stroblme
cfb9e53d68
The store rewrites `"type": "trigger"` to `debounce` in every published and draft flow when it opens, bumps the version and commits once. No alias stays behind, so `trigger` is now an unknown type.
129 lines
4.6 KiB
Python
129 lines
4.6 KiB
Python
"""Debounce: send one thing now, another if nothing follows.
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Node-RED calls this node *trigger*. The shape it exists for is "the door
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opened — turn the light on, and off again in two minutes unless it opens
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again", which is awkward to express any other way.
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"""
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from __future__ import annotations
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import logging
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from collections.abc import Iterable
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from typing import Any
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from pydantic import BaseModel, ConfigDict, Field
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from fluksio.flow.messages import MessageSpec
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from fluksio.flow.nodes.base import Node
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logger = logging.getLogger(__name__)
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class DebounceNode(Node):
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"""Emit ``first`` on arrival, then ``then`` once the wait runs out.
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A value arriving during the wait extends it, so the second emission only
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happens when things have actually gone quiet. ``passthrough`` sends the
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incoming value instead of ``first``, and ``wait_port`` names an input
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carrying the wait, for the case where how long to wait is itself a value —
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a shutter that takes 26 s up and 28 s down.
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"""
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class Params(BaseModel):
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model_config = ConfigDict(extra="allow")
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first: Any = Field(default=True, description="Sent as soon as a value arrives.")
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then: Any = Field(
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default=False,
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description="Sent when the wait expires. Empty sends nothing.",
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)
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wait: float = Field(
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default=60.0, gt=0, description="Seconds of quiet before the second value."
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)
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extend: bool = Field(
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default=True,
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description="A value arriving during the wait starts it over.",
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)
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passthrough: bool = Field(
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default=False,
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description="Send the incoming value instead of 'first'.",
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)
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wait_port: str = Field(
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default="",
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description=(
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"An input port carrying the wait in seconds, for a wait that "
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"differs per message. Zero or less sends nothing afterwards."
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),
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)
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__slots__ = ("cfg",)
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def __init__(
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self,
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requires: MessageSpec | Iterable[MessageSpec] = (),
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provides: MessageSpec | Iterable[MessageSpec] = (),
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params: dict[str, Any] | None = None,
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name: str | None = None,
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):
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self.cfg = self.Params.model_validate(params or {})
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super().__init__(
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f=self._debounce,
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requires=requires,
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provides=provides,
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params=params,
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name=name or "debounce",
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)
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def _outputs(self, value: Any) -> dict[str, Any]:
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return {spec.port: value for spec in self.output_ports}
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def _debounce(self, params: dict[str, Any], **kwargs: Any) -> dict[str, Any] | None:
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if not kwargs or not self.output_ports:
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return None
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wait = self.cfg.wait
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if self.cfg.wait_port:
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# A value port rather than a setting: a shutter's run-time differs
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# by direction, and that is a message the graph carries.
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wait = float(kwargs.get(self.cfg.wait_port, wait) or 0)
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armed = self.recall("armed", 0)
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if armed and not self.cfg.extend:
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# Already counting down and not extending: ignore the new value.
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return None
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# A generation counter, so a value arriving mid-wait invalidates the
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# deferred emission that was already scheduled. Bumped even when this
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# message asks for no second value, which is how a wait is cancelled.
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generation = int(self.recall("generation", 0)) + 1
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self.remember("generation", generation)
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self.remember("armed", 1 if wait > 0 else 0)
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if self.cfg.then is not None and self._pipeline is not None and wait > 0:
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deferred = self._outputs(self.cfg.then)
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scheduled = self._pipeline.defer(
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self,
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self._to_messages(deferred) or {},
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wait,
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guard=("generation", generation),
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)
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if not scheduled:
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logger.warning(
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"Node '%s' cannot wait without a work queue; sending only "
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"its first value",
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self.name,
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)
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self.remember("armed", 0)
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if self.cfg.passthrough:
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# Whatever woke the node, minus the port that only said how long
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# to wait. Several inputs are ambiguous, so the first one wins.
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values = {
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port: value
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for port, value in kwargs.items()
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if port != self.cfg.wait_port
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}
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if values:
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return self._outputs(next(iter(values.values())))
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return self._outputs(self.cfg.first)
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