mesh-sdk/go/publish/publish_test.go

package publish

import (
	"bytes"
	"context"
	"crypto/sha256"
	"encoding/base64"
	"encoding/hex"
	"encoding/json"
	"io"
	"strings"
	"testing"

	"git.novox.be/novox/mesh-contracts/go/parts/registry"
)

// A file travels to a registry seat in parts (ADR 0611, design 51 *Publishing*; SDK-1): only the parts the holder says
// it lacks are read and sent, each in chunks of at most MaxChunk in sequence with the last marked, so a cut transfer
// opened again goes on from what the holder holds; a part whose bytes are not its digest is refused before any of it
// travels.
func TestAFileTravelsInTheParts(t *testing.T) {
	big := bytes.Repeat([]byte("x"), MaxChunk+10)
	small, empty := []byte("config"), []byte{}
	part := func(b []byte, opened *int) Part {
		sum := sha256.Sum256(b)
		return Part{Digest: "sha256:" + hex.EncodeToString(sum[:]), Size: int64(len(b)),
			Open: func() (io.ReadCloser, error) { *opened++; return io.NopCloser(bytes.NewReader(b)), nil }}
	}
	type chunk struct {
		part string
		seq  int64
		last bool
		data []byte
	}
	holder := func(lacks []string, got *[]chunk, asked *[]string) Call {
		return func(key string, body any) (json.RawMessage, error) {
			*asked = append(*asked, key)
			raw, _ := json.Marshal(body)
			switch key {
			case "seat:oci-artifact-registry.publish":
				return json.Marshal(registry.PublishAnswer{Transfer: "t1", Lacks: lacks, Held: len(lacks) == 0})
			case "seat:oci-artifact-registry.publish-part":
				var in registry.PublishPartInput
				_ = json.Unmarshal(raw, &in)
				data, _ := base64.StdEncoding.DecodeString(in.Data)
				if len(raw) > 1<<20 {
					t.Errorf("a chunk's message is %d bytes, over the bus's largest", len(raw))
				}
				*got = append(*got, chunk{in.Part, in.Sequence, in.Last, data})
				return json.Marshal(registry.PublishPartAnswer{Transfer: in.Transfer, Part: in.Part})
			}
			t.Fatalf("asked %s", key)
			return nil, nil
		}
	}
	in := registry.PublishInput{Transfer: "t1", Name: "files", Kind: "archive", Digest: "sha256:" + strings.Repeat("a", 64)}
	var opens [3]int
	parts := []Part{part(big, &opens[0]), part(small, &opens[1]), part(empty, &opens[2])}

	for _, c := range []struct {
		name   string
		lacks  []int
		chunks int
		err    string
	}{
		{"a fresh transfer sends every part, the big one in two chunks and the empty one as one", []int{0, 1, 2}, 4, ""},
		{"a cut transfer opened again sends only what the holder lacks", []int{2}, 1, ""},
		{"a digest the holder holds sends nothing", nil, 0, ""},
	} {
		opens = [3]int{}
		var lacks []string
		for _, i := range c.lacks {
			lacks = append(lacks, parts[i].Digest)
		}
		var got []chunk
		var asked []string
		sent, err := Publish(context.Background(), holder(lacks, &got, &asked), "oci-artifact-registry", in, parts)
		if err != nil || sent.Chunks != c.chunks || len(got) != c.chunks || len(sent.Parts) != len(c.lacks) {
			t.Errorf("%s: sent %+v, %d chunks heard, %v", c.name, sent, len(got), err)
			continue
		}
		for i := range parts {
			want := 0
			for _, l := range c.lacks {
				if l == i {
					want = 2 // read once to check its digest, once to send it
				}
			}
			if opens[i] != want {
				t.Errorf("%s: part %d read %d times, want %d", c.name, i, opens[i], want)
			}
		}
		whole := map[string][]byte{}
		for i, ch := range got {
			whole[ch.part] = append(whole[ch.part], ch.data...)
			lastOfPart := i == len(got)-1 || got[i+1].part != ch.part
			if ch.last != lastOfPart || (i > 0 && got[i-1].part == ch.part && got[i-1].seq+1 != ch.seq) {
				t.Errorf("%s: chunk %d of %s is %d, last %v", c.name, i, ch.part[:12], ch.seq, ch.last)
			}
		}
		for _, l := range c.lacks {
			if p := parts[l]; int64(len(whole[p.Digest])) != p.Size {
				t.Errorf("%s: part %d arrived as %d bytes of %d", c.name, l, len(whole[p.Digest]), p.Size)
			}
		}
	}

	// A part whose bytes are not its digest travels not at all; a part the holder names that the transfer does not is
	// refused, naming it.
	liar := part(small, &opens[1])
	liar.Digest = parts[0].Digest
	var got []chunk
	var asked []string
	if _, err := Publish(context.Background(), holder([]string{liar.Digest}, &got, &asked), "oci-artifact-registry", in,
		[]Part{liar}); err == nil || len(got) != 0 || !strings.Contains(err.Error(), "nothing of it is sent") {
		t.Errorf("a part not its digest: %v, %d chunks sent", err, len(got))
	}
	if _, err := Publish(context.Background(), holder([]string{"sha256:" + strings.Repeat("f", 64)}, &got, &asked),
		"oci-artifact-registry", in, parts); err == nil || !strings.Contains(err.Error(), "does not name") {
		t.Errorf("a part the transfer does not name: %v", err)
	}
}