FT-800 Added better message logging for unhandled exceptions

webapp/src/main/java/org/apache/atlas/web/errors/ExceptionMapperUtil.java

@@ -19,15 +19,88 @@
 
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
+import java.util.ArrayList;
+import java.util.List;
 
 public class ExceptionMapperUtil {
     protected static final Logger LOGGER = LoggerFactory.getLogger(ExceptionMapperUtil.class);
 
     @SuppressWarnings("UnusedParameters")
     protected static String formatErrorMessage(long id, Exception exception) {
-        return String.format("There was an error processing your request. It has been logged (ID %016x).", id);
+        if (exception == null) {
+            // If the exception is null, return a minimal error message
+            return "{\n"
+                    + String.format("  \"errorId\": \"%016x\",\n", id)
+                    + "  \"message\": \"No exception provided\",\n"
+                    + "  \"causes\": []\n"
+                    + "}";
+        }
+
+        StringBuilder response = new StringBuilder();
+
+        // Add error ID and general error message
+        response.append("{\n")
+                .append(String.format("  \"errorId\": \"%016x\",\n", id))
+                .append("  \"message\": \"There was an error processing your request.\",\n")
+                .append("  \"causes\": [\n");
+
+        // Traverse through the chain of causes, avoiding cycles
+        List<String> causes = new ArrayList<>();
+        List<Throwable> visited = new ArrayList<>();
+        Throwable currentException = exception;
+        while (currentException != null) {
+            if (visited.contains(currentException)) {
+                causes.add("    {\n      \"errorType\": \"CircularReferenceDetected\",\n      \"errorMessage\": \"A circular reference was detected in the exception chain.\",\n      \"location\": \"Unavailable\"\n    }");
+                break;
+            }
+            visited.add(currentException);
+            causes.add(formatCause(currentException));
+            currentException = currentException.getCause();
+        }
+
+        // Add all formatted causes to the response
+        for (int i = 0; i < causes.size(); i++) {
+            response.append(causes.get(i));
+            if (i < causes.size() - 1) {
+                response.append(",\n");
+            }
+        }
+
+        // Close the JSON structure
+        response.append("\n  ]\n")
+                .append("}");
+
+        return response.toString();
     }
 
+    // Helper method to format a single exception cause
+    private static String formatCause(Throwable exception) {
+        StringBuilder cause = new StringBuilder();
+
+        // Extract location details from the first stack trace element
+        StackTraceElement[] stackTrace = exception.getStackTrace();
+        String location = "Unavailable";
+        if (stackTrace != null && stackTrace.length > 0) {
+            StackTraceElement element = stackTrace[0];
+            location = String.format("%s.%s (%s:%d)",
+                    element.getClassName(),
+                    element.getMethodName(),
+                    element.getFileName(),
+                    element.getLineNumber());
+        }
+
+        // Build JSON object for this cause
+        cause.append("    {\n")
+                .append("      \"errorType\": \"").append(exception.getClass().getName()).append("\",\n")
+                .append("      \"errorMessage\": \"").append(exception.getMessage() != null ? exception.getMessage() : "No additional information provided").append("\",\n")
+                .append("      \"location\": \"").append(location).append("\"\n")
+                .append("    }");
+
+        return cause.toString();
+    }
+
+
+
     protected static void logException(long id, Exception exception) {
         LOGGER.error(formatLogMessage(id, exception), exception);
     }