Function Retry

cel/async/async.go:174–222

Retry wraps a BlockingAsyncOp with a retry policy. It will retry the operation if it returns a types.Err that wraps a RetryableError returning true for IsRetryable.

(fn functions.BlockingAsyncOp, opts ...RetryOption)

// Retry wraps a BlockingAsyncOp with a retry policy.
// It will retry the operation if it returns a types.Err that wraps a RetryableError returning true for IsRetryable.
func Retry(fn functions.BlockingAsyncOp, opts ...RetryOption) functions.BlockingAsyncOp {
	config := &retryConfig{
		maxAttempts: 3,
		backoff:     100 * time.Millisecond,
	}
	for _, opt := range opts {
		opt(config)
	}

	return func(ctx context.Context, args ...ref.Val) ref.Val {
		var lastErr ref.Val
		var backoff *time.Timer
		defer func() {
			if backoff != nil {
				backoff.Stop()
			}
		}()
		for i := 0; i < config.maxAttempts; i++ {
			if i > 0 {
				// Reuse a single timer across attempts and stop it on cancellation so the
				// pending timer is not left to fire after the call returns.
				if backoff == nil {
					backoff = time.NewTimer(config.backoff)
				} else {
					backoff.Reset(config.backoff)
				}
				select {
				case <-backoff.C:
				case <-ctx.Done():
					backoff.Stop()
					return types.NewErr("operation cancelled during retry: %v", ctx.Err())
				}
			}

			res := fn(ctx, args...)
			if !types.IsError(res) {
				return res
			}

			err := res.(*types.Err)
			lastErr = res

			if !isRetryable(err) {
				return res
			}
		}
		return lastErr
	}
}

// RetryBinding wraps a BlockingAsyncOp with a retry policy and returns an OverloadOpt.
func RetryBinding(fn functions.BlockingAsyncOp, opts ...RetryOption) decls.OverloadOpt {