Packaging guidelines
buildHomeAssistantComponent
Custom components should be packaged using the
buildHomeAssistantComponent function, that is provided at top-level.
It builds upon buildPythonPackage but uses a custom install and check
phase.
Python runtime dependencies can be directly consumed as unqualified
function arguments. Pass them into dependencies, for them to
be available to Home Assistant.
Out-of-tree components need to use Python packages from
home-assistant.python.pkgs as to not introduce conflicting package
versions into the Python environment.
Example Boilerplate:
{
lib,
buildHomeAssistantComponent,
fetchFromGitHub,
}:
buildHomeAssistantComponent {
# owner, domain, version
src = fetchFromGithub {
# owner, repo, rev, hash
};
dependencies = [
# python requirements, as specified in manifest.json
];
meta = with lib; {
# changelog, description, homepage, license, maintainers
};
}
Package attribute
The attribute name must reflect the domain as seen in the
manifest.json, which in turn will match the python module name below
in the custom_components/ directory.
Example:
The project mweinelt/ha-prometheus-sensor
would receive the attribute name "prometheus_sensor", because both
domain in the manifest.json as well as the module name are
prometheus_sensor.
Package name
The pname attribute is a composition of both owner and domain.
Don't set pname, set owner and domain instead.
Exposing the domain attribute separately allows checking for
conflicting components at eval time.
Manifest check
The buildHomeAssistantComponent builder uses a hook to check whether
the dependencies specified in the manifest.json are present and
inside the specified version range. It also makes sure derivation
and manifest agree about the domain name.
There shouldn't be a need to disable this hook, but you can set
dontCheckManifest to true in the derivation to achieve that.
Too narrow version constraints
Every once in a while a dependency constraint is more narrow than it needs to be. Instead of applying brittle substitutions the version constraint can be ignored on a per requirement basis.
{
dependencies = [ pyemvue ];
# don't check the version constraint of pyemvue
ignoreVersionRequirement = [ "pyemvue" ];
}