Fix gRPC channel leak in DurableClientContext

azurefunctions/src/main/java/com/microsoft/durabletask/azurefunctions/DurableClientContext.java

@@ -22,8 +22,13 @@
 
 /**
  * The binding value type for the {@literal @}DurableClientInput parameter.
+ * <p>
+ * This class implements {@link AutoCloseable} to ensure proper cleanup of underlying gRPC resources.
+ * When used with the Azure Functions Java worker, the worker should call {@link #close()} after the
+ * function invocation completes to release network resources and prevent channel leak warnings.
+ * </p>
  */
-public class DurableClientContext {
+public class DurableClientContext implements AutoCloseable {
     // These fields are populated via GSON deserialization by the Functions Java worker.
     private String rpcBaseUrl;
     private String taskHubName;
@@ -44,7 +49,12 @@ public String getTaskHubName() {
      *
      * @return the Durable Task client object associated with the current function invocation.
      */
-    public DurableTaskClient getClient() {
+    public synchronized DurableTaskClient getClient() {
+        // Return existing client if already initialized
+        if (this.client != null) {
+            return this.client;
+        }
+
         if (this.rpcBaseUrl == null || this.rpcBaseUrl.length() == 0) {
             throw new IllegalStateException("The client context wasn't populated with an RPC base URL!");
         }
@@ -78,12 +88,10 @@ public HttpResponseMessage waitForCompletionOrCreateCheckStatusResponse(
             HttpRequestMessage<?> request,
             String instanceId,
             Duration timeout) {
-        if (this.client == null) {
-            this.client = getClient();
-        }
+        DurableTaskClient client = getClient();
         OrchestrationMetadata orchestration;
         try {
-            orchestration = this.client.waitForInstanceCompletion(instanceId, timeout, true);
+            orchestration = client.waitForInstanceCompletion(instanceId, timeout, true);
             return request.createResponseBuilder(HttpStatus.ACCEPTED)
                     .header("Content-Type", "application/json")
                     .body(orchestration.getSerializedOutput())
@@ -148,4 +156,20 @@ private String getInstanceStatusURL(HttpRequestMessage<?> request, String instan
 
         return baseUrl + "/runtime/webhooks/durabletask/instances/" + encodedInstanceId;
     }
+
+    /**
+     * Closes the underlying durable task client and releases any associated network resources.
+     * <p>
+     * This method should be called when the function invocation is complete to prevent gRPC channel leaks.
+     * If no client has been created yet (i.e., {@link #getClient()} was never called), this method does nothing.
+     * This method is idempotent and can be called multiple times safely.
+     * </p>
+     */
+    @Override
+    public synchronized void close() {
+        if (this.client != null) {
+            this.client.close();
+            this.client = null;
+        }
+    }
 }

internal/durabletask-protobuf/PROTO_SOURCE_COMMIT_HASH

@@ -1 +1 @@
-fbe5bb20835678099fc51a44993ed9b045dee5a6
+026329c53fe6363985655857b9ca848ec7238bd2