import type { Accelerator, DeviceId, LaunchPlan } from "../contracts"; /** * The single place device selection becomes a mechanism. * * Engines declare `plan.devices` abstractly; this translates that list into whatever the * accelerator and runtime actually need. Before this existed the same derivation lived in * four modules with four different key precedences (gpu-leases, process-utilities, * process-manager, backend-builder) — one of which resolved UUIDs against an empty GPU * list and so only ever saw the raw selector. */ /** Docker flags a launcher must add for this plan. Empty for process launches. */export interface DeviceRuntimeFlags {  readonly args: readonly string[];  readonly groupAdd: readonly string[];} const joined = (devices: readonly DeviceId[]): string => devices.join(","); /** Indices for accelerators whose tooling selects by ordinal rather than UUID. */const ordinals = (devices: readonly DeviceId[]): string =>  devices.map((device) => device.slice(device.lastIndexOf(":") + 1)).join(","); export const deviceEnvironment = (  accelerator: Accelerator,  devices: readonly DeviceId[],): Readonly<Record<string, string>> => {  if (devices.length === 0) return {};  switch (accelerator) {    case "cuda":      return { CUDA_VISIBLE_DEVICES: joined(devices) };    case "rocm":      // ROCR_ gates the runtime, HIP_ gates the HIP API; setting only one leaves the      // other seeing every card on the box.      return { HIP_VISIBLE_DEVICES: ordinals(devices), ROCR_VISIBLE_DEVICES: ordinals(devices) };    case "xpu":      return { ONEAPI_DEVICE_SELECTOR: `level_zero:${ordinals(devices)}` };    case "metal":    case "cpu":      // Metal exposes no device selection, and CPU has nothing to select.      return {};  }}; export const dockerFlagsFor = (  accelerator: Accelerator,  devices: readonly DeviceId[],): DeviceRuntimeFlags => {  if (devices.length === 0) return { args: [], groupAdd: [] };  switch (accelerator) {    case "cuda":      return { args: ["--gpus", `"device=${joined(devices)}"`], groupAdd: [] };    case "rocm":      return {        args: ["--device", "/dev/kfd", "--device", "/dev/dri", "--security-opt", "seccomp=unconfined"],        groupAdd: ["video", "render"],      };    case "xpu":      return { args: ["--device", "/dev/dri"], groupAdd: ["render"] };    case "metal":    case "cpu":      return { args: [], groupAdd: [] };  }}; /** * Fold device selection into a plan's environment. Runtime is taken from the plan: a * docker plan still gets the env vars (the container reads them) *plus* the flags the * launcher applies separately via `dockerFlagsFor`. */export const applyDevices = (plan: LaunchPlan, accelerator: Accelerator): LaunchPlan => ({  ...plan,  env: { ...plan.env, ...deviceEnvironment(accelerator, plan.devices) },});