Better error display.

bonobo/config/services.py

@@ -2,6 +2,7 @@ import re
 import types
 
 from bonobo.config.options import Option
+from bonobo.errors import MissingServiceImplementationError
 
 _service_name_re = re.compile(r"^[^\d\W]\w*(:?\.[^\d\W]\w*)*$", re.UNICODE)
 
@@ -78,7 +79,7 @@ class Container(dict):
         if not name in self:
             if default:
                 return default
-            raise KeyError('Cannot resolve service {!r} using provided service collection.'.format(name))
+            raise MissingServiceImplementationError('Cannot resolve service {!r} using provided service collection.'.format(name))
         value = super().get(name)
         if isinstance(value, types.LambdaType):
             value = value(self)

bonobo/errors.py

@@ -55,4 +55,7 @@ class ProhibitedOperationError(RuntimeError):
 
 
 class ConfigurationError(Exception):
+    pass
+
+class MissingServiceImplementationError(KeyError):
     pass

bonobo/examples/nodes/_services.py

@@ -0,0 +1,5 @@
+from bonobo import get_examples_path, open_fs
+
+
+def get_services():
+    return {'fs': open_fs(get_examples_path())}

bonobo/execution/base.py

@@ -55,10 +55,9 @@ class LoopingExecutionContext(Wrapper):
             raise RuntimeError('Cannot start a node twice ({}).'.format(get_name(self)))
 
         self._started = True
-        self._stack = ContextCurrifier(self.wrapped, *self._get_initial_context())
 
-        with unrecoverable(self.handle_error):
-            self._stack.setup(self)
+        self._stack = ContextCurrifier(self.wrapped, *self._get_initial_context())
+        self._stack.setup(self)
 
         for enhancer in self._enhancers:
             with unrecoverable(self.handle_error):
@@ -82,7 +81,7 @@ class LoopingExecutionContext(Wrapper):
             return
 
         try:
-            with unrecoverable(self.handle_error):
+            if self._stack:
                 self._stack.teardown()
         finally:
             self._stopped = True

bonobo/strategies/executor.py

@@ -36,7 +36,7 @@ class ExecutorStrategy(Strategy):
                     plugin_context.loop()
                     plugin_context.stop()
                 except Exception as exc:
-                    print_error(exc, traceback.format_exc(), prefix='Error in plugin context', context=plugin_context)
+                    print_error(exc, traceback.format_exc(), context=plugin_context)
 
             futures.append(executor.submit(_runner))
 
@@ -46,9 +46,7 @@ class ExecutorStrategy(Strategy):
                 try:
                     node_context.start()
                 except Exception as exc:
-                    print_error(
-                        exc, traceback.format_exc(), prefix='Could not start node context', context=node_context
-                    )
+                    print_error(exc, traceback.format_exc(), context=node_context, method='start')
                     node_context.input.on_end()
                 else:
                     node_context.loop()
@@ -56,7 +54,7 @@ class ExecutorStrategy(Strategy):
                 try:
                     node_context.stop()
                 except Exception as exc:
-                    print_error(exc, traceback.format_exc(), prefix='Could not stop node context', context=node_context)
+                    print_error(exc, traceback.format_exc(), context=node_context, method='stop')
 
             futures.append(executor.submit(_runner))
 

bonobo/util/errors.py

@@ -1,5 +1,7 @@
 import sys
+from textwrap import indent
 
+from bonobo import settings
 from bonobo.structs.bags import ErrorBag
 
 
@@ -7,7 +9,14 @@ def is_error(bag):
     return isinstance(bag, ErrorBag)
 
 
-def print_error(exc, trace, context=None, prefix=''):
+def _get_error_message(exc):
+    if hasattr(exc, '__str__'):
+        message = str(exc)
+        return message[0].upper() + message[1:]
+    return '\n'.join(exc.args),
+
+
+def print_error(exc, trace, context=None, method=None):
     """
     Error handler. Whatever happens in a plugin or component, if it looks like an exception, taste like an exception
     or somehow make me think it is an exception, I'll handle it.
@@ -18,14 +27,21 @@ def print_error(exc, trace, context=None, prefix=''):
     """
 
     from colorama import Fore, Style
+
+    prefix = '{}{} | {}'.format(Fore.RED, Style.BRIGHT, Style.RESET_ALL)
+
     print(
         Style.BRIGHT,
         Fore.RED,
-        '\U0001F4A3 {}{}{}'.format(
-            (prefix + ': ') if prefix else '', type(exc).__name__, ' in {!r}'.format(context) if context else ''
-        ),
+        type(exc).__name__,
+        ' (in {}{})'.format(type(context).__name__, '.{}()'.format(method) if method else '') if context else '',
+        Style.RESET_ALL,
+        '\n',
+        indent(_get_error_message(exc), prefix+Style.BRIGHT),
         Style.RESET_ALL,
         sep='',
         file=sys.stderr,
     )
-    print(trace)
+    print(prefix, file=sys.stderr)
+    print(indent(trace, prefix, predicate=lambda line: True), file=sys.stderr)
+