# `ExResilience.Retry`
[🔗](https://github.com/joshrotenberg/ex_resilience/blob/v0.4.0/lib/ex_resilience/retry.ex#L1)

Retry logic with configurable backoff strategies.

Wraps a function call and retries on failure according to the configured
strategy. Does not use a GenServer -- retry is stateless per-call.

## Options

  * `:name` -- optional atom used in telemetry metadata. Default `:retry`.
  * `:max_attempts` -- total attempts (including the first). Default `3`.
  * `:backoff` -- backoff strategy (`:fixed`, `:linear`, `:exponential`). Default `:exponential`.
  * `:base_delay` -- base delay in ms. Default `100`.
  * `:max_delay` -- cap on delay in ms. Default `10_000`.
  * `:jitter` -- jitter setting. Can be `true` (full jitter, delay randomized
    in `[0, delay]`), `false` (no jitter), or a float between 0.0 and 1.0
    for proportional jitter (delay adjusted by +/- `delay * fraction`).
    Default `true`.
  * `:retry_on` -- 1-arity predicate that returns `true` if the result
    should be retried. Default: retries `{:error, _}` and `:error`.
    Takes precedence over `:error_classifier` when both are provided.
  * `:error_classifier` -- module implementing `ExResilience.ErrorClassifier`.
    When provided (and `:retry_on` is not), retries results classified as
    `:retriable`. Ignored if `:retry_on` is also set.

## Examples

    iex> ExResilience.Retry.call(fn -> {:ok, 42} end, max_attempts: 3)
    {:ok, 42}

    iex> ExResilience.Retry.call(fn -> {:error, :fail} end, max_attempts: 2)
    {:error, :fail}

# `option`

```elixir
@type option() ::
  {:name, atom()}
  | {:max_attempts, pos_integer()}
  | {:backoff, ExResilience.Backoff.strategy()}
  | {:base_delay, ExResilience.Backoff.milliseconds()}
  | {:max_delay, ExResilience.Backoff.milliseconds()}
  | {:jitter, boolean() | float()}
  | {:retry_on, (term() -> boolean())}
  | {:error_classifier, module()}
```

# `call`

```elixir
@spec call((-> term()), [option()]) :: term()
```

Executes `fun` with retry logic.

Returns the result of the first successful call, or the last result
after all attempts are exhausted.

---

*Consult [api-reference.md](api-reference.md) for complete listing*