about summary refs log tree commit diff
path: root/tvix/nar-bridge/pkg/http/narinfo_get.go
blob: 98d85744d895e8e974ed46c8c77d83bde7d64a59 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
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)
			}
		}
	})
}