add hide_errors argument in App to control error traceback display (#489)

Author: pplonski

mercury/apps/nb/nbrun.py

@@ -25,6 +25,7 @@ def __init__(
         is_presentation=False,
         reveal_theme="white",
         stop_on_error=False,
+        hide_errors=True,
         user_info=None,
     ):
         self.exporter = Exporter(show_code, show_prompt, is_presentation, reveal_theme)
@@ -38,10 +39,14 @@ def __init__(
             init_code += f"os.environ['MERCURY_USER_INFO']='{user_info}'"
         self.shell.run(init_code)
         self.stop_on_error = stop_on_error
+        self.hide_errors = hide_errors
 
     def set_stop_on_error(self, new_stop_on_error):
         self.stop_on_error = new_stop_on_error
 
+    def set_hide_errors(self, new_hide_errors):
+        self.hide_errors = new_hide_errors
+
     def set_show_code(self, new_show_code):
         self.exporter.set_show_code(new_show_code)
 
@@ -80,6 +85,9 @@ def run_cell(self, cell, counter=None):
                         return False
                     if self.stop_on_error and output.get("output_type", "") == "error":
                         return False
+                    if self.hide_errors and output.get("output_type", "") == "error":
+                        cell.outputs = []
+                        break
 
             except Exception as e:
                 pass

mercury/apps/nb/tests/test_nbrun.py

@@ -43,3 +43,16 @@ def test_stop_on_error(self):
         nbrun = NbRun(stop_on_error=True)
         nbrun.run_notebook(nb)
         self.assertTrue(len(nb.cells[2].outputs) == 0)
+
+
+    def test_hide_errors(self):
+        nb = test_notebook(code=["not-working"])
+        nb = dict2nb(nb)
+
+        nbrun = NbRun(hide_errors=False)
+        nbrun.run_notebook(nb)
+        self.assertTrue(len(nb.cells[0].outputs) > 0)
+
+        nbrun = NbRun(hide_errors=True)
+        nbrun.run_notebook(nb)
+        self.assertTrue(len(nb.cells[0].outputs) == 0)

mercury/apps/nbworker/nb.py

@@ -349,6 +349,7 @@ def init_notebook(self):
             is_presentation=self.is_presentation(),
             reveal_theme=self.reveal_theme(),
             stop_on_error=self.stop_on_error(),
+            hide_errors=self.hide_errors(),
             user_info=self.get_user_info(),
         )
 
@@ -387,6 +388,7 @@ def init_notebook(self):
             )
             self.nbrun.set_is_presentation(nb_params.get("output", "app") == "slides")
             self.nbrun.set_stop_on_error(nb_params.get("stop_on_error", False))
+            self.nbrun.set_hide_errors(nb_params.get("hide_errors", True))
 
             log.info(params)
             log.info(f"Exporter show_code {self.nbrun.exporter.show_code}")

mercury/apps/nbworker/rest.py

@@ -87,6 +87,7 @@ def update_notebook(self, new_params):
             "allow_download",
             "allow_share",
             "stop_on_error",
+            "hide_errors"
         ]:
             if new_params.get(property) is not None and nb_params.get(
                 property
@@ -161,6 +162,17 @@ def stop_on_error(self):
         except Exception:
             log.exception("Exception when check if stop_on_error")
         return False
+    
+    def hide_errors(self):
+        try:
+            hide_errors = str(
+                json.loads(self.notebook.params).get("hide_errors", "true")
+            ).lower()
+            log.info(f"Check if hide_errors ({hide_errors})")
+            return hide_errors == "true"
+        except Exception:
+            log.exception("Exception when check if hide_errors")
+        return False
 
     def worker_state(self):
         return self.state

mercury/apps/ws/utils.py

@@ -135,6 +135,7 @@ def parse_params(nb, params={}):
                         "allow_download",
                         "allow_share",
                         "stop_on_error",
+                        "hide_errors"
                     ]:
                         if view.get(property) is not None:
                             params[property] = view.get(property)
@@ -164,6 +165,8 @@ def parse_params(nb, params={}):
         params["allow_share"] = True
     if params.get("stop_on_error") is None:
         params["stop_on_error"] = False
+    if params.get("hide_errors") is None:
+        params["hide_errors"] = True
 
     if no_outputs:
         params["version"] = "2"

mercury/widgets/app.py

@@ -78,6 +78,11 @@ class App:
         The default is False, meaning the notebook will execute all cells even with 
         errors.
 
+    hide_errors : bool, default True
+        If True, the notebook will not display errors and exceptions from notebook
+        execution. Please set to False if you would like to see error messages and 
+        traceback in the notebook.
+
     Examples
     --------
     Constructing Mercury App with `title` and `description` arguments.
@@ -106,6 +111,7 @@ def __init__(
         allow_download=True,
         allow_share=True,
         stop_on_error=False,
+        hide_errors=True,
     ):
         self.code_uid = WidgetsManager.get_code_uid("App")
         self.title = title
@@ -122,6 +128,7 @@ def __init__(
         self.allow_download = allow_download
         self.allow_share = allow_share
         self.stop_on_error = stop_on_error
+        self.hide_errors = hide_errors
         display(self)
 
     def __repr__(self):
@@ -149,6 +156,7 @@ def _repr_mimebundle_(self, **kwargs):
             "allow_download": self.allow_download,
             "allow_share": self.allow_share,
             "stop_on_error": self.stop_on_error,
+            "hide_errors": self.hide_errors,
             "model_id": "mercury-app",
             "code_uid": self.code_uid,
         }