refactor: replace doRevalFn closure with direct filter reference in revalJob

Replace the func() closure field on revalJob with a *cacheFilter pointer
and call job.filter.doRevalidate(job.key, job.req) directly in the worker.
The closure was only binding key and req, which revalJob already carries as
fields, making the indirection unnecessary.

Also fixes two missing spec.Close() calls in TestCreateFilter_InvalidArgs and
TestCacheFilter_SharedStorage_RouteIsolation that caused goroutine leaks.

Signed-off-by: larry-dalmeida <hello@larrydalmeida.com>

Author: larry-dalmeida

filters/cache/filter.go

@@ -202,12 +202,12 @@ func (s *cacheSpec) CreateFilter(args []interface{}) (filters.Filter, error) {
 
 // revalidationWorker is the single background goroutine (spec-level, shared across
 // all filter instances) that processes revalidation jobs sequentially. It calls
-// the per-instance doRevalidateFn closure to respect each route's configuration.
+// the per-instance doRevalidate method to respect each route's configuration.
 func (s *cacheSpec) revalidationWorker() {
 	defer s.bgWg.Done()
 	for job := range s.revalJobs {
-		if job.doRevalFn != nil {
-			job.doRevalFn()
+		if job.filter != nil {
+			job.filter.doRevalidate(job.key, job.req)
 		}
 	}
 	log.Debug("cache: revalidation worker stopped")
@@ -233,9 +233,9 @@ func (s *cacheSpec) lruBytesScraper() {
 }
 
 type revalJob struct {
-	key       string
-	req       *http.Request // pre-cloned, safe to use after the originating request ends
-	doRevalFn func()        // closure with access to per-instance doRevalidate
+	key    string
+	req    *http.Request // pre-cloned, safe to use after the originating request ends
+	filter *cacheFilter  // instance whose doRevalidate to call
 }
 
 type cacheFilter struct {
@@ -704,11 +704,9 @@ func (f *cacheFilter) Response(ctx filters.FilterContext) {
 func (f *cacheFilter) enqueueRevalidation(key string, orig *http.Request) {
 	cloned := orig.Clone(context.Background())
 	job := revalJob{
-		key: key,
-		req: cloned,
-		doRevalFn: func() {
-			f.doRevalidate(key, cloned)
-		},
+		key:    key,
+		req:    cloned,
+		filter: f,
 	}
 	select {
 	case f.revalJobs <- job:

filters/cache/filter_test.go

@@ -140,6 +140,7 @@ func TestCacheFilter_KeyIsolationByAuthToken(t *testing.T) {
 	f := fi.(*cacheFilter)
 	t.Cleanup(f.Close)
 	t.Cleanup(spec.(*cacheSpec).client.Close)
+	t.Cleanup(spec.(*cacheSpec).Close)
 	f.fetch = func(*http.Request) (*http.Response, error) {
 		return nil, errors.New("no fetch stub set")
 	}
@@ -264,6 +265,7 @@ func TestCacheFilter_Response_NoopIfStateBagKeyMissing(t *testing.T) {
 func TestCreateFilter_InvalidArgs(t *testing.T) {
 	spec := NewCacheFilter(Options{MaxBytes: 1 << 20, ListenAddr: "localhost:9090", L1TTL: 60 * time.Second})
 	t.Cleanup(spec.(*cacheSpec).client.Close)
+	t.Cleanup(spec.(*cacheSpec).Close)
 	cases := []struct {
 		name string
 		args []interface{}
@@ -1319,6 +1321,7 @@ func TestCacheFilter_MustRevalidate_ForcesCoalesceWhenStale(t *testing.T) {
 func TestCacheFilter_SharedStorage_RouteIsolation(t *testing.T) {
 	spec := NewCacheFilter(Options{MaxBytes: 1 << 20, ListenAddr: "localhost:9090", L1TTL: 60 * time.Second})
 	t.Cleanup(spec.(*cacheSpec).client.Close)
+	t.Cleanup(spec.(*cacheSpec).Close)
 
 	makeFilter := func(t *testing.T) *cacheFilter {
 		t.Helper()
@@ -2804,9 +2807,9 @@ func TestCacheFilter_RevalDropped_WhenQueueFull(t *testing.T) {
 		return nil, errors.New("blocked fetch")
 	}
 
-	// Send one dummy job so the worker goroutine wakes and blocks inside fetch.
+	// Send one job so the worker goroutine wakes and blocks inside fetch.
 	dummyReq, _ := http.NewRequest(http.MethodGet, "http://example.com/dummy", nil)
-	f.revalJobs <- revalJob{key: "dummy-wake", req: dummyReq}
+	f.revalJobs <- revalJob{key: "dummy-wake", req: dummyReq, filter: f}
 
 	// Wait for the worker to confirm it is inside fetch — no timing guesswork.
 	<-workerIn