type Frontend interface {
	Solve(ctx context.Context, llb FrontendLLBBridge, opt map[string]string) (*Result, error)
}

type FrontendLLBBridge interface {
	Solve(ctx context.Context, req SolveRequest) (*Result, error)
	ResolveImageConfig(ctx context.Context, ref string, opt gw.ResolveImageConfigOpt) (digest.Digest, []byte, error)
	Exec(ctx context.Context, meta executor.Meta, rootfs cache.ImmutableRef, stdin io.ReadCloser, stdout, stderr io.WriteCloser) error
}

type Result struct {
	Ref      solver.CachedResult
	Refs     map[string]solver.CachedResult
	Metadata map[string][]byte
}

type SolveRequest = gw.SolveRequest

type WorkerInfos interface {
	WorkerInfos() []client.WorkerInfo
}