VolumeSnapshot

Source: src/Fly/VolumeSnapshot.ts

A Fly.VolumeSnapshot is an on-demand snapshot of a mounted disk.

Create is fire-and-forget. Identity is the snapshot id from a subsequent list. Destroy is a no-op. Snapshots follow Volume retention. nuke skips this type.

Create a snapshot

Point it at a Volume id from the parent Machine or Service (mounts[0].volumeId).

const box = yield* Fly.Machine("Box", {
  app: Site,
  region: "iad",
  image: "nginx:alpine",
  mounts: [{ path: "/data", sizeGb: 1 }],
});

export const Nightly = Fly.VolumeSnapshot("Nightly", {
  app: Site,
  volumeId: box.mounts[0].volumeId,
});

Changing app or volumeId replaces the snapshot

A new snapshot is created. There is no delete API for the old one. It follows Volume snapshot_retention.

Restore

Restore into a new disk with snapshotId on the mount. Create-only. The new Machine gets a copy. The original Volume is unchanged.

const restored = yield* Fly.Machine("Restored", {
  app: Site,
  region: "iad",
  image: "nginx:alpine",
  mounts: [{ path: "/data", sizeGb: 1, snapshotId: Nightly.snapshotId }],
});

Restore into a Service

Pass snapshotId on MountVolume. Same create-only rule.

export default class Api extends Fly.Service<Api>()(
  "Api",
  { app: Site, main: import.meta.url, region: "iad", port: 3000 },
  Effect.gen(function* () {
    const disk = yield* Fly.MountVolume({
      path: "/data",
      sizeGb: 1,
      snapshotId: Nightly.snapshotId,
    });
    return {
      fetch: Effect.succeed(HttpServerResponse.text(disk.path)),
    };
  }).pipe(Effect.provide(Fly.MountVolumeLive)),
) {}