add io/signal

1 files changed, 33 insertions, 0 deletions

diff --git a/internal/io/signal/signal.go b/internal/io/signal/signal.go
new file mode 100644
index 0000000..bca7e6e
--- /dev/null
+++ b/internal/io/signal/signal.go
@@ -0,0 +1,33 @@
+package signal
+
+import (
+	"context"
+	"os"
+	gosignal "os/signal"
+	"syscall"
+)
+
+// StatsCh returns a channel for "please print stats" signalling.
+func StatsCh(ctx context.Context) <-chan struct{} {
+	sigCh := make(chan os.Signal)
+	gosignal.Notify(sigCh, syscall.SIGINFO, syscall.SIGUSR1)
+
+	statsCh := make(chan struct{})
+
+	go func() {
+		for {
+			select {
+			case <-sigCh:
+				select {
+				case statsCh <- struct{}{}:
+				default:
+					// Stats currently already printed.
+				}
+			case <-ctx.Done():
+				return
+			}
+		}
+	}()
+
+	return statsCh
+}