Improve resource render errors by including more detailed error messages.

Author: thet

CHANGES.rst

@@ -4,6 +4,10 @@ Changelog
 1.3 (unreleased)
 ----------------
 
+- Improve the error messages for the GracefulResourceRenderer to give an admin
+  better hints on what was going wrong.
+  [thet]
+
 - Do not wrap resource ``__repr__`` output in ``<>`` to render tracebacks
   properly in browser.
   [lenadax]
@@ -68,7 +72,7 @@ Changelog
   Modernize setup.[py|cfg].
   [jensens]
 
-- Added ``GracefulResourceRenderer``. 
+- Added ``GracefulResourceRenderer``.
   Fixes #1.
   [jensens]
 

webresource/_api.py

@@ -738,10 +738,19 @@ class GracefulResourceRenderer(ResourceRenderer):
     def render(self):
         lines = []
         for resource in self.resolver.resolve():
+            error_message = None
             try:
                 lines.append(resource.render(self.base_url))
-            except (ResourceError, FileNotFoundError):
-                msg = u'Failure to render resource "{}"'.format(resource.name)
-                lines.append(u'<!-- {} - details in logs -->'.format(msg))
-                logger.exception(msg)
+            except FileNotFoundError:
+                error_message = u'File not found for resource "{}"'.format(
+                    resource.name
+                )
+            except ResourceError as e:
+                error_message = str(e)
+            finally:
+                if error_message:
+                    lines.append(u'<!-- {} - details in logs -->'.format(
+                        error_message
+                    ))
+                    logger.exception(error_message)
         return u'\n'.join(lines)