Dowser.
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Generic retry policy for transient HTTP failures.
Lives outside Dowser.Client.HTTP.* deliberately: retry is orchestration
around whichever adapter is configured, not a transport concern, so it
works uniformly for :httpc, Req, :hackney and any custom adapter.
resolve/1 turns opts[:retry] into a full config (stored on
%Dowser.Client.Request{}); run/2 drives an arbitrary zero-arity fun
through that policy, sleeping between attempts with exponential
full-jitter backoff; transient?/1 classifies an adapter's raw
{:error, reason} payload.
Options
opts[:retry] accepts:
false— disables retries (max_attempts: 1).- a keyword list — merged over the defaults, so a partial override (e.g.
retry: [max_attempts: 5]) only changes the given keys::max_attempts— total attempts, including the first (default3).:base_delay_ms/:max_delay_ms— exponential full-jitter backoff bounds (default200/2_000).:retryable_statuses— response statuses treated as transient (default[429, 502, 503, 504]).
Summary
Functions
Resolves opts[:retry] into a full retry config.
Runs fun up to config[:max_attempts] times, retrying as long as the
result is transient (a retryable HTTP status or a transient transport
error) and attempts remain, sleeping with jittered backoff in between.
Whether an adapter's raw {:error, reason} payload looks transient.
Types
@type config() :: keyword()
Functions
@spec resolve(keyword()) :: {:ok, config()} | {:error, Dowser.Client.Error.t()}
Resolves opts[:retry] into a full retry config.
Returns {:ok, config} or {:error, %Dowser.Client.Error{}} when
opts[:retry] is neither false nor a keyword list.
@spec run(config(), (-> term())) :: {term(), pos_integer()}
Runs fun up to config[:max_attempts] times, retrying as long as the
result is transient (a retryable HTTP status or a transient transport
error) and attempts remain, sleeping with jittered backoff in between.
Returns {result, attempts} — fun's final return value and the number
of times it was actually called.
Whether an adapter's raw {:error, reason} payload looks transient.