Product fetcher: better errors

apps/cli/executables/pexable/productfetcher/productfetcher/exceptions.py

@@ -6,6 +6,7 @@ The distinction matters to the RetryingFileFetcher, which will re-attempt a fetc
 if it is interrupted by a RetryableFetchError.
 
 """
+import traceback
 from pathlib import Path
 
 
@@ -19,6 +20,7 @@ class FetchError(Exception):
 
     def terminate_fetch(self):
         print(self.message)
+        traceback.print_exception(type(self), self, self.__traceback__)
 
 
 class RetryableFetchError(FetchError):
@@ -32,7 +34,7 @@ class RetryableFetchError(FetchError):
     def terminate_fetch(self):
         print(f"A retryable problem occurred, but was not resolved after {self.retries} retries.")
         print("You may succeed by running the program again.")
-        print(self.message)
+        super().terminate_fetch()
 
 
 class FileValidationFault(FetchError):
@@ -74,9 +76,7 @@ class NgasServiceErrorException(FetchError):
         self.reason = reason
 
     def terminate_fetch(self):
-        print(
-            f"NGAS error: {self.message} ({self.url} returned {self.status_code} with reason {self.reason})"
-        )
+        print(f"NGAS error: {self.message} ({self.url} returned {self.status_code} with reason {self.reason})")
 
 
 class LocatorServiceException(FetchError):