runtime

type Executor interface {
	// Start validates and compiles the module, then runs it in the
	// background. A missing module wraps ErrNotFound, an invalid one
	// ErrInvalid.
	Start(ctx context.Context, spec Spec) (Process, error)
	// Close releases the executor's resources.
	Close(ctx context.Context) error
}

type Process interface {
	// Wait blocks until the process ends.
	Wait() Result
	// Kill ends the process; Wait then reports Killed.
	Kill()
}

type Result struct {
	ExitCode int
	// TimedOut reports a wall-clock cancel.
	TimedOut bool
	// Killed reports a cancel through Process.Kill or the context.
	Killed bool
	// Error describes an abnormal end (a trap), empty on a normal exit.
	Error string
}

type Spec struct {
	// ID names the process in errors and logs.
	ID string
	// FS is the container's root filesystem, preopened as "/".
	FS *rootfs.FS
	// Path is the module's absolute path inside FS.
	Path string
	// Args is argv, Args[0] included.
	Args []string
	// Env is "KEY=value" entries.
	Env []string
	// Stdin, Stdout and Stderr default to empty / discard.
	Stdin          io.Reader
	Stdout, Stderr io.Writer
	// MemoryLimitBytes bounds the module's linear memory (0 = executor
	// default). It is rounded down to whole 64 KiB pages.
	MemoryLimitBytes int64
	// Timeout cancels the run after this wall-clock time (0 = none).
	Timeout time.Duration
}