hasmtools

A small tool to help me working with the Finite State Machine Sensor for Home Assistant by generating a png and converting the definition between JSON and YAML.

See https://github.com/edalquist/ha_state_machine for the Sensor.

Features

• write your definition in YAML instead of JSON
• convert from YAML to JSON and back
• generate an image of the state machine using graphviz

Examples

YAML input file

initial:
  a: state2
  b: state3
state2:
  a: initial
  b: state3
state3:
  a: initial
  b: state2

Note that in yaml the first state is the default/initial state.

Converted to JSON

 $ hasmtool example.yaml example.json

{
    "state": {
        "status": "initial"
    },
    "transitions": {
        "initial": {
            "a": "state2",
            "b": "state3"
        },
        "state2": {
            "a": "initial",
            "b": "state3"
        },
        "state3": {
            "a": "initial",
            "b": "state2"
        }
    }
}

Finally converted to PNG

 $ hasmtool example.json example.png

An example with timeouts

source: https://github.com/edalquist/ha_state_machine/blob/main/example.json

{
  "state": {
    "status": "IDLE"
  },
  "transitions": {
    "IDLE": {
      "above": "STARTING"
    },
    "STARTING": {
      "timeout": { "after": 6, "to": "RUNNING" },
      "below": "IDLE"
    },
    "RUNNING": {
      "below": "STOPPING"
    },
    "STOPPING": {
      "timeout": { "after": 15, "to": "DONE" },
      "above": "RUNNING",
      "middle": "RUNNING"
    },
    "DONE": {
      "timeout": { "after": 15, "to": "IDLE" }
    }
  }
}

Status

Working MVP.

Why Did I Do This?

It started with the desire to have a visualization of the FSM, then I realised I like yaml more than json for it, so one thing led to another...