package pathinfosvc
import (
"bufio"
"bytes"
"context"
"encoding/base64"
"fmt"
"io"
"net/http"
"net/url"
castorev1pb "code.tvl.fyi/tvix/castore/protos"
"code.tvl.fyi/tvix/nar-bridge/pkg/importer"
storev1pb "code.tvl.fyi/tvix/store/protos"
mh "github.com/multiformats/go-multihash/core"
"github.com/nix-community/go-nix/pkg/narinfo"
"github.com/nix-community/go-nix/pkg/nixbase32"
"github.com/nix-community/go-nix/pkg/nixpath"
"github.com/sirupsen/logrus"
"github.com/ulikunitz/xz"
"google.golang.org/grpc/codes"
"google.golang.org/grpc/status"
)
var _ storev1pb.PathInfoServiceServer = &PathInfoServiceServer{}
// PathInfoServiceServer exposes a Nix HTTP Binary Cache as a storev1pb.PathInfoServiceServer.
type PathInfoServiceServer struct {
storev1pb.UnimplementedPathInfoServiceServer
httpEndpoint *url.URL
httpClient *http.Client
// TODO: signatures
directoryServiceClient castorev1pb.DirectoryServiceClient
blobServiceClient castorev1pb.BlobServiceClient
}
func New(httpEndpoint *url.URL, httpClient *http.Client, directoryServiceClient castorev1pb.DirectoryServiceClient, blobServiceClient castorev1pb.BlobServiceClient) *PathInfoServiceServer {
return &PathInfoServiceServer{
httpEndpoint: httpEndpoint,
httpClient: httpClient,
directoryServiceClient: directoryServiceClient,
blobServiceClient: blobServiceClient,
}
}
// CalculateNAR implements storev1.PathInfoServiceServer.
// It returns PermissionDenied, as clients are supposed to calculate NAR hashes themselves.
func (*PathInfoServiceServer) CalculateNAR(context.Context, *castorev1pb.Node) (*storev1pb.CalculateNARResponse, error) {
return nil, status.Error(codes.PermissionDenied, "do it yourself please")
}
// Get implements storev1.PathInfoServiceServer.
// It only supports lookup my outhash, translates them to a corresponding GET $outhash.narinfo request,
// ingests the NAR file, while populating blob and directory service, then returns the PathInfo node.
// Subsequent requests will traverse the NAR file again, so make sure to compose this with another
// PathInfoService as caching layer.
func (p *PathInfoServiceServer) Get(ctx context.Context, getPathInfoRequest *storev1pb.GetPathInfoRequest) (*storev1pb.PathInfo, error) {
outputHash := getPathInfoRequest.GetByOutputHash()
if outputHash == nil {
return nil, status.Error(codes.Unimplemented, "only by output hash supported")
}
// construct NARInfo URL
narinfoURL := p.httpEndpoint.JoinPath(fmt.Sprintf("%v.narinfo", nixbase32.EncodeToString(outputHash)))
log := logrus.WithField("output_hash", base64.StdEncoding.EncodeToString(outputHash))
// We start right with a GET request, rather than doing a HEAD request.
// If a request to the PathInfoService reaches us, an upper layer *wants* it
// from us.
// Doing a HEAD first wouldn't give us anything, we can still react on the Not
// Found situation when doing the GET request.
niRq, err := http.NewRequestWithContext(ctx, "GET", narinfoURL.String(), nil)
if err != nil {
log.WithError(err).Error("unable to construct NARInfo request")
return nil, status.Errorf(codes.Internal, "unable to construct NARInfo request")
}
// Do the actual request; this follows redirects.
niResp, err := p.httpClient.Do(niRq)
if err != nil {
log.WithError(err).Error("unable to do NARInfo request")
return nil, status.Errorf(codes.Internal, "unable to do NARInfo request")
}
defer niResp.Body.Close()
// In the case of a 404, return a NotFound.
// We also return a NotFound in case of a 403 - this is to match the behaviour as Nix,
// when querying nix-cache.s3.amazonaws.com directly, rather than cache.nixos.org.
if niResp.StatusCode == http.StatusNotFound || niResp.StatusCode == http.StatusForbidden {
log.Warn("no NARInfo found")
return nil, status.Error(codes.NotFound, "no NARInfo found")
}
if niResp.StatusCode < 200 || niResp.StatusCode >= 300 {
log.WithField("status_code", niResp.StatusCode).Warn("Got non-success when trying to request NARInfo")
return nil, status.Errorf(codes.Internal, "got status code %v trying to request NARInfo", niResp.StatusCode)
}
// parse the NARInfo file.
narInfo, err := narinfo.Parse(niResp.Body)
if err != nil {
log.WithError(err).Warn("Unable to parse NARInfo")
return nil, status.Errorf(codes.Internal, "unable to parse NARInfo")
}
// close niResp.Body, we're not gonna read from there anymore.
_ = niResp.Body.Close()
// validate the NARInfo file. This ensures strings we need to parse actually parse,
// so we can just plain panic further down.
if err := narInfo.Check(); err != nil {
log.WithError(err).Warn("unable to validate NARInfo")
return nil, status.Errorf(codes.Internal, "unable to validate NARInfo: %s", err)
}
// only allow sha256 here. Is anything else even supported by Nix?
if narInfo.NarHash.HashType != mh.SHA2_256 {
log.Error("unsupported hash type")
return nil, status.Errorf(codes.Internal, "unsuported hash type in NarHash: %s", narInfo.NarHash.SRIString())
}
// TODO: calculate fingerprint, check with trusted pubkeys, decide what to do on mismatch
log = log.WithField("narinfo_narhash", narInfo.NarHash.SRIString())
log = log.WithField("nar_url", narInfo.URL)
// prepare the GET request for the NAR file.
narRq, err := http.NewRequestWithContext(ctx, "GET", p.httpEndpoint.JoinPath(narInfo.URL).String(), nil)
if err != nil {
log.WithError(err).Error("unable to construct NAR request")
return nil, status.Errorf(codes.Internal, "unable to construct NAR request")
}
log.Info("requesting NAR")
narResp, err := p.httpClient.Do(narRq)
if err != nil {
log.WithError(err).Error("error during NAR request")
return nil, status.Errorf(codes.Internal, "error during NAR request")
}
defer narResp.Body.Close()
// If we can't access the NAR file that the NARInfo is referring to, this is a store inconsistency.
// Propagate a more serious Internal error, rather than just a NotFound.
if narResp.StatusCode == http.StatusNotFound || narResp.StatusCode == http.StatusForbidden {
log.Error("Unable to find NAR")
return nil, status.Errorf(codes.Internal, "NAR at URL %s does not exist", narInfo.URL)
}
// wrap narResp.Body with some buffer.
// We already defer closing the http body, so it's ok to loose io.Close here.
var narBody io.Reader
narBody = bufio.NewReaderSize(narResp.Body, 10*1024*1024)
if narInfo.Compression == "none" {
// Nothing to do
} else if narInfo.Compression == "xz" {
narBody, err = xz.NewReader(narBody)
if err != nil {
log.WithError(err).Error("failed to open xz")
return nil, status.Errorf(codes.Internal, "failed to open xz")
}
} else {
log.WithField("nar_compression", narInfo.Compression).Error("unsupported compression")
return nil, fmt.Errorf("unsupported NAR compression: %s", narInfo.Compression)
}
directoriesUploader := importer.NewDirectoriesUploader(ctx, p.directoryServiceClient)
defer directoriesUploader.Done() //nolint:errcheck
blobUploaderCb := importer.GenBlobUploaderCb(ctx, p.blobServiceClient)
pathInfo, err := importer.Import(
ctx,
narBody,
func(blobReader io.Reader) ([]byte, error) {
blobDigest, err := blobUploaderCb(blobReader)
if err != nil {
return nil, err
}
log.WithField("blob_digest", base64.StdEncoding.EncodeToString(blobDigest)).Debug("upload blob")
return blobDigest, nil
},
func(directory *castorev1pb.Directory) ([]byte, error) {
directoryDigest, err := directoriesUploader.Put(directory)
if err != nil {
return nil, err
}
log.WithField("directory_digest", base64.StdEncoding.EncodeToString(directoryDigest)).Debug("upload directory")
return directoryDigest, nil
},
)
if err != nil {
log.WithError(err).Error("error during NAR import")
return nil, status.Error(codes.Internal, "error during NAR import")
}
// Close the directories uploader. This ensures the DirectoryService has
// properly persisted all Directory messages sent.
directoriesPutResponse, err := directoriesUploader.Done()
if err != nil {
log.WithError(err).Error("error during directory upload")
return nil, status.Error(codes.Internal, "error during directory upload")
}
// If we uploaded directories (so directoriesPutResponse doesn't return null),
// the RootDigest field in directoriesPutResponse should match the digest
// returned in importedPathInfo.
// This check ensures the directory service came up with the same root hash as we did.
if directoriesPutResponse != nil {
rootDigestPathInfo := pathInfo.GetNode().GetDirectory().GetDigest()
rootDigestDirectoriesPutResponse := directoriesPutResponse.GetRootDigest()
log := log.WithFields(logrus.Fields{
"root_digest_pathinfo": rootDigestPathInfo,
"root_digest_directories_put_resp": rootDigestDirectoriesPutResponse,
})
if !bytes.Equal(rootDigestPathInfo, rootDigestDirectoriesPutResponse) {
log.Errorf("returned root digest doesn't match what's calculated")
return nil, status.Error(codes.Internal, "error in root digest calculation")
}
}
// Compare NAR hash in the NARInfo with the one we calculated while reading the NAR
// We already checked above that the digest is in sha256.
importedNarSha256 := pathInfo.GetNarinfo().GetNarSha256()
if !bytes.Equal(narInfo.NarHash.Digest(), importedNarSha256) {
log := log.WithField("imported_nar_sha256", base64.StdEncoding.EncodeToString(importedNarSha256))
log.Error("imported digest doesn't match NARInfo digest")
return nil, fmt.Errorf("imported digest doesn't match NARInfo digest")
}
// annotate importedPathInfo with the rest of the metadata from NARINfo.
// extract the output hashes from narInfo.References into importedPathInfo.References.
{
// Length of the hash portion of the store path in base32.
encodedPathHashSize := nixbase32.EncodedLen(20)
for _, referenceStr := range narInfo.References {
if len(referenceStr) < encodedPathHashSize {
return nil, fmt.Errorf("reference string '%s' is too small", referenceStr)
}
decodedReferenceHash, err := nixbase32.DecodeString(referenceStr[0:encodedPathHashSize])
if err != nil {
return nil, fmt.Errorf("unable to decode reference string '%s': %w", referenceStr, err)
}
pathInfo.References = append(pathInfo.References, decodedReferenceHash)
}
}
pathInfo.Narinfo.ReferenceNames = narInfo.References
for _, signature := range narInfo.Signatures {
pathInfo.Narinfo.Signatures = append(pathInfo.Narinfo.Signatures, &storev1pb.NARInfo_Signature{
Name: signature.Name,
Data: signature.Data,
})
}
// set the root node name to the basename of the output path in the narInfo.
// currently the root node has no name yet.
outPath, err := nixpath.FromString(narInfo.StorePath)
if err != nil {
// unreachable due to nixpath.Check()
panic(err)
}
newName := []byte(nixbase32.EncodeToString(outPath.Digest) + "-" + string(outPath.Name))
// set the root name in all three cases.
if node := pathInfo.Node.GetDirectory(); node != nil {
node.Name = newName
} else if node := pathInfo.Node.GetFile(); node != nil {
node.Name = newName
} else if node := pathInfo.Node.GetSymlink(); node != nil {
node.Name = newName
} else {
panic("node may not be nil")
}
return pathInfo, nil
// TODO: Deriver, System, CA
}
// List implements storev1.PathInfoServiceServer.
// It returns a permission denied, because normally you can't get a listing
func (*PathInfoServiceServer) List(*storev1pb.ListPathInfoRequest, storev1pb.PathInfoService_ListServer) error {
return status.Error(codes.Unimplemented, "unimplemented")
}
// Put implements storev1.PathInfoServiceServer.
func (*PathInfoServiceServer) Put(context.Context, *storev1pb.PathInfo) (*storev1pb.PathInfo, error) {
return nil, status.Error(codes.Unimplemented, "unimplemented")
}
