package http import ( "context" "encoding/base64" "errors" "fmt" "io" "io/fs" "net/http" "strings" "sync" storev1pb "code.tvl.fyi/tvix/store-go" "github.com/go-chi/chi/v5" nixhash "github.com/nix-community/go-nix/pkg/hash" "github.com/nix-community/go-nix/pkg/nixbase32" log "github.com/sirupsen/logrus" "google.golang.org/grpc/codes" "google.golang.org/grpc/status" ) // renderNarinfo writes narinfo contents to a passed io.Writer, or a returns a // (wrapped) io.ErrNoExist error if something doesn't exist. // if headOnly is set to true, only the existence is checked, but no content is // actually written. func renderNarinfo( ctx context.Context, log *log.Entry, pathInfoServiceClient storev1pb.PathInfoServiceClient, narHashToPathInfoMu *sync.Mutex, narHashToPathInfo map[string]*narData, outputHash []byte, w io.Writer, headOnly bool, ) error { pathInfo, err := pathInfoServiceClient.Get(ctx, &storev1pb.GetPathInfoRequest{ ByWhat: &storev1pb.GetPathInfoRequest_ByOutputHash{ ByOutputHash: outputHash, }, }) if err != nil { st, ok := status.FromError(err) if ok { if st.Code() == codes.NotFound { return fmt.Errorf("output hash %v not found: %w", base64.StdEncoding.EncodeToString(outputHash), fs.ErrNotExist) } return fmt.Errorf("unable to get pathinfo, code %v: %w", st.Code(), err) } return fmt.Errorf("unable to get pathinfo: %w", err) } log = log.WithField("pathInfo", pathInfo) if _, err := pathInfo.Validate(); err != nil { log.WithError(err).Error("unable to validate PathInfo") return fmt.Errorf("unable to validate PathInfo: %w", err) } if pathInfo.GetNarinfo() == nil { log.Error("PathInfo doesn't contain Narinfo field") return fmt.Errorf("PathInfo doesn't contain Narinfo field") } // extract the NARHash. This must succeed, as Validate() did succeed. narHash, err := nixhash.FromHashTypeAndDigest(0x12, pathInfo.GetNarinfo().GetNarSha256()) if err != nil { panic("must parse NarHash") } // add things to the lookup table, in case the same process didn't handle the NAR hash yet. narHashToPathInfoMu.Lock() narHashToPathInfo[narHash.SRIString()] = &narData{ rootNode: pathInfo.GetNode(), narSize: pathInfo.GetNarinfo().GetNarSize(), } narHashToPathInfoMu.Unlock() if headOnly { return nil } // convert the PathInfo to NARInfo. narInfo, err := ToNixNarInfo(pathInfo) // Write it out to the client. _, err = io.Copy(w, strings.NewReader(narInfo.String())) if err != nil { return fmt.Errorf("unable to write narinfo to client: %w", err) } return nil } func registerNarinfoGet(s *Server) { // GET $outHash.narinfo looks up the PathInfo from the tvix-store, // and then render a .narinfo file to the client. // It will keep the PathInfo in the lookup map, // so a subsequent GET /nar/ $narhash.nar request can find it. s.handler.Get("/{outputhash:^["+nixbase32.Alphabet+"]{32}}.narinfo", func(w http.ResponseWriter, r *http.Request) { defer r.Body.Close() ctx := r.Context() log := log.WithField("outputhash", chi.URLParamFromCtx(ctx, "outputhash")) // parse the output hash sent in the request URL outputHash, err := nixbase32.DecodeString(chi.URLParamFromCtx(ctx, "outputhash")) if err != nil { log.WithError(err).Error("unable to decode output hash from url") w.WriteHeader(http.StatusBadRequest) _, err := w.Write([]byte("unable to decode output hash from url")) if err != nil { log.WithError(err).Errorf("unable to write error message to client") } return } err = renderNarinfo(ctx, log, s.pathInfoServiceClient, &s.narDbMu, s.narDb, outputHash, w, false) if err != nil { if errors.Is(err, fs.ErrNotExist) { w.WriteHeader(http.StatusNotFound) } else { log.WithError(err).Warn("unable to render narinfo") w.WriteHeader(http.StatusInternalServerError) } } }) }