Bundle-uri capability: Only advertise when bundle exist

This MR is a building block towards enabling bundle-uri feature.

Here we modify the way bundle-uri capability is advertised to the client to only make it so when a bundle exist for the given repository.

For SSH, this change does not provide much benefit since the whole packfile negociation flow is performed on a single connection. In other words, the flow starts when the client starts the upload-pack service, and it ends when the client received all the objects it needed.

For SmartHTTP, however, this is different. Each request/command sent by the client (ls-refs, bundle-uri, fetch) is sent on different, stateless, RPC calls. There is no way to know what command the client is sending to the git-upload-pack process until that process is actually started, which means that the Git config injected into the process must be computed in advance for every request; this implies computing the SignedURL of the bundle if it exist. By advertising bundle-uri capability only when a bundle exists for the given repository, we make sure the client won't send a bundle-uri command if no bundle exist.

This not only reduces by 1 the number of round-trip request and the number of Git config computation, but it also make it easier to monitor the use of bundle-uri feature, since now we can be sure that when a client sends the bundle-uri command, it is because:

1. A bundle exists
2. The server advertised the capability
3. The client support the capability

Thus, we now have a way to know if a client is using bundle-uri or not.

References: #6572 (closed)

internal/bundleuri/git_config_test.go

@@ -10,10 +10,14 @@ import (
 	"gitlab.com/gitlab-org/gitaly/v16/internal/testhelper"
 )
 
-func Test_capabilitiesGitConfig(t *testing.T) {
+func TestCapabilitiesGitConfig(t *testing.T) {
 	t.Parallel()
-	featureFlagSet := testhelper.NewFeatureSets(featureflag.BundleURI)
+	testhelper.NewFeatureSets(
+		featureflag.BundleURI,
+	).Run(t, testCapabilitiesGitConfig)
+}
 
+func testCapabilitiesGitConfig(t *testing.T, ctx context.Context) {
 	tests := []struct {
 		desc     string
 		enabled  bool
@@ -41,26 +45,29 @@ func Test_capabilitiesGitConfig(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		featureFlagSet.Run(t, func(t *testing.T, ctx context.Context) {
-			got := CapabilitiesGitConfig(ctx, tt.enabled)
-			if featureflag.BundleURI.IsEnabled(ctx) {
-				require.ElementsMatch(t, tt.expected, got)
-			} else {
-				require.ElementsMatch(t, []gitcmd.ConfigPair{
-					{
-						Key:   "uploadpack.advertiseBundleURIs",
-						Value: "false",
-					},
-				}, got)
-			}
-		})
+		got := CapabilitiesGitConfig(ctx, tt.enabled)
+		if featureflag.BundleURI.IsEnabled(ctx) {
+			require.ElementsMatch(t, tt.expected, got)
+		} else {
+			require.ElementsMatch(t, []gitcmd.ConfigPair{
+				{
+					Key:   "uploadpack.advertiseBundleURIs",
+					Value: "false",
+				},
+			}, got)
+		}
+
 	}
 }
 
-func Test_uploadPackGitConfig(t *testing.T) {
+func TestUploadPackGitConfig(t *testing.T) {
 	t.Parallel()
-	featureFlagSet := testhelper.NewFeatureSets(featureflag.BundleURI)
+	testhelper.NewFeatureSets(
+		featureflag.BundleURI,
+	).Run(t, testUploadPackGitConfig)
+}
 
+func testUploadPackGitConfig(t *testing.T, ctx context.Context) {
 	tests := []struct {
 		desc     string
 		uri      string
@@ -108,18 +115,16 @@ func Test_uploadPackGitConfig(t *testing.T) {
 		},
 	}
 	for _, tt := range tests {
-		featureFlagSet.Run(t, func(t *testing.T, ctx context.Context) {
-			got := UploadPackGitConfig(ctx, tt.uri)
-			if featureflag.BundleURI.IsEnabled(ctx) {
-				require.ElementsMatch(t, tt.expected, got)
-			} else {
-				require.ElementsMatch(t, []gitcmd.ConfigPair{
-					{
-						Key:   "uploadpack.advertiseBundleURIs",
-						Value: "false",
-					},
-				}, got)
-			}
-		})
+		got := UploadPackGitConfig(ctx, tt.uri)
+		if featureflag.BundleURI.IsEnabled(ctx) {
+			require.ElementsMatch(t, tt.expected, got)
+		} else {
+			require.ElementsMatch(t, []gitcmd.ConfigPair{
+				{
+					Key:   "uploadpack.advertiseBundleURIs",
+					Value: "false",
+				},
+			}, got)
+		}
 	}
 }