First commit Go counter service

internal/watcher/watcher_test.go

@@ -0,0 +1,189 @@
+package watcher
+
+import (
+	"errors"
+	"os"
+	"path/filepath"
+	"sync/atomic"
+	"testing"
+	"time"
+)
+
+func write(t *testing.T, path, content string) {
+	t.Helper()
+	if err := os.WriteFile(path, []byte(content), 0o644); err != nil {
+		t.Fatal(err)
+	}
+}
+
+// replace mimics the agent's atomic deploy: write a temp file next to the
+// target and rename it over the target.
+func replace(t *testing.T, path, content string) {
+	t.Helper()
+	tmp := path + ".tmp"
+	write(t, tmp, content)
+	if err := os.Rename(tmp, path); err != nil {
+		t.Fatal(err)
+	}
+}
+
+type counter struct {
+	n    atomic.Int32
+	done chan struct{}
+	err  error
+}
+
+func newCounter() *counter { return &counter{done: make(chan struct{}, 16)} }
+
+func (c *counter) reload() error {
+	c.n.Add(1)
+	select {
+	case c.done <- struct{}{}:
+	default:
+	}
+	return c.err
+}
+
+func (c *counter) wait(t *testing.T) {
+	t.Helper()
+	select {
+	case <-c.done:
+	case <-time.After(5 * time.Second):
+		t.Fatal("timeout waiting for reload")
+	}
+}
+
+// start creates and starts a watcher; debounce must be set before Start so
+// the watcher goroutine never races with the test.
+func start(t *testing.T, path string, c *counter, debounce time.Duration) *Watcher {
+	t.Helper()
+	w, err := New([]string{path}, c.reload)
+	if err != nil {
+		t.Fatal(err)
+	}
+	w.debounce = debounce
+	w.Start()
+	t.Cleanup(w.Stop)
+	time.Sleep(50 * time.Millisecond) // let the watches settle
+	return w
+}
+
+func TestWatcher_ReloadsOnInPlaceWrite(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "rspamd_domains_db")
+	write(t, path, "v1")
+	c := newCounter()
+	start(t, path, c, 100*time.Millisecond)
+
+	write(t, path, "v2")
+	c.wait(t)
+	if c.n.Load() < 1 {
+		t.Errorf("reloads = %d, want >= 1", c.n.Load())
+	}
+}
+
+// The agent deploys the CDB with mv; after the first replacement the old
+// kqueue file watch is stale, so a second replacement must still be seen.
+func TestWatcher_ReloadsOnAtomicReplaceTwice(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "rspamd_domains_db")
+	write(t, path, "v1")
+	c := newCounter()
+	start(t, path, c, 100*time.Millisecond)
+
+	replace(t, path, "v2")
+	c.wait(t)
+	first := c.n.Load()
+
+	time.Sleep(150 * time.Millisecond)
+	replace(t, path, "v3")
+	c.wait(t)
+	if c.n.Load() <= first {
+		t.Errorf("second replacement not detected: reloads %d -> %d", first, c.n.Load())
+	}
+}
+
+func TestWatcher_IgnoresOtherFilesInDir(t *testing.T) {
+	dir := t.TempDir()
+	path := filepath.Join(dir, "rspamd_domains_db")
+	write(t, path, "v1")
+	c := newCounter()
+	start(t, path, c, 100*time.Millisecond)
+
+	write(t, filepath.Join(dir, "other_file"), "x")
+	time.Sleep(400 * time.Millisecond)
+	if c.n.Load() != 0 {
+		t.Errorf("reloads = %d for an unrelated file, want 0", c.n.Load())
+	}
+}
+
+func TestWatcher_DebouncesBurst(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "rspamd_domains_db")
+	write(t, path, "v1")
+	c := newCounter()
+	start(t, path, c, 200*time.Millisecond)
+
+	for i := 0; i < 5; i++ {
+		write(t, path, "burst")
+		time.Sleep(20 * time.Millisecond)
+	}
+	c.wait(t)
+	time.Sleep(500 * time.Millisecond)
+	if n := c.n.Load(); n > 2 {
+		t.Errorf("reloads = %d, want 1-2 (debounced)", n)
+	}
+}
+
+func TestWatcher_ContinuesAfterReloadError(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "rspamd_domains_db")
+	write(t, path, "v1")
+	c := newCounter()
+	c.err = errors.New("boom")
+	start(t, path, c, 100*time.Millisecond)
+
+	write(t, path, "v2")
+	c.wait(t)
+	time.Sleep(150 * time.Millisecond)
+	write(t, path, "v3")
+	c.wait(t)
+	if c.n.Load() < 2 {
+		t.Errorf("reloads = %d, want >= 2 (a failing reload must not stop the watcher)", c.n.Load())
+	}
+}
+
+func TestWatcher_StopPreventsReload(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "rspamd_domains_db")
+	write(t, path, "v1")
+	c := newCounter()
+	w := start(t, path, c, 100*time.Millisecond)
+	w.Stop()
+
+	write(t, path, "v2")
+	time.Sleep(400 * time.Millisecond)
+	if c.n.Load() != 0 {
+		t.Errorf("reloads = %d after Stop, want 0", c.n.Load())
+	}
+	w.Stop() // idempotent
+}
+
+func TestNew_MissingDirectory(t *testing.T) {
+	if _, err := New([]string{"/nonexistent-dir-for-test/rspamd_domains_db"}, func() error { return nil }); err == nil {
+		t.Fatal("expected error for a missing directory")
+	}
+}
+
+func TestNew_MissingFileInExistingDirIsFine(t *testing.T) {
+	// The CDB may be deployed after the daemon starts; the directory watch
+	// picks up its creation.
+	path := filepath.Join(t.TempDir(), "rspamd_domains_db")
+	c := newCounter()
+	w, err := New([]string{path}, c.reload)
+	if err != nil {
+		t.Fatal(err)
+	}
+	w.debounce = 100 * time.Millisecond
+	w.Start()
+	defer w.Stop()
+	time.Sleep(50 * time.Millisecond)
+
+	write(t, path, "v1")
+	c.wait(t)
+}