server/internal/client/ollama: confirm all chunksums were received (#9893)

If the chunksums response is missing a chunk, the client should fail
the download. This changes the client to check that all bytes are
accounted for in the chunksums response.

It is possible there are overlaps or gaps in the chunksums response and
so the size is not the only thing left to check, but this provides
enough coverage for now. We may want to check that chunks are contiguous
later.

server/internal/client/ollama/registry_test.go

@@ -17,6 +17,7 @@ import (
 	"reflect"
 	"slices"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
@@ -56,21 +57,21 @@ func (rr recordRoundTripper) RoundTrip(req *http.Request) (*http.Response, error
 
 // newClient constructs a cache with predefined manifests for testing. The manifests are:
 //
-//	empty: no data
-//	zero: no layers
-//	single: one layer with the contents "exists"
-//	multiple: two layers with the contents "exists" and "here"
-//	notfound: a layer that does not exist in the cache
-//	null: one null layer (e.g. [null])
-//	sizemismatch: one valid layer, and one with a size mismatch (file size is less than the reported size)
-//	invalid: a layer with invalid JSON data
+//	empty:         no data
+//	zero:          no layers
+//	single:        one layer with the contents "exists"
+//	multiple:      two layers with the contents "exists" and "here"
+//	notfound:      a layer that does not exist in the cache
+//	null:          one null layer (e.g. [null])
+//	sizemismatch:  one valid layer, and one with a size mismatch (file size is less than the reported size)
+//	invalid:       a layer with invalid JSON data
 //
 // Tests that want to ensure the client does not communicate with the upstream
 // registry should pass a nil handler, which will cause a panic if
 // communication is attempted.
 //
 // To simulate a network error, pass a handler that returns a 499 status code.
-func newClient(t *testing.T, h http.HandlerFunc) (*Registry, *blob.DiskCache) {
+func newClient(t *testing.T, upstreamRegistry http.HandlerFunc) (*Registry, *blob.DiskCache) {
 	t.Helper()
 
 	c, err := blob.Open(t.TempDir())
@@ -88,7 +89,7 @@ func newClient(t *testing.T, h http.HandlerFunc) (*Registry, *blob.DiskCache) {
 	r := &Registry{
 		Cache: c,
 		HTTPClient: &http.Client{
-			Transport: recordRoundTripper(h),
+			Transport: recordRoundTripper(upstreamRegistry),
 		},
 	}
 
@@ -767,3 +768,74 @@ func TestUnlink(t *testing.T) {
 		}
 	})
 }
+
+func TestPullChunksums(t *testing.T) {
+	check := testutil.Checker(t)
+
+	content := "hello"
+	var chunksums string
+	contentDigest := func() blob.Digest {
+		return blob.DigestFromBytes(content)
+	}
+	rc, c := newClient(t, func(w http.ResponseWriter, r *http.Request) {
+		switch {
+		case strings.Contains(r.URL.Path, "/manifests/latest"):
+			fmt.Fprintf(w, `{"layers":[{"digest":%q,"size":%d}]}`, contentDigest(), len(content))
+		case strings.HasSuffix(r.URL.Path, "/chunksums/"+contentDigest().String()):
+			loc := fmt.Sprintf("http://blob.store/v2/library/test/blobs/%s", contentDigest())
+			w.Header().Set("Content-Location", loc)
+			io.WriteString(w, chunksums)
+		case strings.Contains(r.URL.Path, "/blobs/"+contentDigest().String()):
+			http.ServeContent(w, r, contentDigest().String(), time.Time{}, strings.NewReader(content))
+		default:
+			t.Errorf("unexpected request: %v", r)
+			http.NotFound(w, r)
+		}
+	})
+
+	rc.MaxStreams = 1        // prevent concurrent chunk downloads
+	rc.ChunkingThreshold = 1 // for all blobs to be chunked
+
+	var mu sync.Mutex
+	var reads []int64
+	ctx := WithTrace(t.Context(), &Trace{
+		Update: func(l *Layer, n int64, err error) {
+			t.Logf("Update: %v %d %v", l, n, err)
+			mu.Lock()
+			reads = append(reads, n)
+			mu.Unlock()
+		},
+	})
+
+	chunksums = fmt.Sprintf("%s 0-2\n%s 3-4\n",
+		blob.DigestFromBytes("hel"),
+		blob.DigestFromBytes("lo"),
+	)
+	err := rc.Pull(ctx, "test")
+	check(err)
+	if !slices.Equal(reads, []int64{0, 3, 5}) {
+		t.Errorf("reads = %v; want %v", reads, []int64{0, 3, 5})
+	}
+
+	mw, err := rc.Resolve(t.Context(), "test")
+	check(err)
+	mg, err := rc.ResolveLocal("test")
+	check(err)
+	if !reflect.DeepEqual(mw, mg) {
+		t.Errorf("mw = %v; mg = %v", mw, mg)
+	}
+	for i := range mg.Layers {
+		_, err = c.Get(mg.Layers[i].Digest)
+		if err != nil {
+			t.Errorf("Get(%v): %v", mg.Layers[i].Digest, err)
+		}
+	}
+
+	// missing chunks
+	content = "llama"
+	chunksums = fmt.Sprintf("%s 0-1\n", blob.DigestFromBytes("ll"))
+	err = rc.Pull(ctx, "missingchunks")
+	if err == nil {
+		t.Error("expected error because of missing chunks")
+	}
+}