Action

An action is a node that runs when the flow reaches it: read a pin, move a servo, send a request, wait. It has an input on the left, outputs on the right, and settings in the inspector.

SettingsCopy Anchor Link

The node's fields — a pin, a number, a mode, a URL. Each one takes:

See Configurations.

What it publishesCopy Anchor Link

An action publishes values by name — GPIO's Read publishes value, DHT's Read publishes temperature and humidity. They're what later actions bind to, and what the debugger shows after it runs. Each has a type: int, float, bool, str, a list or an object.

By default an action hands the next one only what it published. With Pass Context on, it hands on what it was handed too — so the first action's output reaches the third.

The output it ends onCopy Anchor Link

Every action ends on one of its outputs, and the wire from that output decides what runs next:

• Success — it did what it does. Most actions have just this one (shown as Out).
• Custom outputs — an If's True / False, a Water Sensor's Wet / Dry, a Switch's cases.
• Fallback — it couldn't (no answer from the sensor, no network). Every action has it, so a failure can go somewhere on purpose.

An action whose output has nothing wired to it ends its branch.

On the boardCopy Anchor Link

An action is a MicroPython class: it reads its settings and what earlier actions published, does its work, publishes values and returns the output it ends on.

@action("gpio/read")
class ReadAction(HIOAction):

    async def execute(self, context):
        pin = context.get("read/pin")          # a setting
        if pin is None:
            return FALLBACK
        context.set("value", Pin(pin, Pin.IN).value() != 0)   # what it publishes
        return SUCCESS                         # the output it ends on

See Building a component.