joshuar-go-hass-agent/docs/development/README.md

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Go Hass Agent Development Notes

Development Environment

It is recommended to use Visual Studio Code. This project makes use of a Devcontainer to provide some convenience during development.

Open in Dev Containers

If using Visual Studio Code, you should be prompted when opening your cloned copy of the code to set up the dev container. The container contains an installation of Home Assistant and Mosquitto (MQTT broker) that can be used for testing. They should be started automatically.

Note that while you can also build and run the agent within the container environment, this will limit what sensors are reported and may even hinder development of new sensors. As such, it is recommended to build and run outside the container. You can still connect to Home Assistant running within the container, as it is exposed as per above.

Extending the Agent

Adding OS support

The intention of the agent design is to make it OS-agnostic.

Most OS specific code for fetching sensor data should likely be part of a GOARCH package and using filename suffixes such as filename_GOOS_GOARCH.go. See the files under linux/ as examples.

For some OSes, you might need some code to initialise or create some data source or API that the individual sensor fetching code uses. This code should be placed in device/, using filename suffixes such as filename_GOOS_GOARCH.go

For example, on Linux, a D-Bus connection is used for a lot of the sensor data gathering.

In such cases, you should pass this through as a value in a context. You can create the following function for your platform:

SetupContext(ctx context.Context) context.Context

It should accept a context.Context and derive its own context from this base that contains the necessary values for the platform. It will be propagated throughout the code wherever a context is passed and available for retrieval and use.

An example can be found in device/device_linux.go.