package http import ( "bytes" "context" "encoding/base64" "encoding/hex" "errors" "fmt" "io" "io/fs" "net/http" "sync" castorev1pb "code.tvl.fyi/tvix/castore-go" 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" ) const ( narUrl = "/nar/{narhash:^([" + nixbase32.Alphabet + "]{52})$}.nar" ) func renderNar( ctx context.Context, log *log.Entry, directoryServiceClient castorev1pb.DirectoryServiceClient, blobServiceClient castorev1pb.BlobServiceClient, narHashDbMu *sync.Mutex, narHashDb map[string]*narData, w io.Writer, narHash *nixhash.Hash, headOnly bool, ) error { // look in the lookup table narHashDbMu.Lock() narData, found := narHashDb[narHash.SRIString()] narHashDbMu.Unlock() rootNode := narData.rootNode // if we didn't find anything, return 404. if !found { return fmt.Errorf("narHash not found: %w", fs.ErrNotExist) } // if this was only a head request, we're done. if headOnly { return nil } directories := make(map[string]*castorev1pb.Directory) // If the root node is a directory, ask the directory service for all directories if pathInfoDirectory := rootNode.GetDirectory(); pathInfoDirectory != nil { rootDirectoryDigest := pathInfoDirectory.GetDigest() log = log.WithField("root_directory", base64.StdEncoding.EncodeToString(rootDirectoryDigest)) directoryStream, err := directoryServiceClient.Get(ctx, &castorev1pb.GetDirectoryRequest{ ByWhat: &castorev1pb.GetDirectoryRequest_Digest{ Digest: rootDirectoryDigest, }, Recursive: true, }) if err != nil { return fmt.Errorf("unable to query directory stream: %w", err) } // For now, we just stream all of these locally and put them into a hashmap, // which is used in the lookup function below. for { directory, err := directoryStream.Recv() if err != nil { if err == io.EOF { break } return fmt.Errorf("unable to receive from directory stream: %w", err) } // calculate directory digest // TODO: do we need to do any more validation? directoryDgst, err := directory.Digest() if err != nil { return fmt.Errorf("unable to calculate directory digest: %w", err) } log.WithField("directory", base64.StdEncoding.EncodeToString(directoryDgst)).Debug("received directory node") directories[hex.EncodeToString(directoryDgst)] = directory } } // render the NAR file err := storev1pb.Export( w, rootNode, func(directoryDigest []byte) (*castorev1pb.Directory, error) { log.WithField("directory", base64.StdEncoding.EncodeToString(directoryDigest)).Debug("Get directory") directoryRefStr := hex.EncodeToString(directoryDigest) directory, found := directories[directoryRefStr] if !found { return nil, fmt.Errorf( "directory with hash %v does not exist: %w", directoryDigest, fs.ErrNotExist, ) } return directory, nil }, func(blobDigest []byte) (io.ReadCloser, error) { log.WithField("blob", base64.StdEncoding.EncodeToString(blobDigest)).Debug("Get blob") resp, err := blobServiceClient.Read(ctx, &castorev1pb.ReadBlobRequest{ Digest: blobDigest, }) if err != nil { return nil, fmt.Errorf("unable to get blob: %w", err) } // set up a pipe, let a goroutine write, return the reader. pR, pW := io.Pipe() go func() { for { chunk, err := resp.Recv() if errors.Is(err, io.EOF) { break } if err != nil { pW.CloseWithError(fmt.Errorf("receiving chunk: %w", err)) return } // write the received chunk to the writer part of the pipe if _, err := io.Copy(pW, bytes.NewReader(chunk.GetData())); err != nil { log.WithError(err).Error("writing chunk to pipe") pW.CloseWithError(fmt.Errorf("writing chunk to pipe: %w", err)) return } } pW.Close() }() return io.NopCloser(pR), nil }, ) if err != nil { return fmt.Errorf("unable to export nar: %w", err) } return nil } func registerNarGet(s *Server) { // produce a handler for rendering NAR files. genNarHandler := func(isHead bool) func(w http.ResponseWriter, r *http.Request) { return func(w http.ResponseWriter, r *http.Request) { defer r.Body.Close() ctx := r.Context() // parse the narhash sent in the request URL narHash, err := parseNarHashFromUrl(chi.URLParamFromCtx(ctx, "narhash")) if err != nil { log.WithError(err).WithField("url", r.URL).Error("unable to decode nar hash from url") w.WriteHeader(http.StatusBadRequest) _, err := w.Write([]byte("unable to decode nar hash from url")) if err != nil { log.WithError(err).Errorf("unable to write error message to client") } return } log := log.WithField("narhash_url", narHash.SRIString()) // TODO: inline more of that function here? err = renderNar(ctx, log, s.directoryServiceClient, s.blobServiceClient, &s.narDbMu, s.narDb, w, narHash, isHead) if err != nil { if errors.Is(err, fs.ErrNotExist) { w.WriteHeader(http.StatusNotFound) } else { log.WithError(err).Warn("unable to render nar") w.WriteHeader(http.StatusInternalServerError) } } } } s.handler.Head(narUrl, genNarHandler(true)) s.handler.Get(narUrl, genNarHandler(false)) }