reflectors

var Cell = cell.Module(
	"loadbalancer-reflectors",
	"Reflects external state to load-balancing tables",

	K8sReflectorCell,

	FileReflectorCell,
)

var FileReflectorCell = cell.Module(
	"file-reflector",
	"Synchronizes load-balancing state from a file",

	cell.Config(fileReflectorConfig{}),
	cell.Invoke(registerFileReflector),
)

FileReflectorCell synchronizes the load-balancing state from a file specified with --lb-state-file. The file format is specified by StateFile and consists of Kubernetes services and endpoint slices.

The Kubernetes definitions are used to avoid having a new format and conversions from that format and it is also familiar to users.

The implementation is tested by 'pkg/loadbalancer/tests/testdata/file.txtar' which also shows an example of the file format.

var K8sReflectorCell = cell.Module(
	"k8s-reflector",
	"Reflects load-balancing state from Kubernetes",

	cell.ProvidePrivate(resourcesToStreams),
	cell.Invoke(RegisterK8sReflector),
)

K8sReflectorCell reflects Kubernetes Service and EndpointSlice objects to the load-balancing tables.

Note that this implementation uses Resource[*Service] and Resource[*Endpoints], which is not the desired end-game as we'll hold onto the same data multiple times. We should instead have a reflector that is built directly on the client-go reflector (k8s.RegisterReflector) and not populate an intermediate cache.Store. But as we're still experimenting it's easier to build on what already exists.