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[WIP] Delay callback validation #644

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141 changes: 81 additions & 60 deletions dash/dash.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -12,7 +12,6 @@
import warnings
import re
import logging
import pprint

from functools import wraps

Expand Down Expand Up @@ -165,6 +164,9 @@ def __init__(
# list of dependencies
self.callback_map = {}

# for delayed callback validation
self._callback_list = []

self._index_string = ''
self.index_string = index_string
self._meta_tags = meta_tags or []
Expand Down Expand Up @@ -641,6 +643,73 @@ def react(self, *args, **kwargs):
'Use `callback` instead. `callback` has a new syntax too, '
'so make sure to call `help(app.callback)` to learn more.')

def _validate_callbacks(self):
# Maps all registered Output components (including individual Outputs
# within multi-output callbacks) onto their associated callback
# function names)
output_map = collections.defaultdict(list)

for output, inputs, state, func_name in self._callback_list:
self._validate_callback(output, inputs, state)

outputs = output if isinstance(output, (list, tuple)) else [output]
for out in outputs:
output_map[out].append(func_name)

# Each Output should only have one callback function associated with it
duplicates = [(output, funcs) for output, funcs in output_map.items()
if len(funcs) > 1]
if not duplicates:
return

msg1 = ""
msg2 = ""
diff_callback = []
same_callback = []

def get_error_lines(dupes):
err_str = '{} in callback function{}: {}'
lines = []
for output, funcs in dupes:
func_names = ', '.join("'{}'".format(f) for f in funcs)
plural = 's' if len(funcs) > 1 else ''
lines.append(err_str.format(repr(output), plural, func_names))
return '\n'.join(lines)

for output, funcs in duplicates:
if len(set(funcs)) < len(funcs):
# Single Output used multiple times in multi output callback
fs = set(f for f in funcs if funcs.count(f) > 1)
same_callback.append((output, sorted(fs)))
if not all(funcs[0] == f for f in funcs):
# Output used across multiple callbacks
diff_callback.append((output, sorted(set(funcs))))

if diff_callback:
errors = get_error_lines(diff_callback)
msg1 = '''
The following outputs have been assigned to multiple callbacks.

{}

An output can only be associated with a single callback function.
Try combining your inputs and callback functions together into one
function.'''.format(errors).replace(' ', '')

if same_callback:
errors = get_error_lines(same_callback)
msg2 = '''
The following outputs occur multiple times in a single multi-output
callback:

{}

Multi-output callbacks cannot target the same output more than
once.'''.format(errors).replace(' ', '')

sep = '\n' if msg1 and msg2 else ''
raise exceptions.DuplicateCallbackOutput(msg1 + sep + msg2)

def _validate_callback(self, output, inputs, state):
# pylint: disable=too-many-branches
layout = self._cached_layout or self._layout_value()
Expand All @@ -660,19 +729,6 @@ def _validate_callback(self, output, inputs, state):
'Same output and input: {}'.format(bad)
)

if is_multi:
if len(set(output)) != len(output):
raise exceptions.DuplicateCallbackOutput(
'Same output was used in a'
' multi output callback!\n Duplicates:\n {}'.format(
',\n'.join(
k for k, v in
((str(x), output.count(x)) for x in output)
if v > 1
)
)
)

if (layout is None and
not self.config.first('suppress_callback_exceptions',
'supress_callback_exceptions')):
Expand Down Expand Up @@ -787,49 +843,6 @@ def _validate_callback(self, output, inputs, state):
'elements' if len(state) > 1 else 'element'
).replace(' ', ''))

callback_id = _create_callback_id(output)

callbacks = set(itertools.chain(*(
x[2:-2].split('...')
if x.startswith('..')
else [x]
for x in self.callback_map
)))
ns = {
'duplicates': set()
}
if is_multi:
def duplicate_check():
ns['duplicates'] = callbacks.intersection(
str(y) for y in output
)
return ns['duplicates']
else:
def duplicate_check():
return callback_id in callbacks
if duplicate_check():
if is_multi:
msg = '''
Multi output {} contains an `Output` object
that was already assigned.
Duplicates:
{}
'''.format(
callback_id,
pprint.pformat(ns['duplicates'])
)
else:
msg = '''
You have already assigned a callback to the output
with ID "{}" and property "{}". An output can only have
a single callback function. Try combining your inputs and
callback functions together into one function.
'''.format(
output.component_id,
output.component_property
).replace(' ', '')
raise exceptions.DuplicateCallbackOutput(msg)

def _validate_callback_output(self, output_value, output):
valid = [str, dict, int, float, type(None), Component]

Expand Down Expand Up @@ -947,8 +960,6 @@ def _validate_value(val, index=None):
# relationships
# pylint: disable=dangerous-default-value
def callback(self, output, inputs=[], state=[]):
self._validate_callback(output, inputs, state)

callback_id = _create_callback_id(output)
multi = isinstance(output, (list, tuple))

Expand Down Expand Up @@ -1026,7 +1037,7 @@ def add_context(*args, **kwargs):
return jsonResponse

self.callback_map[callback_id]['callback'] = add_context

self._callback_list.append((output, inputs, state, func.__name__))
return add_context

return wrap_func
Expand Down Expand Up @@ -1375,6 +1386,7 @@ def run_server(self,
:param flask_run_options: Given to `Flask.run`
:return:
"""
self._setup()
debug = self.enable_dev_tools(
debug,
dev_tools_serve_dev_bundles,
Expand Down Expand Up @@ -1409,3 +1421,12 @@ def run_server(self,

self.server.run(port=port, debug=debug,
**flask_run_options)

def _setup(self):
"""Do setup required for both dev server and production WSGI server"""
self._validate_callbacks()

def get_wsgi_application(self, debug=False):
self._setup()
self.enable_dev_tools(debug)
return self.server
154 changes: 98 additions & 56 deletions tests/test_integration.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -580,6 +580,53 @@ def test_multi_output(self):
html.Div(id='output5')
])

@app.callback([Output('output1', 'children'), Output('output2', 'children')],
[Input('output-btn', 'n_clicks')],
[State('output-btn', 'n_clicks_timestamp')])
def on_click(n_clicks, n_clicks_timestamp):
if n_clicks is None:
raise PreventUpdate

return n_clicks, n_clicks_timestamp

self.startServer(app)
t = time.time()

btn = self.wait_for_element_by_id('output-btn')
btn.click()
time.sleep(1)

self.wait_for_text_to_equal('#output1', '1')
output2 = self.wait_for_element_by_css_selector('#output2')

self.assertGreater(int(output2.text), t)

def test_multi_output_duplicates(self):
app = dash.Dash(__name__)
app.scripts.config.serve_locally = True

app.layout = html.Div([
html.Button('OUTPUT', id='output-btn'),

html.Table([
html.Thead([
html.Tr([
html.Th('Output 1'),
html.Th('Output 2')
])
]),
html.Tbody([
html.Tr([html.Td(id='output1'), html.Td(id='output2')]),
])
]),

html.Div(id='output3'),
html.Div(id='output4'),
html.Div(id='output5')
])

bad_outputs = []

@app.callback([Output('output1', 'children'), Output('output2', 'children')],
[Input('output-btn', 'n_clicks')],
[State('output-btn', 'n_clicks_timestamp')])
Expand All @@ -599,63 +646,48 @@ def dummy_callback(n_clicks):
return 'Output 3: {}'.format(n_clicks)

# Test that a multi output can't be included in a single output
with self.assertRaises(DuplicateCallbackOutput) as context:
@app.callback(Output('output1', 'children'),
[Input('output-btn', 'n_clicks')])
def on_click_duplicate(n_clicks):
if n_clicks is None:
raise PreventUpdate
bad_outputs.append('output1.children')

return 'something else'
@app.callback(Output('output1', 'children'),
[Input('output-btn', 'n_clicks')])
def on_click_duplicate(n_clicks):
if n_clicks is None:
raise PreventUpdate

self.assertTrue('output1' in context.exception.args[0])
return 'something else'

# Test a multi output cannot contain a used single output
with self.assertRaises(DuplicateCallbackOutput) as context:
@app.callback([Output('output3', 'children'),
Output('output4', 'children')],
[Input('output-btn', 'n_clicks')])
def on_click_duplicate_multi(n_clicks):
if n_clicks is None:
raise PreventUpdate

return 'something else'

self.assertTrue('output3' in context.exception.args[0])
bad_outputs.append('output3.children')

with self.assertRaises(DuplicateCallbackOutput) as context:
@app.callback([Output('output5', 'children'),
Output('output5', 'children')],
[Input('output-btn', 'n_clicks')])
def on_click_same_output(n_clicks):
return n_clicks
@app.callback([Output('output3', 'children'),
Output('output4', 'children')],
[Input('output-btn', 'n_clicks')])
def on_click_duplicate_multi(n_clicks):
if n_clicks is None:
raise PreventUpdate

self.assertTrue('output5' in context.exception.args[0])
return 'something else'

with self.assertRaises(DuplicateCallbackOutput) as context:
@app.callback([Output('output1', 'children'),
Output('output5', 'children')],
[Input('output-btn', 'n_clicks')])
def overlapping_multi_output(n_clicks):
return n_clicks

self.assertTrue(
'{\'output1.children\'}' in context.exception.args[0]
or "set(['output1.children'])" in context.exception.args[0]
)
# Test multi output cannot include same output more than once
bad_outputs.append('output5.children')

self.startServer(app)
@app.callback([Output('output5', 'children'),
Output('output5', 'children')],
[Input('output-btn', 'n_clicks')])
def on_click_same_output(n_clicks):
return n_clicks

t = time.time()
@app.callback([Output('output1', 'children'),
Output('output5', 'children')],
[Input('output-btn', 'n_clicks')])
def overlapping_multi_output(n_clicks):
return n_clicks

btn = self.wait_for_element_by_id('output-btn')
btn.click()
time.sleep(1)
with self.assertRaises(DuplicateCallbackOutput) as context:
app._setup()

self.wait_for_text_to_equal('#output1', '1')
output2 = self.wait_for_element_by_css_selector('#output2')

self.assertGreater(int(output2.text), t)
for output in bad_outputs:
self.assertTrue(output in context.exception.args[0])

def test_with_custom_renderer(self):
app = dash.Dash(__name__)
Expand Down Expand Up @@ -880,24 +912,34 @@ def test_output_input_invalid_callback(self):
html.Div(id='out')
])

@app.callback(Output('input-output', 'children'),
[Input('input-output', 'children')])
def failure(children):
pass

with self.assertRaises(CallbackException) as context:
@app.callback(Output('input-output', 'children'),
[Input('input-output', 'children')])
def failure(children):
pass
app._setup()

self.assertEqual(
'Same output and input: input-output.children',
context.exception.args[0]
)

# Multi output version.
def test_multi_output_input_invalid_callback(self):
app = dash.Dash(__name__)
app.layout = html.Div([
html.Div('child', id='input-output'),
html.Div(id='out')
])

@app.callback([Output('out', 'children'),
Output('input-output', 'children')],
[Input('input-output', 'children')])
def failure2(children):
pass

with self.assertRaises(CallbackException) as context:
@app.callback([Output('out', 'children'),
Output('input-output', 'children')],
[Input('input-output', 'children')])
def failure2(children):
pass
app._setup()

self.assertEqual(
'Same output and input: input-output.children',
Expand Down