Jupyter Kernel: added automatic error rendering

Now the ERP5 Jupyter kernel automatically renders errors that happens in the
user-side code. Errors are captured during the AST tree creation (to be able to
detect syntax errors) and at execution time. The current transaction is
automatically aborted on error detection, thus notebook lines are not added.

TODO: on error detection store somehow what line caused the error and
information about the error itself.

bt5/erp5_data_notebook/ExtensionTemplateItem/portal_components/extension.erp5.JupyterCompile.py

@@ -8,6 +8,9 @@ import sys
 import ast
 import types
 import inspect
+import traceback
+
+import transaction
 
 mime_type = 'text/plain'
 # IPython expects 2 status message - 'ok', 'error'
@@ -79,7 +82,13 @@ def Base_compileJupyterCode(self, jupyter_code, old_local_variable_dict):
   if jupyter_code:
   
     # Create ast parse tree
-    ast_node = ast.parse(jupyter_code)
+    try:
+      ast_node = ast.parse(jupyter_code)
+    except Exception as e:
+      # It's not necessary to abort the current transaction here 'cause the 
+      # user's code wasn't executed at all yet.
+      return getErrorMessageForException(self, e, local_variable_dict)
+      
     # Get the node list from the parsed tree
     nodelist = ast_node.body
 
@@ -116,13 +125,35 @@ def Base_compileJupyterCode(self, jupyter_code, old_local_variable_dict):
       for node in to_run_exec:
         mod = ast.Module([node])
         code = compile(mod, '<string>', "exec")
-        exec(code, g, g)
+        try:
+          exec(code, g, g)
+        except Exception as e:
+          # Abort the current transaction. As a consequence, the notebook lines
+          # are not added if an exception occurs.
+          #
+          # TODO: store which notebook line generated which exception.
+          #
+          transaction.abort()
+          # Clear the portal cache from previous transaction
+          self.getPortalObject().portal_caches.clearAllCache()
+          return getErrorMessageForException(self, e, local_variable_dict)
 
       # Execute the interactive nodes with 'single' mode
       for node in to_run_interactive:
         mod = ast.Interactive([node])
         code = compile(mod, '<string>', "single")
-        exec(code, g, g)
+        try:
+          exec(code, g, g)
+        except Exception as e:
+          # Abort the current transaction. As a consequence, the notebook lines
+          # are not added if an exception occurs.
+          #
+          # TODO: store which notebook line generated which exception.
+          #
+          transaction.abort()
+          # Clear the portal cache from previous transaction
+          self.getPortalObject().portal_caches.clearAllCache()
+          return getErrorMessageForException(self, e, local_variable_dict)
 
       # Letting the code fail in case of error while executing the python script/code
       # XXX: Need to be refactored so to acclimitize transactions failure as well as
@@ -168,6 +199,24 @@ def Base_compileJupyterCode(self, jupyter_code, old_local_variable_dict):
 
   return result
 
+def getErrorMessageForException(self, exception, local_variable_dict):
+  '''
+    getErrorMessageForException receives an Expcetion object and a context for
+    code execution (local_variable_dict) and will return a dict as Jupyter
+    requires for error rendering.
+  '''
+  etype, value, tb = sys.exc_info()
+  traceback_text = traceback.format_exc().split('\n')[:-1]
+  return {
+    'status': 'error',
+    'result_string': None,
+    'local_variable_dict': local_variable_dict,
+    'mime_type': 'text/plain',
+    'evalue': str(value),
+    'ename': exception.__class__.__name__,
+    'traceback': traceback_text
+  }
+
 def AddNewLocalVariableDict(self):
   """
   Function to add a new Local Variable for a Data Notebook
@@ -323,4 +372,4 @@ def getError(self, previous=1):
   evalue = unicode(error['value'])
   tb_list = [l+'\n' for l in error['tb_text'].split('\n')]
 
-  return None
+  return None
\ No newline at end of file

bt5/erp5_data_notebook/ExtensionTemplateItem/portal_components/extension.erp5.JupyterCompile.xml

@@ -46,12 +46,14 @@
             <key> <string>text_content_warning_message</string> </key>
             <value>
               <tuple>
-                <string>W: 55,  2: Using the global statement (global-statement)</string>
-                <string>W: 95,  8: Use of exec (exec-used)</string>
-                <string>W:119,  8: Use of exec (exec-used)</string>
-                <string>W:125,  8: Use of exec (exec-used)</string>
-                <string>W:220,  4: Using the global statement (global-statement)</string>
-                <string>W:320,  2: Using the global statement (global-statement)</string>
+                <string>W: 58,  2: Using the global statement (global-statement)</string>
+                <string>W:104,  8: Use of exec (exec-used)</string>
+                <string>W:129, 10: Use of exec (exec-used)</string>
+                <string>W:146, 10: Use of exec (exec-used)</string>
+                <string>W:208,  2: Unused variable \'etype\' (unused-variable)</string>
+                <string>W:208, 16: Unused variable \'tb\' (unused-variable)</string>
+                <string>W:269,  4: Using the global statement (global-statement)</string>
+                <string>W:369,  2: Using the global statement (global-statement)</string>
               </tuple>
             </value>
         </item>

bt5/erp5_data_notebook/SkinTemplateItem/portal_skins/erp5_data_notebook/Base_renderAsHtml.xml

+<?xml version="1.0"?>
+<ZopeData>
+  <record id="1" aka="AAAAAAAAAAE=">
+    <pickle>
+      <global name="ExternalMethod" module="Products.ExternalMethod.ExternalMethod"/>
+    </pickle>
+    <pickle>
+      <dictionary>
+        <item>
+            <key> <string>_function</string> </key>
+            <value> <string>renderAsHtml</string> </value>
+        </item>
+        <item>
+            <key> <string>_module</string> </key>
+            <value> <string>JupyterCompile</string> </value>
+        </item>
+        <item>
+            <key> <string>id</string> </key>
+            <value> <string>Base_renderAsHtml</string> </value>
+        </item>
+        <item>
+            <key> <string>title</string> </key>
+            <value> <string></string> </value>
+        </item>
+      </dictionary>
+    </pickle>
+  </record>
+</ZopeData>

bt5/erp5_data_notebook/TestTemplateItem/portal_components/test.erp5.testExecuteJupyter.py

@@ -32,7 +32,7 @@ from Products.ERP5Type.tests.utils import createZODBPythonScript, removeZODBPyth
 import time
 import json
 import base64
-import transaction
+
 
 class TestExecuteJupyter(ERP5TypeTestCase):
   
@@ -100,21 +100,25 @@ print an_undefined_variable
 portal = context.getPortalObject()
 portal.%s()
 """%script_id
-
+    
     # Make call to Base_runJupyter to run the jupyter code which is making
-    # a call to the newly created ZODB python_script and assert if the call raises
-    # NameError as we are sending an invalid python_code to it
-    self.assertRaises(
-                      NameError,
-                      portal.Base_runJupyter,
-                      jupyter_code=jupyter_code,
-                      old_local_variable_dict=portal.Base_addLocalVariableDict()
-                      )
-    # Abort the current transaction of test so that we can proceed to new one
-    transaction.abort()
-    # Clear the portal cache from previous transaction
-    self.portal.portal_caches.clearAllCache()
-    # Remove the ZODB python script created above
+    # a call to the newly created ZODB python_script and assert if the call 
+    # processes correctly the NameError as we are sending an invalid 
+    # python_code to it.
+    # 
+    result = portal.Base_runJupyter(
+      jupyter_code=jupyter_code, 
+      old_local_variable_dict=portal.Base_addLocalVariableDict()
+    )
+    
+    self.assertEquals(result['ename'], 'NameError')
+    self.assertEquals(result['result_string'], None)
+    
+    # There's no need to abort the current transaction. The error handling code
+    # should be responsible for this, so we check the script's title
+    script_title = script_container.JupyterCompile_errorResult.getTitle()
+    self.assertNotEqual(script_title, new_test_title)
+    
     removeZODBPythonScript(script_container, script_id)
 
     # Test that calling Base_runJupyter shouldn't change the context Title
@@ -248,13 +252,14 @@ portal.%s()
     reference = 'Test.Notebook.ExecuteJupyterErrorHandling %s' % time.time()
     title = 'Test NB Title %s' % time.time()
 
-    self.assertRaises(
-                      NameError, 
-                      portal.Base_executeJupyter,
-                      title=title,
-                      reference=reference,
-                      python_expression=python_expression
-                      )
+    result = json.loads(portal.Base_executeJupyter(
+      title=title, 
+      reference=reference, 
+      python_expression=python_expression
+    ))
+    
+    self.assertEquals(result['ename'], 'NameError')
+    self.assertEquals(result['code_result'], None)
 
   def testBaseExecuteJupyterSaveActiveResult(self):
     """
@@ -429,4 +434,4 @@ context.Base_displayImage(image_object=image)
       reference=reference,
       python_expression=jupyter_code2
       )
-    self.assertEquals(json.loads(result)['code_result'].rstrip(), 'sys')
+    self.assertEquals(json.loads(result)['code_result'].rstrip(), 'sys')
\ No newline at end of file