add generic retry supervisor

internal/playback/supervisor.go

@@ -0,0 +1,54 @@
+package playback
+
+import (
+	"context"
+	"time"
+)
+
+type attemptFunc func(context.Context) error
+type retryDecider func(error) bool
+type waitFunc func(context.Context, time.Duration) error
+
+func waitForRetry(ctx context.Context, delay time.Duration) error {
+	timer := time.NewTimer(delay)
+	defer timer.Stop()
+
+	select {
+	case <-timer.C:
+		return nil
+	case <-ctx.Done():
+		return ctx.Err()
+	}
+}
+
+func runWithRetry(
+	ctx context.Context,
+	policy RetryPolicy,
+	attempt attemptFunc,
+	shouldRetry retryDecider,
+	wait waitFunc,
+) error {
+	failedAttempts := 0
+
+	for {
+		err := attempt(ctx)
+		if err == nil {
+			return nil
+		}
+		if ctx.Err() != nil {
+			return ctx.Err()
+		}
+
+		failedAttempts++
+		if !shouldRetry(err) || !policy.canRetry(failedAttempts) {
+			return err
+		}
+
+		if err := wait(ctx, policy.retryDelay(failedAttempts)); err != nil {
+			if ctx.Err() != nil {
+				return ctx.Err()
+			}
+			return err
+		}
+	}
+}

internal/playback/supervisor_test.go

@@ -0,0 +1,230 @@
+package playback
+
+import (
+	"context"
+	"errors"
+	"reflect"
+	"testing"
+	"time"
+)
+
+func testRetryPolicy(maxAttempts int) RetryPolicy {
+	return RetryPolicy{
+		MaxAttempts:  maxAttempts,
+		InitialDelay: 500 * time.Millisecond,
+		MaxDelay:     10 * time.Second,
+	}
+}
+
+func TestRunWithRetryFirstAttemptSucceeds(t *testing.T) {
+	attempts := 0
+	err := runWithRetry(
+		context.Background(),
+		testRetryPolicy(3),
+		func(context.Context) error {
+			attempts++
+			return nil
+		},
+		func(error) bool {
+			t.Fatal("shouldRetry called after successful attempt")
+			return false
+		},
+		func(context.Context, time.Duration) error {
+			t.Fatal("wait called after successful attempt")
+			return nil
+		},
+	)
+
+	if err != nil {
+		t.Fatalf("runWithRetry() error = %v, want nil", err)
+	}
+	if attempts != 1 {
+		t.Fatalf("attempt count = %d, want 1", attempts)
+	}
+}
+
+func TestRunWithRetryFailuresThenSuccess(t *testing.T) {
+	attemptErr := errors.New("attempt failed")
+	attempts := 0
+	var delays []time.Duration
+
+	err := runWithRetry(
+		context.Background(),
+		testRetryPolicy(3),
+		func(context.Context) error {
+			attempts++
+			if attempts < 3 {
+				return attemptErr
+			}
+			return nil
+		},
+		func(error) bool { return true },
+		func(_ context.Context, delay time.Duration) error {
+			delays = append(delays, delay)
+			return nil
+		},
+	)
+
+	if err != nil {
+		t.Fatalf("runWithRetry() error = %v, want nil", err)
+	}
+	if attempts != 3 {
+		t.Errorf("attempt count = %d, want 3", attempts)
+	}
+	wantDelays := []time.Duration{500 * time.Millisecond, time.Second}
+	if !reflect.DeepEqual(delays, wantDelays) {
+		t.Errorf("retry delays = %v, want %v", delays, wantDelays)
+	}
+}
+
+func TestRunWithRetryFiniteAttemptsExhausted(t *testing.T) {
+	attemptErr := errors.New("attempt failed")
+	attempts := 0
+	waits := 0
+
+	err := runWithRetry(
+		context.Background(),
+		testRetryPolicy(3),
+		func(context.Context) error {
+			attempts++
+			return attemptErr
+		},
+		func(error) bool { return true },
+		func(context.Context, time.Duration) error {
+			waits++
+			return nil
+		},
+	)
+
+	if !errors.Is(err, attemptErr) {
+		t.Fatalf("runWithRetry() error = %v, want %v", err, attemptErr)
+	}
+	if attempts != 3 {
+		t.Errorf("attempt count = %d, want 3", attempts)
+	}
+	if waits != 2 {
+		t.Errorf("wait count = %d, want 2", waits)
+	}
+}
+
+func TestRunWithRetryUnlimitedEventuallySucceeds(t *testing.T) {
+	attemptErr := errors.New("attempt failed")
+	attempts := 0
+
+	err := runWithRetry(
+		context.Background(),
+		testRetryPolicy(0),
+		func(context.Context) error {
+			attempts++
+			if attempts < 20 {
+				return attemptErr
+			}
+			return nil
+		},
+		func(error) bool { return true },
+		func(context.Context, time.Duration) error { return nil },
+	)
+
+	if err != nil {
+		t.Fatalf("runWithRetry() error = %v, want nil", err)
+	}
+	if attempts != 20 {
+		t.Fatalf("attempt count = %d, want 20", attempts)
+	}
+}
+
+func TestRunWithRetryStopsWhenErrorIsNotRetryable(t *testing.T) {
+	attemptErr := errors.New("invalid configuration")
+	attempts := 0
+
+	err := runWithRetry(
+		context.Background(),
+		testRetryPolicy(0),
+		func(context.Context) error {
+			attempts++
+			return attemptErr
+		},
+		func(error) bool { return false },
+		func(context.Context, time.Duration) error {
+			t.Fatal("wait called for non-retryable error")
+			return nil
+		},
+	)
+
+	if !errors.Is(err, attemptErr) {
+		t.Fatalf("runWithRetry() error = %v, want %v", err, attemptErr)
+	}
+	if attempts != 1 {
+		t.Fatalf("attempt count = %d, want 1", attempts)
+	}
+}
+
+func TestRunWithRetryReturnsCancellationFromAttempt(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	attemptErr := errors.New("attempt failed")
+
+	err := runWithRetry(
+		ctx,
+		testRetryPolicy(0),
+		func(context.Context) error {
+			cancel()
+			return attemptErr
+		},
+		func(error) bool { return true },
+		func(context.Context, time.Duration) error {
+			t.Fatal("wait called after cancellation")
+			return nil
+		},
+	)
+
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("runWithRetry() error = %v, want context.Canceled", err)
+	}
+}
+
+func TestRunWithRetryReturnsCancellationDuringBackoff(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	attemptErr := errors.New("attempt failed")
+
+	err := runWithRetry(
+		ctx,
+		testRetryPolicy(0),
+		func(context.Context) error { return attemptErr },
+		func(error) bool { return true },
+		func(ctx context.Context, _ time.Duration) error {
+			cancel()
+			return ctx.Err()
+		},
+	)
+
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("runWithRetry() error = %v, want context.Canceled", err)
+	}
+}
+
+func TestRunWithRetryReturnsWaitError(t *testing.T) {
+	attemptErr := errors.New("attempt failed")
+	waitErr := errors.New("wait failed")
+
+	err := runWithRetry(
+		context.Background(),
+		testRetryPolicy(0),
+		func(context.Context) error { return attemptErr },
+		func(error) bool { return true },
+		func(context.Context, time.Duration) error { return waitErr },
+	)
+
+	if !errors.Is(err, waitErr) {
+		t.Fatalf("runWithRetry() error = %v, want %v", err, waitErr)
+	}
+}
+
+func TestWaitForRetryReturnsCancellation(t *testing.T) {
+	ctx, cancel := context.WithCancel(context.Background())
+	cancel()
+
+	err := waitForRetry(ctx, time.Hour)
+	if !errors.Is(err, context.Canceled) {
+		t.Fatalf("waitForRetry() error = %v, want context.Canceled", err)
+	}
+}