Bridge · From syntax to engineering · 25 MIN

Plan bounded retries

A retry policy needs both a delay limit and a total budget.

Retrying every failure can multiply traffic exactly when a service is struggling. First decide which failures are retryable and whether repeating the operation is safe. This exercise models only the schedule: double the delay, cap it, and stop before the total waiting budget is exceeded. A deterministic calculation is easy to test. A production scheduler also needs cancellation, a deadline covering request time, and jitter to avoid clients retrying together. Do not retry a payment write without a stable idempotency key.

Write a small contract first, then test how the implementation behaves at its boundaries.

Read the example

console.log(Math.min(100 * 2, 150));

150

Your challenge

Input {attempts:nonnegative integer, base:positive integer, cap:positive integer, budget:nonnegative integer}. Return up to attempts delays. Start at min(base,cap), double up to cap, and stop if adding a delay would exceed budget.

Solution cost: O(a), a emitted delays. time · O(a) for the returned schedule. space

Common trap

A cap on each delay does not limit the total time spent retrying.

Further reading: MDN AbortSignal