resource

type CPUUser interface {
	// CPUUsage returns the number of CPU cores of usage this user has attributed
	// to it.
	//
	// For example, if this user is reporting a process's CPU utilization and
	// that process is currently using 150% CPU (i.e. one and a half cores of
	// compute) then the return value will be 1.5.
	CPUUsage() float64
}

type DiskUser interface {
	// DiskUsage returns the number of bytes per second read from/written to
	// disk recently.
	DiskUsage() (read float64, write float64)

	// returns number of bytes available in the db volume
	AvailableDiskBytes() uint64
}

type Manager interface {
	User
	ProcessTracker

	// Shutdown allocated resources and stop tracking all processes.
	Shutdown()
}

type ProcessTracker interface {
	// TrackProcess adds [pid] to the list of processes that this tracker is
	// currently managing. Duplicate requests are dropped.
	TrackProcess(pid int)

	// UntrackProcess removes [pid] from the list of processes that this tracker
	// is currently managing. Untracking a currently untracked [pid] is a noop.
	UntrackProcess(pid int)
}

type User interface {
	CPUUser
	DiskUser
}