add retry package

internal/retry/retry_test.go

@@ -0,0 +1,124 @@
+package retry_test
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+
+	"github.com/pomerium/pomerium/internal/retry"
+)
+
+func TestRetry(t *testing.T) {
+	t.Parallel()
+
+	ctx := context.Background()
+	limit := retry.WithMaxInterval(time.Second * 5)
+
+	t.Run("no error", func(t *testing.T) {
+		t.Parallel()
+
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			return nil
+		}, limit)
+		require.NoError(t, err)
+	})
+
+	t.Run("eventually succeeds", func(t *testing.T) {
+		t.Parallel()
+		i := 0
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			if i++; i > 2 {
+				return nil
+			}
+			return fmt.Errorf("transient %d", i)
+		}, limit)
+		require.NoError(t, err)
+	})
+
+	t.Run("eventually fails", func(t *testing.T) {
+		t.Parallel()
+		i := 0
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			if i++; i > 2 {
+				return retry.NewTerminalError(errors.New("the end"))
+			}
+			return fmt.Errorf("transient %d", i)
+		})
+		require.Error(t, err)
+	})
+
+	t.Run("context canceled", func(t *testing.T) {
+		t.Parallel()
+		ctx, cancel := context.WithCancel(ctx)
+		cancel()
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			return fmt.Errorf("retry")
+		})
+		require.Error(t, err)
+	})
+
+	t.Run("context canceled after retry", func(t *testing.T) {
+		t.Parallel()
+		ctx, cancel := context.WithCancel(ctx)
+		t.Cleanup(cancel)
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			cancel()
+			return fmt.Errorf("retry")
+		})
+		require.Error(t, err)
+	})
+
+	t.Run("success after watch hook", func(t *testing.T) {
+		t.Parallel()
+		ch := make(chan struct{}, 1)
+		ch <- struct{}{}
+		ok := false
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			if ok {
+				return nil
+			}
+			return fmt.Errorf("retry")
+		}, retry.WithWatch("watch", ch, func(_ context.Context) error {
+			ok = true
+			return nil
+		}), limit)
+		require.NoError(t, err)
+	})
+
+	t.Run("success after watch hook retried", func(t *testing.T) {
+		t.Parallel()
+		ch := make(chan struct{}, 1)
+		ch <- struct{}{}
+		ok := false
+		i := 0
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			if ok {
+				return nil
+			}
+			return fmt.Errorf("retry test")
+		}, retry.WithWatch("watch", ch, func(_ context.Context) error {
+			if i++; i > 1 {
+				ok = true
+				return nil
+			}
+			return fmt.Errorf("retry watch")
+		}), limit)
+		require.NoError(t, err)
+	})
+
+	t.Run("watch hook fails", func(t *testing.T) {
+		t.Parallel()
+		ch := make(chan struct{}, 1)
+		ch <- struct{}{}
+		err := retry.Retry(ctx, "test", func(_ context.Context) error {
+			return fmt.Errorf("retry")
+		}, retry.WithWatch("watch", ch, func(_ context.Context) error {
+			return retry.NewTerminalError(fmt.Errorf("watch"))
+		}), limit)
+		require.Error(t, err)
+	})
+}