Draw every flow as one graph, merged on what it talks to

A node type can now say which outside thing its parameters point at, and nodes sharing one — a broker topic, a URL, a bucket — are drawn as a single neuron on a new /brain canvas. That makes the wiring which runs between flows through a broker visible for the first time; no single flow's canvas can show it. The key is read off stored parameters, so a credential reference never reaches an id. Layout is a d3 force simulation settled once and then frozen, lit by the socket the editor already listens to: a neuron pulses when any node behind it publishes, and its connections light as values pass. Fixes the message pulse while here: interpolating the stroke against the edge's `color-mix()` resting colour went through oklab and left the gamut, which turned every pulse on both canvases fluorescent yellow. Co-Authored-By: Claude Fable 5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_017MeiWk3Yq12n2pTvnQWYvt
2026-08-16 22:59:31 +02:00
parent af3ba51571
commit 4bcd38354b
25 changed files with 790 additions and 4 deletions
@@ -0,0 +1,82 @@
+"""Nodes talking to the same outside thing are one neuron, across flows.
+
+That merge is the whole point of the brain graph: a broker topic is a single
+physical thing, and two flows sharing one are wired together through it even
+though neither canvas can draw the other end.
+"""
+
+from pathlib import Path
+
+import pytest
+
+from app.flow.controller import FlowController
+from app.flow.messages import DType, MessageSpec
+from app.flow.nodes import MqttNode
+from app.flow.schemas import FlowDef, NodeDef
+from app.flow.store import FlowStore
+
+BROKER = {"broker_host": "mosquitto", "broker_port": 1883, "topic": "sensors/temp"}
+
+
+def subscriber(node_id: str) -> NodeDef:
+    return NodeDef(
+        id=node_id,
+        type="mqtt",
+        params=dict(BROKER),
+        provides=[MessageSpec(name="temp", dtype=DType.FLOAT)],
+    )
+
+
+@pytest.fixture
+def controller(tmp_path: Path) -> FlowController:
+    store = FlowStore(tmp_path / "flows")
+    store.write_flow(
+        FlowDef(
+            name="house",
+            nodes=[
+                subscriber("sensor"),
+                NodeDef(
+                    id="scale",
+                    type="change",
+                    requires=[MessageSpec(name="temp", dtype=DType.FLOAT)],
+                    provides=[MessageSpec(name="scaled", dtype=DType.FLOAT)],
+                ),
+            ],
+        )
+    )
+    store.write_flow(FlowDef(name="shed", nodes=[subscriber("sensor")]))
+    return FlowController(store)
+
+
+def test_two_flows_on_one_topic_are_one_neuron(controller: FlowController):
+    graph = controller.brain_graph()
+
+    merged = [node for node in graph.nodes if node.kind == "mqtt"]
+    assert len(merged) == 1
+    assert merged[0].id == "mqtt:mosquitto:1883/sensors/temp"
+    assert merged[0].members == ["house.sensor", "shed.sensor"]
+    assert merged[0].flows == ["house", "shed"]
+
+
+def test_a_node_with_no_outside_thing_stays_its_own(controller: FlowController):
+    graph = controller.brain_graph()
+
+    scale = next(node for node in graph.nodes if node.kind == "change")
+    assert scale.id == "house.scale"
+    assert scale.members == ["house.scale"]
+
+
+def test_an_edge_carries_the_qualified_message(controller: FlowController):
+    graph = controller.brain_graph()
+
+    assert [(edge.source, edge.target, edge.messages) for edge in graph.edges] == [
+        ("mqtt:mosquitto:1883/sensors/temp", "house.scale", ["house.temp"])
+    ]
+
+
+def test_a_credential_never_reaches_the_key():
+    # Stored params, so a secret is still a reference. Neither its name nor its
+    # value belongs in something the browser gets to see.
+    key = MqttNode.instance_key({**BROKER, "password": {"$secret": "broker_pw"}})
+
+    assert key == "mosquitto:1883/sensors/temp"