean insecure = true;
@@ -78,6 +80,9 @@ public static ManagedChannel buildGrpcManagedChannel() {
     if (insecure) {
       builder = builder.usePlaintext();
     }
+    if (interceptors != null && interceptors.length > 0) {
+      builder = builder.intercept(interceptors);
+    }
     return builder.build();
   }