Support Arbitrary callbacks #2822

T4rk1n · 2024-03-29T18:09:01Z

Allow no output callback, resolve Allow for "null" / no output callbacks #1549
Add global set_props, resolve [Feature Request] Global set_props in backend callbacks. #2803
Fix side update pattern ids, fix [Long Callback] Support pattern matching for long callbacks side updates (progress/cancel/running) #2111

- Allow no output callback - Add global set_props - Fix side update pattern ids

ndrezn · 2024-04-08T15:12:51Z

Going to add a few more tests, then we should be almost there!

dash/_callback.py

dash/_utils.py

dash/_callback.py

dash/dash-renderer/src/actions/callbacks.ts

emilykl · 2024-04-22T20:17:13Z

dash/_callback.py

@@ -331,9 +337,12 @@ def wrap_func(func):
        def add_context(*args, **kwargs):
            output_spec = kwargs.pop("outputs_list")
            app_callback_manager = kwargs.pop("long_callback_manager", None)
-            callback_ctx = kwargs.pop("callback_context", {})
+            callback_ctx = kwargs.pop(
+                "callback_context", AttributeDict({"updated_props": {}})


Why does callback_ctx always need to contain an updated_props key?

I remember there is an error with some mocked tests.

emilykl · 2024-04-22T20:24:44Z

dash/_callback_context.py


 callback_context = CallbackContext()
+
+
+def set_props(component_id: typing.Union[str, dict], props: dict):


Is there a reason why the function signature for set_props isn't structured as 3 inputs: component_id, prop_name, value?

That to me seems more consistent with the rest of the Dash API.

It is the same signature as the frontend set_props, we considered set_props("id", prop=value) but decided to stay with same API for frontend and backend.

It's true, this pattern is a little more javascripty, but consistency is good and it could be convenient to be able to set multiple props of the same component in one call.

dash/dash-renderer/src/actions/dependencies.js

emilykl · 2024-04-22T20:36:34Z

dash/long_callback/_proxy_set_props.py

@@ -0,0 +1,7 @@
+class ProxySetProps(dict):


What's the purpose of ProxySetProps? Maybe add a comment at the top of the file.

It's a trick I found to make it work with background callbacks, when the value is set the handler is called and save the set_props data to be retrieved in the callback loop.

Does that mean background callbacks can update arbitrary props mid-execution and have that reflected in the app? If so that's super slick! Does it work to update the same prop(s) as the regular callback output(s), like progressive loading of the result?

Yes, the app is updated async like with the set_progress, it should be possible to update the same prop as the output.

emilykl · 2024-04-22T20:51:26Z

Aside from my comments, LGTM. ✨

In general there are a number of places where you've added separate code paths for no_output=True vs. no_output=False and I wonder whether some of them can be condensed down to a single code path... for example if we need to run some processing on the list of outputs, plausibly the same code should work on an empty list of outputs without the need for an if/else (or could be made to work with some small tweaks).

.pylintrc

alexcjohnson · 2024-04-24T14:08:05Z

dash/_callback_context.py

+    def set_props(self, component_id: typing.Union[str, dict], props: dict):
+        ctx_value = _get_context_value()
+        if isinstance(component_id, dict):
+            ctx_value.updated_props[json.dumps(component_id)] = props


Does plain json.dumps work here? It's not quite the same as we have for stringifying component IDs in the callback definition:

dash/dash/dependencies.py

Lines 46 to 59 in 9a4a479

def component_id_str(self):

i = self.component_id

def _dump(v):

return json.dumps(v, sort_keys=True, separators=(",", ":"))

def _json(k, v):

vstr = v.to_json() if hasattr(v, "to_json") else json.dumps(v)

return f"{json.dumps(k)}:{vstr}"

if isinstance(i, dict):

return "{" + ",".join(_json(k, i[k]) for k in sorted(i)) + "}"

return i

For set_props we don't need to handle wildcards, but I'd have thought we still want to sort keys and compress spaces.
(though looks like _dump there is unused and should be removed)

There is already a stringify_id here:

dash/dash/_utils.py

Lines 169 to 172 in 9a4a479

def stringify_id(id_):

if isinstance(id_, dict):

return json.dumps(id_, sort_keys=True, separators=(",", ":"))

return id_

I think the output is the same and is used in the base component, we should use the same everywhere.

alexcjohnson · 2024-04-24T14:16:29Z

dash/dash-renderer/src/actions/callbacks.ts

+function sideUpdate(outputs: any, dispatch: any) {
+    toPairs(outputs).forEach(([id, value]) => {
+        let componentId, propName;
+        if (id.includes('.')) {


Can't a dict ID contain .?

alexcjohnson · 2024-04-24T14:21:43Z

dash/dash.py

+            if cb.get("no_output"):
+                outputs_list = []
+            elif not outputs_list:
+                # FIXME Old renderer support?


Why do we want to support old renderer? Embedded? We should rebuild & test embedded with this update anyway.

That is what the comment on split_callback_id says for old embedded and new backend, it's pretty old now, maybe we can remove entirely.

dash/_callback.py

Support Arbitrary callbacks

3488bbe

- Allow no output callback - Add global set_props - Fix side update pattern ids

T4rk1n requested review from alexcjohnson and ndrezn as code owners March 29, 2024 18:09

T4rk1n added 2 commits April 2, 2024 13:03

Fix dvcv001

6623750

Fix test_grouped_callbacks.

2f84022

T4rk1n added 3 commits April 9, 2024 11:14

Add test arbitrary callbacks.

fb60ce0

Add test arbitrary callbacks for background callbacks.

a9f757c

Remove lock from test.

d6564d8

T4rk1n changed the title ~~[WIP] Support Arbitrary callbacks~~ Support Arbitrary callbacks Apr 11, 2024

ndrezn requested a review from emilykl April 15, 2024 15:04

ndrezn assigned emilykl Apr 15, 2024

Merge branch 'dev' into feat/global-set-props

cb84367

emilykl reviewed Apr 22, 2024

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emilykl reviewed Apr 22, 2024

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emilykl reviewed Apr 22, 2024

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T4rk1n added 5 commits April 23, 2024 09:03

reuse hashing

00baa48

reuse hashing

d57134b

Improve sideUpdate

f1a92a3

Add error when returning value in no output callbacks.

b1a0529

Add ProxySetProps docstring

dfdb605

alexcjohnson reviewed Apr 24, 2024

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T4rk1n added 5 commits April 24, 2024 11:18

use stringigfy_id

8891a71

rollback pylintrc change

939c010

fix stringify_id

b12c481

Fix case where the dict id contains a dot

dfaf5d1

Refactor no_output variable to has_output and less branching

6360421

T4rk1n requested a review from emilykl April 25, 2024 18:26

syl-oh reviewed Apr 25, 2024

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T4rk1n added 3 commits April 25, 2024 14:53

Update changelog

2b29699

Add no output counter test

a1e461f

reverse condition

ad73c29

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Support Arbitrary callbacks #2822

Support Arbitrary callbacks #2822

T4rk1n commented Mar 29, 2024

ndrezn commented Apr 8, 2024

emilykl Apr 22, 2024

T4rk1n Apr 23, 2024

emilykl Apr 22, 2024

T4rk1n Apr 23, 2024

alexcjohnson Apr 24, 2024

emilykl Apr 22, 2024

T4rk1n Apr 23, 2024

alexcjohnson Apr 24, 2024

T4rk1n Apr 24, 2024

emilykl commented Apr 22, 2024

alexcjohnson Apr 24, 2024

T4rk1n Apr 24, 2024

alexcjohnson Apr 24, 2024

alexcjohnson Apr 24, 2024

T4rk1n Apr 24, 2024


		callback_context = CallbackContext()


		def set_props(component_id: typing.Union[str, dict], props: dict):

	def component_id_str(self):
	i = self.component_id

	def _dump(v):
	return json.dumps(v, sort_keys=True, separators=(",", ":"))

	def _json(k, v):
	vstr = v.to_json() if hasattr(v, "to_json") else json.dumps(v)
	return f"{json.dumps(k)}:{vstr}"

	if isinstance(i, dict):
	return "{" + ",".join(_json(k, i[k]) for k in sorted(i)) + "}"

	return i

	def stringify_id(id_):
	if isinstance(id_, dict):
	return json.dumps(id_, sort_keys=True, separators=(",", ":"))
	return id_

Support Arbitrary callbacks #2822

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T4rk1n commented Mar 29, 2024

ndrezn commented Apr 8, 2024

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emilykl commented Apr 22, 2024

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