aghast

A Go Home Automation SysTem (AGHAST)

AGHAST is primarily an MQTT-centric automation server - it does not mandate a specific front-end.

It provides two main services: an automation engine, and a set of MQTT helpers to aid in the control and monitoring of a disparate collection of MQTT devices.

All data and controls that should be provided to end-users (i.e. not administrators) are exposed via MQTT. Node-Red is being used as a front-end during development and some example flows are provided, but other MQTT-connected dashboards could be used if prefered.

We believe that end-users of HA systems are generally not interested in the nuts and bolts, so configuration is performed entirely at the back-end by the in-house geek using TOML files ;-)

Requirements

• An MQTT Broker - development is being undertaken using Mosquitto, any modern broker should work
• An MQTT-Connected dashboard - Node-Red works well and example flows are included

Integrations

Integrations provide support for interacting with real-world or virtual resources, eg. Wifi lights, web scrapers, HVAC systems. All interaction is via MQTT.

Currently available Integrations...

The Time Integration must be enabled for AGHAST to start, you will also probably need to enable Automation and at least one other Integration in order to do anything useful.

The Tuya Integration is a bit of a hack. But... it can be used to integrate LIDL SmartHome ZigBee (and other ZigBee stuff) if they are first added to the TuyaSmart app. However, it's much better to use zigbee2mqtt with a supported USB dongle or hub.

Configuration

The main configuration file config.toml is quite simple, containing only some general information about the system itself, and a list of enabled Integrations, eg.

SystemName = "Our House"      # Label for the system
Postcode = "!!SECRET(postcode)"

MqttBroker = "!!CONSTANT(mqttBroker)"  # Hostname or IP of MQTT Broker
MqttPort = 1883               # MQTT Broker port
MqttClientID = "aghast"       # MQTT Client ID
MqttUsername = ""
MqttPassword = ""
MqttBaseTopic = "aghast"      # First element of topic for all messages we send

ControlPort = 46445           # HTTP port for back-end admin control

# List of Integrations we want enabled
Integrations = [
  "time",         # the Time integration MUST be enabled
  "automation",
#  "datalogger",  # Commented out, will not be enabled
  "hostchecker",
  "influx",
  "mqtt2smtp",
  "mqttcache",
  "mqttsender",
  "pimqttgpio",
  "postgres",
  "scraper",
#  "tuya",
]

All fields are required, although you can omit (rather than comment out) some Integrations if you prefer.

Every enabled Integration must have an associated <Integration>.toml configuration file or <Integration> subdirectory in the same directory, eg. time.toml, datalogger.toml, automation, etc.

A configuration is required for any enabled Integration, an empty <Integration>.toml configuration file or <Integration> subdirectory must exist.

When the server is started, it is passed only the configuration directory path. The structure of this directory is well-defined...

• One master configuration file with high-level info and list of enabled Integrations
• One configuration file per Integration
• Optional directories, named after an Integration, containing further configuration
• A directory of files each containing a single Automation
  • A subdirectory of the above containing any Action scripts

Eg.

ConfigDir/                   # any name - passed to server at startup
  config.toml                # integration configs
  time.toml
  hostchecker.toml
  influx.toml
  automations/               # automations
  |  officeWarmup.toml
  |  holidayLights.toml
  ...

Secrets and Constants

You may replace a value that you want to hide with the special string "!!SECRET(name)" (even if it is a number). AGHAST will then look for the matching name-value pair in the secrets.toml file and substitute the value found.

Similarly, you can replace a value with "!!CONSTANT(name)" and it will be fetched from the constants.toml file. This could be especially useful in Automations, where values might be reused several times.

Currently, secrets and constants are supported for string, integer and floating-point values.

Running

The AGHAST server may be started from the command line like this...

./aghastServer -configdir <path/to/config/dir>

The -configdir argument is compulsory and must refer to a directory containing the configuration files described above.

AGHAST is largely stateless (unless Integrations explicitly hold some state), it may be started and stopped without losing any data.
There is no intrinsic requirement for a database for the AGHAST core system.

A very simple systemd .service file is provided in the examples directory - you will at least need to alter the ExecStart= line to suit your circumstances.

MQTT Aide-Memoire

From time-to-time you may wish to manually purge any retained MQTT messages... mqtt-forget -t '+/#' -f