Improve logging for unexpected connection failures in DurableTaskGrpcWorker (#216)

Author: YunchuWang

CHANGELOG.md

@@ -1,4 +1,5 @@
 ## placeholder
+* Improve logging for unexpected connection failures in DurableTaskGrpcWorker ([#216](https://github.com/microsoft/durabletask-java/pull/216/files))
 * Add User-Agent Header to gRPC Metadata ([#213](https://github.com/microsoft/durabletask-java/pull/213))
 ## v1.5.0-preview.1
 * Update protobuf definitions to include new properties in OrchestratorRequest and update source commit hash ([#214](https://github.com/microsoft/durabletask-java/pull/214))

client/src/main/java/com/microsoft/durabletask/DurableTaskGrpcWorker.java

@@ -191,7 +191,7 @@ else if (requestType == RequestCase.HEALTHPING)
                 } else if (e.getStatus().getCode() == Status.Code.CANCELLED) {
                     logger.log(Level.INFO, "Durable Task worker has disconnected from {0}.", this.getSidecarAddress()); 
                 } else {
-                    logger.log(Level.WARNING, "Unexpected failure connecting to {0}.", this.getSidecarAddress());
+                    logger.log(Level.WARNING, String.format("Unexpected failure connecting to %s", this.getSidecarAddress()), e);
                 }
 
                 // Retry after 5 seconds