From 02de64de5e1d28829ca535f0f1e404796abebacc Mon Sep 17 00:00:00 2001
From: philippe <t4rk@outlook.com>
Date: Wed, 26 Jun 2024 15:43:22 -0400
Subject: [PATCH 1/6] Add callback on_error handler
---
.pylintrc | 2 +-
dash/_callback.py | 25 +++++++--
dash/dash.py | 9 +++-
dash/long_callback/managers/__init__.py | 2 +-
dash/long_callback/managers/celery_manager.py | 37 +++++++++-----
.../managers/diskcache_manager.py | 34 ++++++++-----
.../callbacks/test_callback_error.py | 43 ++++++++++++++++
.../long_callback/app_bg_on_error.py | 51 +++++++++++++++++++
.../test_basic_long_callback018.py | 13 +++++
tests/integration/long_callback/utils.py | 9 ++--
10 files changed, 188 insertions(+), 37 deletions(-)
create mode 100644 tests/integration/callbacks/test_callback_error.py
create mode 100644 tests/integration/long_callback/app_bg_on_error.py
create mode 100644 tests/integration/long_callback/test_basic_long_callback018.py
diff --git a/.pylintrc b/.pylintrc
index 554f953b8e..6f86387a2b 100644
--- a/.pylintrc
+++ b/.pylintrc
@@ -414,7 +414,7 @@ max-bool-expr=5
max-branches=15
# Maximum number of locals for function / method body
-max-locals=20
+max-locals=25
# Maximum number of parents for a class (see R0901).
max-parents=7
diff --git a/dash/_callback.py b/dash/_callback.py
index 8ebc274213..a56461b708 100644
--- a/dash/_callback.py
+++ b/dash/_callback.py
@@ -1,6 +1,7 @@
import collections
import hashlib
from functools import wraps
+from typing import Callable, Optional, Any
import flask
@@ -67,6 +68,7 @@ def callback(
cancel=None,
manager=None,
cache_args_to_ignore=None,
+ on_error: Optional[Callable[[Exception], Any]] = None,
**_kwargs,
):
"""
@@ -137,6 +139,10 @@ def callback(
this should be a list of argument indices as integers.
:param interval:
Time to wait between the long callback update requests.
+ :param on_error:
+ Function to call when the callback raises an exception. Receives the
+ exception object as first argument. The callback_context can be used
+ to access the original callback inputs, states and output.
"""
long_spec = None
@@ -186,6 +192,7 @@ def callback(
long=long_spec,
manager=manager,
running=running,
+ on_error=on_error,
)
@@ -272,8 +279,8 @@ def insert_callback(
return callback_id
-# pylint: disable=R0912, R0915
-def register_callback( # pylint: disable=R0914
+# pylint: disable=too-many-branches,too-many-statements
+def register_callback(
callback_list, callback_map, config_prevent_initial_callbacks, *_args, **_kwargs
):
(
@@ -297,6 +304,7 @@ def register_callback( # pylint: disable=R0914
long = _kwargs.get("long")
manager = _kwargs.get("manager")
running = _kwargs.get("running")
+ on_error = _kwargs.get("on_error")
if running is not None:
if not isinstance(running[0], (list, tuple)):
running = [running]
@@ -342,6 +350,8 @@ def add_context(*args, **kwargs):
"callback_context", AttributeDict({"updated_props": {}})
)
callback_manager = long and long.get("manager", app_callback_manager)
+ app_on_error = kwargs.pop("app_on_error", None)
+
if has_output:
_validate.validate_output_spec(insert_output, output_spec, Output)
@@ -403,6 +413,7 @@ def add_context(*args, **kwargs):
triggered_inputs=callback_ctx.triggered_inputs,
ignore_register_page=True,
),
+ on_error=on_error or app_on_error,
)
data = {
@@ -462,7 +473,15 @@ def add_context(*args, **kwargs):
if output_value is callback_manager.UNDEFINED:
return to_json(response)
else:
- output_value = _invoke_callback(func, *func_args, **func_kwargs)
+ try:
+ output_value = _invoke_callback(func, *func_args, **func_kwargs)
+ except Exception as err: # pylint: disable=broad-exception-caught
+ if on_error:
+ output_value = on_error(err)
+ elif app_on_error:
+ output_value = app_on_error(err)
+ else:
+ raise err
if NoUpdate.is_no_update(output_value):
raise PreventUpdate
diff --git a/dash/dash.py b/dash/dash.py
index b17ef80c96..849581092c 100644
--- a/dash/dash.py
+++ b/dash/dash.py
@@ -16,7 +16,7 @@
import base64
import traceback
from urllib.parse import urlparse
-from typing import Dict, Optional, Union
+from typing import Any, Callable, Dict, Optional, Union
import flask
@@ -369,6 +369,10 @@ class Dash:
:param description: Sets a default description for meta tags on Dash pages (use_pages=True).
+ :param on_error: Global callback error handler to call when
+ an exception is raised. Receives the exception object as first argument.
+ The callback_context can be used to access the original callback inputs,
+ states and output.
"""
_plotlyjs_url: str
@@ -409,6 +413,7 @@ def __init__( # pylint: disable=too-many-statements
hooks: Union[RendererHooks, None] = None,
routing_callback_inputs: Optional[Dict[str, Union[Input, State]]] = None,
description=None,
+ on_error: Optional[Callable[[Exception], Any]] = None,
**obsolete,
):
_validate.check_obsolete(obsolete)
@@ -520,6 +525,7 @@ def __init__( # pylint: disable=too-many-statements
self._layout = None
self._layout_is_function = False
self.validation_layout = None
+ self._on_error = on_error
self._extra_components = []
self._setup_dev_tools()
@@ -1377,6 +1383,7 @@ def dispatch(self):
outputs_list=outputs_list,
long_callback_manager=self._background_manager,
callback_context=g,
+ app_on_error=self._on_error,
)
)
)
diff --git a/dash/long_callback/managers/__init__.py b/dash/long_callback/managers/__init__.py
index 6167828c60..e6f75fbb51 100644
--- a/dash/long_callback/managers/__init__.py
+++ b/dash/long_callback/managers/__init__.py
@@ -39,7 +39,7 @@ def job_running(self, job):
def make_job_fn(self, fn, progress, key=None):
raise NotImplementedError
- def call_job_fn(self, key, job_fn, args, context):
+ def call_job_fn(self, key, job_fn, args, context, on_error=None):
raise NotImplementedError
def get_progress(self, key):
diff --git a/dash/long_callback/managers/celery_manager.py b/dash/long_callback/managers/celery_manager.py
index 01fadf4f8d..d1e4a44bd1 100644
--- a/dash/long_callback/managers/celery_manager.py
+++ b/dash/long_callback/managers/celery_manager.py
@@ -89,7 +89,7 @@ def get_task(self, job):
def clear_cache_entry(self, key):
self.handle.backend.delete(key)
- def call_job_fn(self, key, job_fn, args, context):
+ def call_job_fn(self, key, job_fn, args, context, on_error=None):
task = job_fn.delay(key, self._make_progress_key(key), args, context)
return task.task_id
@@ -139,7 +139,9 @@ def _make_job_fn(fn, celery_app, progress, key):
cache = celery_app.backend
@celery_app.task(name=f"long_callback_{key}")
- def job_fn(result_key, progress_key, user_callback_args, context=None):
+ def job_fn(
+ result_key, progress_key, user_callback_args, context=None, on_error=None
+ ):
def _set_progress(progress_value):
if not isinstance(progress_value, (list, tuple)):
progress_value = [progress_value]
@@ -161,6 +163,7 @@ def run():
c.ignore_register_page = False
c.updated_props = ProxySetProps(_set_props)
context_value.set(c)
+ errored = False
try:
if isinstance(user_callback_args, dict):
user_callback_output = fn(*maybe_progress, **user_callback_args)
@@ -170,6 +173,7 @@ def run():
user_callback_output = fn(*maybe_progress, user_callback_args)
except PreventUpdate:
# Put NoUpdate dict directly to avoid circular imports.
+ errored = True
cache.set(
result_key,
json.dumps(
@@ -177,18 +181,23 @@ def run():
),
)
except Exception as err: # pylint: disable=broad-except
- cache.set(
- result_key,
- json.dumps(
- {
- "long_callback_error": {
- "msg": str(err),
- "tb": traceback.format_exc(),
- }
- },
- ),
- )
- else:
+ if on_error:
+ user_callback_output = on_error(err)
+ else:
+ errored = True
+ cache.set(
+ result_key,
+ json.dumps(
+ {
+ "long_callback_error": {
+ "msg": str(err),
+ "tb": traceback.format_exc(),
+ }
+ },
+ ),
+ )
+
+ if not errored:
cache.set(
result_key, json.dumps(user_callback_output, cls=PlotlyJSONEncoder)
)
diff --git a/dash/long_callback/managers/diskcache_manager.py b/dash/long_callback/managers/diskcache_manager.py
index a106700f82..0afb52bee0 100644
--- a/dash/long_callback/managers/diskcache_manager.py
+++ b/dash/long_callback/managers/diskcache_manager.py
@@ -115,13 +115,14 @@ def clear_cache_entry(self, key):
self.handle.delete(key)
# noinspection PyUnresolvedReferences
- def call_job_fn(self, key, job_fn, args, context):
+ def call_job_fn(self, key, job_fn, args, context, on_error=None):
# pylint: disable-next=import-outside-toplevel,no-name-in-module,import-error
from multiprocess import Process
# pylint: disable-next=not-callable
proc = Process(
- target=job_fn, args=(key, self._make_progress_key(key), args, context)
+ target=job_fn,
+ args=(key, self._make_progress_key(key), args, context, on_error),
)
proc.start()
return proc.pid
@@ -168,7 +169,7 @@ def get_updated_props(self, key):
def _make_job_fn(fn, cache, progress):
- def job_fn(result_key, progress_key, user_callback_args, context):
+ def job_fn(result_key, progress_key, user_callback_args, context, on_error):
def _set_progress(progress_value):
if not isinstance(progress_value, (list, tuple)):
progress_value = [progress_value]
@@ -187,6 +188,7 @@ def run():
c.ignore_register_page = False
c.updated_props = ProxySetProps(_set_props)
context_value.set(c)
+ errored = False
try:
if isinstance(user_callback_args, dict):
user_callback_output = fn(*maybe_progress, **user_callback_args)
@@ -195,18 +197,24 @@ def run():
else:
user_callback_output = fn(*maybe_progress, user_callback_args)
except PreventUpdate:
+ errored = True
cache.set(result_key, {"_dash_no_update": "_dash_no_update"})
except Exception as err: # pylint: disable=broad-except
- cache.set(
- result_key,
- {
- "long_callback_error": {
- "msg": str(err),
- "tb": traceback.format_exc(),
- }
- },
- )
- else:
+ if on_error:
+ user_callback_output = on_error(err)
+ else:
+ errored = True
+ cache.set(
+ result_key,
+ {
+ "long_callback_error": {
+ "msg": str(err),
+ "tb": traceback.format_exc(),
+ }
+ },
+ )
+
+ if not errored:
cache.set(result_key, user_callback_output)
ctx.run(run)
diff --git a/tests/integration/callbacks/test_callback_error.py b/tests/integration/callbacks/test_callback_error.py
new file mode 100644
index 0000000000..7021877d72
--- /dev/null
+++ b/tests/integration/callbacks/test_callback_error.py
@@ -0,0 +1,43 @@
+from dash import Dash, html, Input, Output
+
+
+def test_cber001_error_handler(dash_duo):
+ def global_callback_error_handler(err):
+ return f"global: {err}"
+
+ app = Dash(on_error=global_callback_error_handler)
+
+ app.layout = [
+ html.Button("start", id="start-local"),
+ html.Button("start-global", id="start-global"),
+ html.Div(id="output"),
+ html.Div(id="output-global"),
+ ]
+
+ def on_callback_error(err):
+ return f"callback: {err}"
+
+ @app.callback(
+ Output("output", "children"),
+ Input("start-local", "n_clicks"),
+ on_error=on_callback_error,
+ prevent_initial_call=True,
+ )
+ def on_start(_):
+ raise Exception("local error")
+
+ @app.callback(
+ Output("output-global", "children"),
+ Input("start-global", "n_clicks"),
+ prevent_initial_call=True,
+ )
+ def on_start_global(_):
+ raise Exception("global error")
+
+ dash_duo.start_server(app)
+ dash_duo.find_element("#start-local").click()
+
+ dash_duo.wait_for_text_to_equal("#output", "callback: local error")
+
+ dash_duo.find_element("#start-global").click()
+ dash_duo.wait_for_text_to_equal("#output-global", "global: global error")
diff --git a/tests/integration/long_callback/app_bg_on_error.py b/tests/integration/long_callback/app_bg_on_error.py
new file mode 100644
index 0000000000..7d69301b20
--- /dev/null
+++ b/tests/integration/long_callback/app_bg_on_error.py
@@ -0,0 +1,51 @@
+from dash import Dash, Input, Output, html
+from tests.integration.long_callback.utils import get_long_callback_manager
+
+long_callback_manager = get_long_callback_manager()
+handle = long_callback_manager.handle
+
+
+def global_error_handler(err):
+
+ return f"global: {err}"
+
+
+app = Dash(
+ __name__, long_callback_manager=long_callback_manager, on_error=global_error_handler
+)
+
+app.layout = [
+ html.Button("callback on_error", id="start-cb-onerror"),
+ html.Div(id="cb-output"),
+ html.Button("global on_error", id="start-global-onerror"),
+ html.Div(id="global-output"),
+]
+
+
+def callback_on_error(err):
+ return f"callback: {err}"
+
+
+@app.callback(
+ Output("cb-output", "children"),
+ Input("start-cb-onerror", "n_clicks"),
+ prevent_initial_call=True,
+ background=True,
+ on_error=callback_on_error,
+)
+def on_click(_):
+ raise Exception("callback error")
+
+
+@app.callback(
+ Output("global-output", "children"),
+ Input("start-global-onerror", "n_clicks"),
+ prevent_initial_call=True,
+ background=True,
+)
+def on_click_global(_):
+ raise Exception("global error")
+
+
+if __name__ == "__main__":
+ app.run(debug=True)
diff --git a/tests/integration/long_callback/test_basic_long_callback018.py b/tests/integration/long_callback/test_basic_long_callback018.py
new file mode 100644
index 0000000000..eba633e3a3
--- /dev/null
+++ b/tests/integration/long_callback/test_basic_long_callback018.py
@@ -0,0 +1,13 @@
+from tests.integration.long_callback.utils import setup_long_callback_app
+
+
+def test_lcbc017_long_callback_set_props(dash_duo, manager):
+ with setup_long_callback_app(manager, "app_bg_on_error") as app:
+ dash_duo.start_server(app)
+
+ dash_duo.find_element("#start-cb-onerror").click()
+
+ dash_duo.wait_for_text_to_equal("#cb-output", "callback: callback error")
+
+ dash_duo.find_element("#start-global-onerror").click()
+ dash_duo.wait_for_text_to_equal("#global-output", "global: global error")
diff --git a/tests/integration/long_callback/utils.py b/tests/integration/long_callback/utils.py
index 83b804848c..207673d3b3 100644
--- a/tests/integration/long_callback/utils.py
+++ b/tests/integration/long_callback/utils.py
@@ -18,8 +18,8 @@ def __init__(self, cache=None, cache_by=None, expire=None):
super().__init__(cache=cache, cache_by=cache_by, expire=expire)
self.running_jobs = []
- def call_job_fn(self, key, job_fn, args, context):
- pid = super().call_job_fn(key, job_fn, args, context)
+ def call_job_fn(self, key, job_fn, args, context, on_error=None):
+ pid = super().call_job_fn(key, job_fn, args, context, on_error=on_error)
self.running_jobs.append(pid)
return pid
@@ -135,8 +135,9 @@ def setup_long_callback_app(manager_name, app_name):
# Sleep for a couple of intervals
time.sleep(2.0)
- for job in manager.running_jobs:
- manager.terminate_job(job)
+ if hasattr(manager, "running_jobs"):
+ for job in manager.running_jobs:
+ manager.terminate_job(job)
shutil.rmtree(cache_directory, ignore_errors=True)
os.environ.pop("LONG_CALLBACK_MANAGER")
From 0a19ac592b12c313c2453113767982167470e85b Mon Sep 17 00:00:00 2001
From: philippe <t4rk@outlook.com>
Date: Wed, 26 Jun 2024 16:24:10 -0400
Subject: [PATCH 2/6] Fix celery on_error
---
dash/long_callback/managers/celery_manager.py | 2 +-
tests/integration/long_callback/test_basic_long_callback018.py | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/dash/long_callback/managers/celery_manager.py b/dash/long_callback/managers/celery_manager.py
index d1e4a44bd1..594a5a862c 100644
--- a/dash/long_callback/managers/celery_manager.py
+++ b/dash/long_callback/managers/celery_manager.py
@@ -90,7 +90,7 @@ def clear_cache_entry(self, key):
self.handle.backend.delete(key)
def call_job_fn(self, key, job_fn, args, context, on_error=None):
- task = job_fn.delay(key, self._make_progress_key(key), args, context)
+ task = job_fn.delay(key, self._make_progress_key(key), args, context, on_error)
return task.task_id
def get_progress(self, key):
diff --git a/tests/integration/long_callback/test_basic_long_callback018.py b/tests/integration/long_callback/test_basic_long_callback018.py
index eba633e3a3..b9a262dd9d 100644
--- a/tests/integration/long_callback/test_basic_long_callback018.py
+++ b/tests/integration/long_callback/test_basic_long_callback018.py
@@ -1,7 +1,7 @@
from tests.integration.long_callback.utils import setup_long_callback_app
-def test_lcbc017_long_callback_set_props(dash_duo, manager):
+def test_lcbc018_background_callback_on_error(dash_duo, manager):
with setup_long_callback_app(manager, "app_bg_on_error") as app:
dash_duo.start_server(app)
From 40130bd33fe24efb63d9b39993e82ffa0f0d2ee0 Mon Sep 17 00:00:00 2001
From: philippe <t4rk@outlook.com>
Date: Tue, 2 Jul 2024 12:47:40 -0400
Subject: [PATCH 3/6] raise back PreventUpdate
---
dash/_callback.py | 2 ++
1 file changed, 2 insertions(+)
diff --git a/dash/_callback.py b/dash/_callback.py
index a56461b708..06144460fb 100644
--- a/dash/_callback.py
+++ b/dash/_callback.py
@@ -475,6 +475,8 @@ def add_context(*args, **kwargs):
else:
try:
output_value = _invoke_callback(func, *func_args, **func_kwargs)
+ except PreventUpdate as err:
+ raise err
except Exception as err: # pylint: disable=broad-exception-caught
if on_error:
output_value = on_error(err)
From 30d6f1113e2f1d83762e32bce6ed131a46e98daa Mon Sep 17 00:00:00 2001
From: philippe <t4rk@outlook.com>
Date: Wed, 3 Jul 2024 15:09:04 -0400
Subject: [PATCH 4/6] on error without returning outputs, fix celery on_error.
---
dash/_callback.py | 50 ++++++++++++-------
dash/long_callback/managers/__init__.py | 2 +-
dash/long_callback/managers/celery_manager.py | 35 ++++++-------
.../managers/diskcache_manager.py | 29 +++++------
.../callbacks/test_callback_error.py | 6 +--
.../long_callback/app_bg_on_error.py | 7 ++-
.../test_basic_long_callback018.py | 4 +-
tests/integration/long_callback/utils.py | 10 +++-
8 files changed, 76 insertions(+), 67 deletions(-)
diff --git a/dash/_callback.py b/dash/_callback.py
index 06144460fb..619c2887c3 100644
--- a/dash/_callback.py
+++ b/dash/_callback.py
@@ -233,7 +233,7 @@ def insert_callback(
long=None,
manager=None,
running=None,
- dynamic_creator=False,
+ dynamic_creator: Optional[bool] = False,
no_output=False,
):
if prevent_initial_call is None:
@@ -279,6 +279,14 @@ def insert_callback(
return callback_id
+def _set_side_update(ctx, response) -> bool:
+ side_update = dict(ctx.updated_props)
+ if len(side_update) > 0:
+ response["sideUpdate"] = side_update
+ return True
+ return False
+
+
# pylint: disable=too-many-branches,too-many-statements
def register_callback(
callback_list, callback_map, config_prevent_initial_callbacks, *_args, **_kwargs
@@ -350,7 +358,7 @@ def add_context(*args, **kwargs):
"callback_context", AttributeDict({"updated_props": {}})
)
callback_manager = long and long.get("manager", app_callback_manager)
- app_on_error = kwargs.pop("app_on_error", None)
+ error_handler = on_error or kwargs.pop("app_on_error", None)
if has_output:
_validate.validate_output_spec(insert_output, output_spec, Output)
@@ -361,7 +369,7 @@ def add_context(*args, **kwargs):
args, inputs_state_indices
)
- response = {"multi": True}
+ response: dict = {"multi": True}
has_update = False
if long is not None:
@@ -413,7 +421,6 @@ def add_context(*args, **kwargs):
triggered_inputs=callback_ctx.triggered_inputs,
ignore_register_page=True,
),
- on_error=on_error or app_on_error,
)
data = {
@@ -451,10 +458,19 @@ def add_context(*args, **kwargs):
isinstance(output_value, dict)
and "long_callback_error" in output_value
):
- error = output_value.get("long_callback_error")
- raise LongCallbackError(
+ error = output_value.get("long_callback_error", {})
+ exc = LongCallbackError(
f"An error occurred inside a long callback: {error['msg']}\n{error['tb']}"
)
+ if error_handler:
+ error_handler(exc)
+ output_value = NoUpdate()
+ # set_props from the error handler uses the original ctx
+ # instead of manager.get_updated_props since it runs in the
+ # request process.
+ has_update = _set_side_update(callback_ctx, response)
+ else:
+ raise exc
if job_running and output_value is not callback_manager.UNDEFINED:
# cached results.
@@ -478,16 +494,15 @@ def add_context(*args, **kwargs):
except PreventUpdate as err:
raise err
except Exception as err: # pylint: disable=broad-exception-caught
- if on_error:
- output_value = on_error(err)
- elif app_on_error:
- output_value = app_on_error(err)
+ if error_handler:
+ error_handler(err)
+ if not multi:
+ output_value = NoUpdate()
+ else:
+ output_value = [NoUpdate for _ in output_spec]
else:
raise err
- if NoUpdate.is_no_update(output_value):
- raise PreventUpdate
-
component_ids = collections.defaultdict(dict)
if has_output:
@@ -508,12 +523,12 @@ def add_context(*args, **kwargs):
)
for val, spec in zip(flat_output_values, output_spec):
- if isinstance(val, NoUpdate):
+ if NoUpdate.is_no_update(val):
continue
for vali, speci in (
zip(val, spec) if isinstance(spec, list) else [[val, spec]]
):
- if not isinstance(vali, NoUpdate):
+ if not NoUpdate.is_no_update(vali):
has_update = True
id_str = stringify_id(speci["id"])
prop = clean_property_name(speci["property"])
@@ -527,10 +542,7 @@ def add_context(*args, **kwargs):
flat_output_values = []
if not long:
- side_update = dict(callback_ctx.updated_props)
- if len(side_update) > 0:
- has_update = True
- response["sideUpdate"] = side_update
+ has_update = _set_side_update(callback_ctx, response) or has_update
if not has_update:
raise PreventUpdate
diff --git a/dash/long_callback/managers/__init__.py b/dash/long_callback/managers/__init__.py
index e6f75fbb51..6167828c60 100644
--- a/dash/long_callback/managers/__init__.py
+++ b/dash/long_callback/managers/__init__.py
@@ -39,7 +39,7 @@ def job_running(self, job):
def make_job_fn(self, fn, progress, key=None):
raise NotImplementedError
- def call_job_fn(self, key, job_fn, args, context, on_error=None):
+ def call_job_fn(self, key, job_fn, args, context):
raise NotImplementedError
def get_progress(self, key):
diff --git a/dash/long_callback/managers/celery_manager.py b/dash/long_callback/managers/celery_manager.py
index 594a5a862c..612cc245fb 100644
--- a/dash/long_callback/managers/celery_manager.py
+++ b/dash/long_callback/managers/celery_manager.py
@@ -89,8 +89,8 @@ def get_task(self, job):
def clear_cache_entry(self, key):
self.handle.backend.delete(key)
- def call_job_fn(self, key, job_fn, args, context, on_error=None):
- task = job_fn.delay(key, self._make_progress_key(key), args, context, on_error)
+ def call_job_fn(self, key, job_fn, args, context):
+ task = job_fn.delay(key, self._make_progress_key(key), args, context)
return task.task_id
def get_progress(self, key):
@@ -139,9 +139,7 @@ def _make_job_fn(fn, celery_app, progress, key):
cache = celery_app.backend
@celery_app.task(name=f"long_callback_{key}")
- def job_fn(
- result_key, progress_key, user_callback_args, context=None, on_error=None
- ):
+ def job_fn(result_key, progress_key, user_callback_args, context=None):
def _set_progress(progress_value):
if not isinstance(progress_value, (list, tuple)):
progress_value = [progress_value]
@@ -181,21 +179,18 @@ def run():
),
)
except Exception as err: # pylint: disable=broad-except
- if on_error:
- user_callback_output = on_error(err)
- else:
- errored = True
- cache.set(
- result_key,
- json.dumps(
- {
- "long_callback_error": {
- "msg": str(err),
- "tb": traceback.format_exc(),
- }
- },
- ),
- )
+ errored = True
+ cache.set(
+ result_key,
+ json.dumps(
+ {
+ "long_callback_error": {
+ "msg": str(err),
+ "tb": traceback.format_exc(),
+ }
+ },
+ ),
+ )
if not errored:
cache.set(
diff --git a/dash/long_callback/managers/diskcache_manager.py b/dash/long_callback/managers/diskcache_manager.py
index 0afb52bee0..e1a110f14f 100644
--- a/dash/long_callback/managers/diskcache_manager.py
+++ b/dash/long_callback/managers/diskcache_manager.py
@@ -115,14 +115,14 @@ def clear_cache_entry(self, key):
self.handle.delete(key)
# noinspection PyUnresolvedReferences
- def call_job_fn(self, key, job_fn, args, context, on_error=None):
+ def call_job_fn(self, key, job_fn, args, context):
# pylint: disable-next=import-outside-toplevel,no-name-in-module,import-error
from multiprocess import Process
# pylint: disable-next=not-callable
proc = Process(
target=job_fn,
- args=(key, self._make_progress_key(key), args, context, on_error),
+ args=(key, self._make_progress_key(key), args, context),
)
proc.start()
return proc.pid
@@ -169,7 +169,7 @@ def get_updated_props(self, key):
def _make_job_fn(fn, cache, progress):
- def job_fn(result_key, progress_key, user_callback_args, context, on_error):
+ def job_fn(result_key, progress_key, user_callback_args, context):
def _set_progress(progress_value):
if not isinstance(progress_value, (list, tuple)):
progress_value = [progress_value]
@@ -200,19 +200,16 @@ def run():
errored = True
cache.set(result_key, {"_dash_no_update": "_dash_no_update"})
except Exception as err: # pylint: disable=broad-except
- if on_error:
- user_callback_output = on_error(err)
- else:
- errored = True
- cache.set(
- result_key,
- {
- "long_callback_error": {
- "msg": str(err),
- "tb": traceback.format_exc(),
- }
- },
- )
+ errored = True
+ cache.set(
+ result_key,
+ {
+ "long_callback_error": {
+ "msg": str(err),
+ "tb": traceback.format_exc(),
+ }
+ },
+ )
if not errored:
cache.set(result_key, user_callback_output)
diff --git a/tests/integration/callbacks/test_callback_error.py b/tests/integration/callbacks/test_callback_error.py
index 7021877d72..c828e31e7a 100644
--- a/tests/integration/callbacks/test_callback_error.py
+++ b/tests/integration/callbacks/test_callback_error.py
@@ -1,9 +1,9 @@
-from dash import Dash, html, Input, Output
+from dash import Dash, html, Input, Output, set_props
def test_cber001_error_handler(dash_duo):
def global_callback_error_handler(err):
- return f"global: {err}"
+ set_props("output-global", {"children": f"global: {err}"})
app = Dash(on_error=global_callback_error_handler)
@@ -15,7 +15,7 @@ def global_callback_error_handler(err):
]
def on_callback_error(err):
- return f"callback: {err}"
+ set_props("output", {"children": f"callback: {err}"})
@app.callback(
Output("output", "children"),
diff --git a/tests/integration/long_callback/app_bg_on_error.py b/tests/integration/long_callback/app_bg_on_error.py
index 7d69301b20..3132b6d8a0 100644
--- a/tests/integration/long_callback/app_bg_on_error.py
+++ b/tests/integration/long_callback/app_bg_on_error.py
@@ -1,4 +1,4 @@
-from dash import Dash, Input, Output, html
+from dash import Dash, Input, Output, html, set_props
from tests.integration.long_callback.utils import get_long_callback_manager
long_callback_manager = get_long_callback_manager()
@@ -6,8 +6,7 @@
def global_error_handler(err):
-
- return f"global: {err}"
+ set_props("global-output", {"children": f"global: {err}"})
app = Dash(
@@ -23,7 +22,7 @@ def global_error_handler(err):
def callback_on_error(err):
- return f"callback: {err}"
+ set_props("cb-output", {"children": f"callback: {err}"})
@app.callback(
diff --git a/tests/integration/long_callback/test_basic_long_callback018.py b/tests/integration/long_callback/test_basic_long_callback018.py
index b9a262dd9d..7dd0ca36d7 100644
--- a/tests/integration/long_callback/test_basic_long_callback018.py
+++ b/tests/integration/long_callback/test_basic_long_callback018.py
@@ -7,7 +7,7 @@ def test_lcbc018_background_callback_on_error(dash_duo, manager):
dash_duo.find_element("#start-cb-onerror").click()
- dash_duo.wait_for_text_to_equal("#cb-output", "callback: callback error")
+ dash_duo.wait_for_contains_text("#cb-output", "callback error")
dash_duo.find_element("#start-global-onerror").click()
- dash_duo.wait_for_text_to_equal("#global-output", "global: global error")
+ dash_duo.wait_for_contains_text("#global-output", "global error")
diff --git a/tests/integration/long_callback/utils.py b/tests/integration/long_callback/utils.py
index 207673d3b3..8c5c9e2a4f 100644
--- a/tests/integration/long_callback/utils.py
+++ b/tests/integration/long_callback/utils.py
@@ -18,8 +18,14 @@ def __init__(self, cache=None, cache_by=None, expire=None):
super().__init__(cache=cache, cache_by=cache_by, expire=expire)
self.running_jobs = []
- def call_job_fn(self, key, job_fn, args, context, on_error=None):
- pid = super().call_job_fn(key, job_fn, args, context, on_error=on_error)
+ def call_job_fn(
+ self,
+ key,
+ job_fn,
+ args,
+ context,
+ ):
+ pid = super().call_job_fn(key, job_fn, args, context)
self.running_jobs.append(pid)
return pid
From 3f003253c4c81a51aaa2bc0af7e4136e9ef13ca5 Mon Sep 17 00:00:00 2001
From: philippe <t4rk@outlook.com>
Date: Wed, 10 Jul 2024 14:20:34 -0400
Subject: [PATCH 5/6] Take the output value from the error handler only if not
None.
---
dash/_callback.py | 24 ++++++++++++++++--------
1 file changed, 16 insertions(+), 8 deletions(-)
diff --git a/dash/_callback.py b/dash/_callback.py
index 619c2887c3..0c7476fda1 100644
--- a/dash/_callback.py
+++ b/dash/_callback.py
@@ -463,12 +463,17 @@ def add_context(*args, **kwargs):
f"An error occurred inside a long callback: {error['msg']}\n{error['tb']}"
)
if error_handler:
- error_handler(exc)
- output_value = NoUpdate()
+ output_value = error_handler(exc)
+
+ if output_value is None:
+ output_value = NoUpdate()
# set_props from the error handler uses the original ctx
# instead of manager.get_updated_props since it runs in the
# request process.
- has_update = _set_side_update(callback_ctx, response)
+ has_update = (
+ _set_side_update(callback_ctx, response)
+ or output_value is not None
+ )
else:
raise exc
@@ -495,11 +500,14 @@ def add_context(*args, **kwargs):
raise err
except Exception as err: # pylint: disable=broad-exception-caught
if error_handler:
- error_handler(err)
- if not multi:
- output_value = NoUpdate()
- else:
- output_value = [NoUpdate for _ in output_spec]
+ output_value = error_handler(err)
+
+ # If the error returns nothing, automatically puts NoUpdate for response.
+ if output_value is None:
+ if not multi:
+ output_value = NoUpdate()
+ else:
+ output_value = [NoUpdate for _ in output_spec]
else:
raise err
From db28caf96342395bd537bcda59ec767188b87e57 Mon Sep 17 00:00:00 2001
From: philippe <t4rk@outlook.com>
Date: Thu, 11 Jul 2024 09:55:31 -0400
Subject: [PATCH 6/6] Test output is handled in error handler.
---
tests/integration/callbacks/test_callback_error.py | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/tests/integration/callbacks/test_callback_error.py b/tests/integration/callbacks/test_callback_error.py
index c828e31e7a..0a76ed741d 100644
--- a/tests/integration/callbacks/test_callback_error.py
+++ b/tests/integration/callbacks/test_callback_error.py
@@ -12,10 +12,12 @@ def global_callback_error_handler(err):
html.Button("start-global", id="start-global"),
html.Div(id="output"),
html.Div(id="output-global"),
+ html.Div(id="error-message"),
]
def on_callback_error(err):
- set_props("output", {"children": f"callback: {err}"})
+ set_props("error-message", {"children": f"message: {err}"})
+ return f"callback: {err}"
@app.callback(
Output("output", "children"),
@@ -38,6 +40,7 @@ def on_start_global(_):
dash_duo.find_element("#start-local").click()
dash_duo.wait_for_text_to_equal("#output", "callback: local error")
+ dash_duo.wait_for_text_to_equal("#error-message", "message: local error")
dash_duo.find_element("#start-global").click()
dash_duo.wait_for_text_to_equal("#output-global", "global: global error")