fix Linux tailer shutdown

tailer/fileTailer.go

@@ -143,6 +143,16 @@ func runFileTailer(path string, readall bool, failOnMissingFile bool, logger sim
 				}
 				return
 			case evnts := <-eventLoop.Events():
+				if evnts == nil {
+					select {
+					case <-done:
+						// The tailer is shutting down and closed the 'done' and 'errors' channels. This is ok.
+					default:
+						// 'done' is still open, the tailer is not shutting down. This is a bug.
+						writeError(errors, done, "failed to watch %v: unknown error", abspath)
+					}
+					return
+				}
 				var freshLines []string
 				file, freshLines, err = evnts.Process(file, reader, abspath, logger)
 				if err != nil {

tailer/fileTailer_linux.go

@@ -103,7 +103,7 @@ func (w *watcher) StartEventLoop() EventLoop {
 						event.Name = strings.TrimRight(string(bytes[0:event.Len]), "\000")
 					}
 					if event.Mask&syscall.IN_IGNORED == syscall.IN_IGNORED {
-						// eventLoop.Close() was called.
+						// eventLoop.Close() was called or log dir was deleted
 						return
 					}
 					eventsWithName = append(eventsWithName, event)

tailer/fileTailer_test.go

@@ -608,12 +608,20 @@ func runTestShutdown(t *testing.T, mode string) {
 	default:
 		t.Fatalf("Unknown mode: %v", mode)
 	}
-	_, ok := <-eventLoop.Errors()
-	if ok {
-		t.Fatalf("error channel not closed")
+	select {
+	case _, ok := <-eventLoop.Errors():
+		if ok {
+			t.Fatalf("error channel not closed")
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatalf("timeout while waiting for errors channel to be closed.")
 	}
-	_, ok = <-eventLoop.Events()
-	if ok {
-		t.Fatalf("events channel not closed")
+	select {
+	case _, ok := <-eventLoop.Events():
+		if ok {
+			t.Fatalf("events channel not closed")
+		}
+	case <-time.After(5 * time.Second):
+		t.Fatalf("timeout while waiting for errors channel to be closed.")
 	}
 }