fileutil: rework purge tests so they don't poll

Fixes #5966

pkg/fileutil/purge.go

@@ -23,6 +23,11 @@ import (
 )
 
 func PurgeFile(dirname string, suffix string, max uint, interval time.Duration, stop <-chan struct{}) <-chan error {
+	return purgeFile(dirname, suffix, max, interval, stop, nil)
+}
+
+// purgeFile is the internal implementation for PurgeFile which can post purged files to purgec if non-nil.
+func purgeFile(dirname string, suffix string, max uint, interval time.Duration, stop <-chan struct{}, purgec chan<- string) <-chan error {
 	errC := make(chan error, 1)
 	go func() {
 		for {
@@ -38,6 +43,7 @@ func PurgeFile(dirname string, suffix string, max uint, interval time.Duration,
 				}
 			}
 			sort.Strings(newfnames)
+			fnames = newfnames
 			for len(newfnames) > int(max) {
 				f := path.Join(dirname, newfnames[0])
 				l, err := TryLockFile(f, os.O_WRONLY, PrivateFileMode)
@@ -56,6 +62,11 @@ func PurgeFile(dirname string, suffix string, max uint, interval time.Duration,
 				plog.Infof("purged file %s successfully", f)
 				newfnames = newfnames[1:]
 			}
+			if purgec != nil {
+				for i := 0; i < len(fnames)-len(newfnames); i++ {
+					purgec <- fnames[i]
+				}
+			}
 			select {
 			case <-time.After(interval):
 			case <-stop:

pkg/fileutil/purge_test.go

@@ -31,44 +31,48 @@ func TestPurgeFile(t *testing.T) {
 	}
 	defer os.RemoveAll(dir)
 
-	for i := 0; i < 5; i++ {
+	// minimal file set
-		var f *os.File
+	for i := 0; i < 3; i++ {
-		f, err = os.Create(path.Join(dir, fmt.Sprintf("%d.test", i)))
+		f, ferr := os.Create(path.Join(dir, fmt.Sprintf("%d.test", i)))
-		if err != nil {
+		if ferr != nil {
 			t.Fatal(err)
 		}
 		f.Close()
 	}
 
-	stop := make(chan struct{})
+	stop, purgec := make(chan struct{}), make(chan string, 10)
 
-	// keep at most 3 most recent files
+	// keep 3 most recent files
-	errch := PurgeFile(dir, "test", 3, time.Millisecond, stop)
+	errch := purgeFile(dir, "test", 3, time.Millisecond, stop, purgec)
-
+	select {
-	// create 5 more files
+	case f := <-purgec:
-	for i := 5; i < 10; i++ {
+		t.Errorf("unexpected purge on %q", f)
-		var f *os.File
+	case <-time.After(10 * time.Millisecond):
-		f, err = os.Create(path.Join(dir, fmt.Sprintf("%d.test", i)))
-		if err != nil {
-			t.Fatal(err)
-		}
-		f.Close()
-		time.Sleep(10 * time.Millisecond)
 	}
 
-	// purge routine should purge 7 out of 10 files and only keep the
+	// rest of the files
-	// 3 most recent ones.
+	for i := 4; i < 10; i++ {
-	// Wait for purging for at most 300ms.
+		go func(n int) {
-	var fnames []string
+			f, ferr := os.Create(path.Join(dir, fmt.Sprintf("%d.test", n)))
-	for i := 0; i < 30; i++ {
+			if ferr != nil {
-		fnames, err = ReadDir(dir)
+				t.Fatal(err)
-		if err != nil {
+			}
-			t.Fatal(err)
+			f.Close()
+		}(i)
+	}
+
+	// watch files purge away
+	for i := 4; i < 10; i++ {
+		select {
+		case <-purgec:
+		case <-time.After(time.Second):
+			t.Errorf("purge took too long")
 		}
-		if len(fnames) <= 3 {
+	}
-			break
+
-		}
+	fnames, rerr := ReadDir(dir)
-		time.Sleep(10 * time.Millisecond)
+	if rerr != nil {
+		t.Fatal(rerr)
 	}
 	wnames := []string{"7.test", "8.test", "9.test"}
 	if !reflect.DeepEqual(fnames, wnames) {
@@ -77,9 +81,11 @@ func TestPurgeFile(t *testing.T) {
 
 	// no error should be reported from purge routine
 	select {
+	case f := <-purgec:
+		t.Errorf("unexpected purge on %q", f)
 	case err := <-errch:
 		t.Errorf("unexpected purge error %v", err)
-	case <-time.After(time.Millisecond):
+	case <-time.After(10 * time.Millisecond):
 	}
 	close(stop)
 }
@@ -107,29 +113,33 @@ func TestPurgeFileHoldingLockFile(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	stop := make(chan struct{})
+	stop, purgec := make(chan struct{}), make(chan string, 10)
-	errch := PurgeFile(dir, "test", 3, time.Millisecond, stop)
+	errch := purgeFile(dir, "test", 3, time.Millisecond, stop, purgec)
 
-	var fnames []string
+	for i := 0; i < 5; i++ {
-	for i := 0; i < 10; i++ {
+		select {
-		fnames, err = ReadDir(dir)
+		case <-purgec:
-		if err != nil {
+		case <-time.After(time.Second):
-			t.Fatal(err)
+			t.Fatalf("purge took too long")
 		}
-		if len(fnames) <= 5 {
-			break
-		}
-		time.Sleep(10 * time.Millisecond)
 	}
+
+	fnames, rerr := ReadDir(dir)
+	if rerr != nil {
+		t.Fatal(rerr)
+	}
+
 	wnames := []string{"5.test", "6.test", "7.test", "8.test", "9.test"}
 	if !reflect.DeepEqual(fnames, wnames) {
 		t.Errorf("filenames = %v, want %v", fnames, wnames)
 	}
 
 	select {
+	case s := <-purgec:
+		t.Errorf("unexpected purge %q", s)
 	case err = <-errch:
 		t.Errorf("unexpected purge error %v", err)
-	case <-time.After(time.Millisecond):
+	case <-time.After(10 * time.Millisecond):
 	}
 
 	// remove the purge barrier
@@ -137,15 +147,18 @@ func TestPurgeFileHoldingLockFile(t *testing.T) {
 		t.Fatal(err)
 	}
 
-	for i := 0; i < 10; i++ {
+	// wait for rest of purges (5, 6)
-		fnames, err = ReadDir(dir)
+	for i := 0; i < 2; i++ {
-		if err != nil {
+		select {
-			t.Fatal(err)
+		case <-purgec:
+		case <-time.After(time.Second):
+			t.Fatalf("purge took too long")
 		}
-		if len(fnames) <= 3 {
+	}
-			break
+
-		}
+	fnames, rerr = ReadDir(dir)
-		time.Sleep(10 * time.Millisecond)
+	if rerr != nil {
+		t.Fatal(rerr)
 	}
 	wnames = []string{"7.test", "8.test", "9.test"}
 	if !reflect.DeepEqual(fnames, wnames) {
@@ -153,9 +166,11 @@ func TestPurgeFileHoldingLockFile(t *testing.T) {
 	}
 
 	select {
+	case f := <-purgec:
+		t.Errorf("unexpected purge on %q", f)
 	case err := <-errch:
 		t.Errorf("unexpected purge error %v", err)
-	case <-time.After(time.Millisecond):
+	case <-time.After(10 * time.Millisecond):
 	}
 
 	close(stop)