hostslot

type Capacity struct {
	Class string
	// Slots is the number of jobs of this class that may run at once. Zero
	// when Unlimited.
	Slots int
	// Unlimited means the limit is switched off (FORGE_<CLASS>_SLOTS=off):
	// Acquire returns at once and takes nothing.
	Unlimited bool
	// Source says where Slots came from, for the waiting line and
	// `forge slot status`.
	Source  string
	Machine Machine
}

type Holder struct {
	// Slot is the slot index; -1 for a waiter.
	Slot    int
	PID     int
	Command string
	Since   time.Time
	// Subtree is set when the holder's descendants count as inside its slot.
	Subtree bool
}

type Machine struct {
	// CPUs is the usable CPU count (a cgroup quota may make it fractional).
	CPUs float64
	// CPUSource names where CPUs came from: "cgroup cpu.max" or "nproc".
	CPUSource string
	// MemBytes is usable memory; 0 when it could not be read.
	MemBytes uint64
	// MemSource names where MemBytes came from: "cgroup memory.max",
	// "/proc/meminfo", "hw.memsize".
	MemSource string
}

type Options struct {
	// Dir is the slot directory; empty is $FORGE_SLOTS_DIR, else
	// <user cache dir>/forge/slots. Each class gets a subdirectory.
	Dir string
	// Slots overrides the capacity (a --slots flag). Zero resolves it with
	// CapacityFor: FORGE_<CLASS>_SLOTS, else the machine default.
	Slots int
	// Out receives the waiting lines. Nil waits silently.
	Out io.Writer
	// Label is the command recorded for this holder, shown to waiters. Empty
	// is this process's own command line.
	Label string
	// Subtree marks the holder as running the slot's work in child
	// processes, so every descendant counts as inside the slot even when its
	// environment lost FORGE_SLOT_HELD. Set it for wrappers and schedulers
	// that exec the work; leave it unset for a process that does the work
	// itself, so an unrelated child of a long-lived host is not exempted.
	Subtree bool
	// NoticeEvery is how often the waiting line repeats. Zero is 30s.
	NoticeEvery time.Duration
	// Poll is the mean interval between attempts while waiting, jittered
	// ±50%. Zero is 500ms.
	Poll time.Duration
	// Env is the environment read for FORGE_SLOT_HELD, FORGE_SLOTS_DIR and
	// FORGE_<CLASS>_SLOTS — normally os.Environ(). The package reads no
	// ambient variable itself, so a nil Env means none is set; in
	// particular, a caller that leaves it nil cannot see the slot its parent
	// passed it and will queue for one of its own.
	Env []string
}

type Report struct {
	Capacity Capacity
	// Dir is the class's slot directory.
	Dir     string
	Holders []Holder
	// Waiting is the queue, oldest first.
	Waiting []Holder
}

type Slot struct {
	// contains filtered or unexported fields
}