From 7b9dea5a7c43fd91bcd23d1585d39a726d098285 Mon Sep 17 00:00:00 2001 From: Felix Moessbauer Date: Fri, 8 Nov 2024 15:04:17 +0100 Subject: http: use Retry-After HTTP header to optimize retries Some mirrors like snapshot.debian.org apply strict http rate limits. While apt already has an exponential backoff mechanism implemented, this is not sufficient due to the following reasons: 1. all retries happen roughly at the same time 2. the retry-after information from the server is not used We fix this by improving the algorithm: First, if present, the timestamp or duration of the Retry-After header is added to the exponential backoff, optimizing for success-on-second-try. Second, a random delay is added (delay += [0, delay]) to distribute the retries to not immediately run into the limit again. To avoid super-long delays, this is capped by the configured maximum delay. This logic only becomes active if the option Acquire::Retries::HandleRetryAfter is enabled. Signed-off-by: Felix Moessbauer --- doc/examples/configure-index | 1 + 1 file changed, 1 insertion(+) (limited to 'doc') diff --git a/doc/examples/configure-index b/doc/examples/configure-index index 72ce1fe3a..feadca8d2 100644 --- a/doc/examples/configure-index +++ b/doc/examples/configure-index @@ -249,6 +249,7 @@ Acquire Delay "" { // whether to backoff between retries using the delay: method Maximum ""; // maximum number of seconds to delay an item per retry }; + HandleRetryAfter ""; // whether to respect the wait time of the Retry-After header }; Source-Symlinks ""; ForceHash ""; // hashmethod used for expected hash: sha256, sha1 or md5sum -- cgit v1.2.3-70-g09d2