internal/xdscache: Generate uuid for snapshot version (#5819)

Snapshotter had a data race reading/writing the snapshot version between threads. This version is not in practice used for the contour xDS server DiscoveryResponse versions but is in the go-control-plane version. Fixes: #5482 Signed-off-by: Sunjay Bhatia <[email protected]>
projectcontour · Oct 10, 2023 · 8f6aff1 · 8f6aff1
1 parent 2765c72
commit 8f6aff1
Show file tree

Hide file tree

Showing 3 changed files with 3 additions and 78 deletions.
diff --git a/go.mod b/go.mod
@@ -15,6 +15,7 @@ require (
 	github.com/go-logr/logr v1.2.4
 	github.com/google/go-cmp v0.5.9
 	github.com/google/go-github/v48 v48.2.0
+	github.com/google/uuid v1.3.1
 	github.com/grpc-ecosystem/go-grpc-middleware v1.4.0
 	github.com/grpc-ecosystem/go-grpc-prometheus v1.2.0
 	github.com/onsi/ginkgo/v2 v2.12.1
@@ -79,7 +80,6 @@ require (
 	github.com/google/go-querystring v1.1.0 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 // indirect
-	github.com/google/uuid v1.3.1 // indirect
 	github.com/hashicorp/hcl v1.0.1-vault-5 // indirect
 	github.com/huandu/xstrings v1.4.0 // indirect
 	github.com/iancoleman/strcase v0.2.0 // indirect

diff --git a/internal/xdscache/snapshot.go b/internal/xdscache/snapshot.go
@@ -14,13 +14,12 @@
 package xdscache
 
 import (
-	"math"
 	"reflect"
-	"strconv"
 	"sync"
 
 	envoy_types "github.com/envoyproxy/go-control-plane/pkg/cache/types"
 	envoy_resource_v3 "github.com/envoyproxy/go-control-plane/pkg/resource/v3"
+	"github.com/google/uuid"
 	"github.com/projectcontour/contour/internal/dag"
 	"github.com/sirupsen/logrus"
 )
@@ -36,9 +35,6 @@ type SnapshotHandler struct {
 	// resources holds the cache of xDS contents.
 	resources map[envoy_resource_v3.Type]ResourceCache
 
-	// snapshotVersion holds the current version of the snapshot.
-	snapshotVersion int64
-
 	snapshotters []Snapshotter
 	snapLock     sync.Mutex
 
@@ -75,7 +71,7 @@ func (s *SnapshotHandler) OnChange(root *dag.DAG) {
 // the Contour XDS caches.
 func (s *SnapshotHandler) generateNewSnapshot() {
 	// Generate new snapshot version.
-	version := s.newSnapshotVersion()
+	version := uuid.NewString()
 
 	// Convert caches to envoy xDS Resources.
 	resources := map[envoy_resource_v3.Type][]envoy_types.Resource{
@@ -97,20 +93,6 @@ func (s *SnapshotHandler) generateNewSnapshot() {
 	}
 }
 
-// newSnapshotVersion increments the current snapshotVersion
-// and returns as a string.
-func (s *SnapshotHandler) newSnapshotVersion() string {
-
-	// Reset the snapshotVersion if it ever hits max size.
-	if s.snapshotVersion == math.MaxInt64 {
-		s.snapshotVersion = 0
-	}
-
-	// Increment the snapshot version & return as string.
-	s.snapshotVersion++
-	return strconv.FormatInt(s.snapshotVersion, 10)
-}
-
 // asResources casts the given slice of values (that implement the envoy_types.Resource
 // interface) to a slice of envoy_types.Resource. If the length of the slice is 0, it
 // returns nil.

diff --git a/internal/xdscache/snapshot_test.go b/internal/xdscache/snapshot_test.go