Timeout & Assync Fixes

- Fix: Parser Error that occurs when MOA ZS goes into service timeout.
- Fix: Improve exception handling on MOA ZS Async.
- Before: When MOA ZS processes delivery request but hits a timeout,
  MOA ZS would answer syncronously to the Sender app and forward
  the result assynchronously at a later point. If an exception were to
  occur after the timeout, MOA ZS would swallow this exception.
- Now: If an exception occurs, MOA ZS converts the exception into a
  response and hands it over to the sink hub for proper processing of
  the event.

2 files changed, 55 insertions, 5 deletions

diff --git a/src/main/java/at/gv/egiz/moazs/backend/SaveResponseToFileSink.java b/src/main/java/at/gv/egiz/moazs/backend/SaveResponseToFileSink.java
index c844511..d442add 100644
--- a/src/main/java/at/gv/egiz/moazs/backend/SaveResponseToFileSink.java
+++ b/src/main/java/at/gv/egiz/moazs/backend/SaveResponseToFileSink.java
@@ -86,7 +86,7 @@ public class SaveResponseToFileSink {
                 .exceptionally(ex -> logException(ex, responseID));
 
         var binaryResponsePath = generatePath(rootPath, responseID, "binary.xml");
-        var storeBinaryResponseToFileSystemFuture = supplyAsync(() -> repository.retrieveBinaryResponse(responseID).get(), taskExecutor)
+        var storeBinaryResponseToFileSystemFuture = supplyAsync(() -> repository.retrieveBinaryResponse(responseID).orElse(new byte[0]), taskExecutor)
                 .thenAccept(binaryResponseByteArray -> storeToFile(binaryResponsePath, binaryResponseByteArray))
                 .exceptionally(ex -> logException(ex, responseID));
 
diff --git a/src/main/java/at/gv/egiz/moazs/service/MzsService.java b/src/main/java/at/gv/egiz/moazs/service/MzsService.java
index 565e374..a2af4f1 100644
--- a/src/main/java/at/gv/egiz/moazs/service/MzsService.java
+++ b/src/main/java/at/gv/egiz/moazs/service/MzsService.java
@@ -46,6 +46,9 @@ import java.util.function.Consumer;
 
 import static at.gv.egiz.moazs.MoaZSException.moaZSException;
 import static at.gv.zustellung.app2mzs.xsd.PartialSuccessType.partialSuccessTypeBuilder;
+import static at.gv.zustellung.msg.xsd.DeliveryRequestStatusType.Error.errorBuilder;
+import static at.gv.zustellung.msg.xsd.DeliveryRequestStatusType.deliveryRequestStatusTypeBuilder;
+import static at.gv.zustellung.msg.xsd.ErrorInfoType.errorInfoTypeBuilder;
 import static java.lang.String.format;
 import static java.lang.Thread.currentThread;
 import static java.util.concurrent.CompletableFuture.supplyAsync;
@@ -149,15 +152,62 @@ public class MzsService implements App2MzsPortType {
         log.info(SERVICE_TIME_OUT_REACHED_MSG, appDeliveryID);
         var sinkParams = request.getConfig().getMsgResponseSinks();
 
-        requestProcessed.thenCompose(response -> hub.applySinks(response, sinkParams));
+        requestProcessed
+                .exceptionally(e -> logErrorAndConvert(e, request))
+                .thenCompose(response -> hub.applySinks(response, sinkParams));
 
-        return generatePartialSuccessResponse(appDeliveryID);
+        var deliverySystem = request.getConfig().getMSGClient().getURL();
+        return generatePartialSuccessResponse(appDeliveryID, deliverySystem);
     }
 
-    private DeliveryResponseType generatePartialSuccessResponse(String appDeliveryId) {
+    private RequestStatusResponse logErrorAndConvert(Throwable exception, DeliveryRequestType request) {
+
+        var appDeliveryID = request.getMetaData().getAppDeliveryID();
+        var errorMessage = format(MZS_SERVICE_ERROR_MSG, appDeliveryID);
+        log.error(errorMessage, exception);
+
+        var explanation = generateExplanation(exception);
+        var text = format("%s Reason: %s", errorMessage, explanation);
+
+        var errorInfo = errorInfoTypeBuilder()
+                .withCode("500")
+                .withText(text)
+                .build();
+
+        var deliverySystem = request.getConfig().getMSGClient().getURL();
+        var zsDeliveryID = "unknown";
+        var error = errorBuilder()
+                .withErrorInfo(errorInfo)
+                .withDeliverySystem(deliverySystem)
+                .withZSDeliveryID(zsDeliveryID)
+                .withAppDeliveryID(appDeliveryID)
+                .build();
+
+        var status = deliveryRequestStatusTypeBuilder()
+                .withError(error)
+                .build();
+
+        return new RequestStatusResponse(status);
+    }
+
+    private String generateExplanation(Throwable exception) {
+
+        StringBuilder s = new StringBuilder(exception.toString());
+        Throwable cause = exception.getCause();
+
+        while (cause != null && cause != cause.getCause()) {
+            s.append("; Reason: ").append(cause.toString());
+            cause = cause.getCause();
+        }
+
+        return s.toString();
+    }
+
+    private DeliveryResponseType generatePartialSuccessResponse(String appDeliveryID, String deliverySystem) {
 
         var partial = partialSuccessTypeBuilder()
-                .withAppDeliveryID(appDeliveryId)
+                .withAppDeliveryID(appDeliveryID)
+                .withDeliverySystem(deliverySystem)
                 .build();
 
         return DeliveryResponseType.deliveryResponseTypeBuilder()