add a lock for safety (#467)

slackhq · Jul 30, 2024 · 2fc9c78 · 2fc9c78
1 parent e08ecae
commit 2fc9c78
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/go/vt/vtgateproxy/discovery.go b/go/vt/vtgateproxy/discovery.go
@@ -66,6 +66,7 @@ type JSONGateResolver struct {
  clientConn resolver.ClientConn
  poolType string
  currentAddrs []resolver.Address
+ mu sync.Mutex
 }
 
 func (r *JSONGateResolver) ResolveNow(o resolver.ResolveNowOptions) {}
@@ -398,6 +399,11 @@ func (b *JSONGateResolverBuilder) update(r *JSONGateResolver) error {
 
  targets := b.getTargets(r.poolType)
 
+ // There should only ever be a single goroutine calling update on a given Resolver,
+ // but add a lock just in case to ensure that the r.currentAddrs are in fact synchronized
+ r.mu.Lock()
+ defer r.mu.Unlock()
+
  var addrs []resolver.Address
  for _, target := range targets {
  addrs = append(addrs, resolver.Address{Addr: target.Addr, Attributes: attributes.New(PoolTypeAttr, r.poolType)})