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 --- apt-pkg/acquire-method.cc | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'apt-pkg/acquire-method.cc') diff --git a/apt-pkg/acquire-method.cc b/apt-pkg/acquire-method.cc index 7b1f4f1b5..13f3fa4dd 100644 --- a/apt-pkg/acquire-method.cc +++ b/apt-pkg/acquire-method.cc @@ -145,9 +145,15 @@ void pkgAcqMethod::Fail(bool Transient) Fail("", Transient); } + +void pkgAcqMethod::Fail(std::string Err, bool Tansient) +{ + std::unordered_map fields; + FailWithContext(Err, Tansient, fields); +} /*}}}*/ // AcqMethod::Fail - A fetch has failed /*{{{*/ -void pkgAcqMethod::Fail(string Err, bool Transient) +void pkgAcqMethod::FailWithContext(std::string Err, bool Transient, std::unordered_map &fields) { if (not _error->empty()) @@ -175,7 +181,6 @@ void pkgAcqMethod::Fail(string Err, bool Transient) if (IP.empty() == false && _config->FindB("Acquire::Failure::ShowIP", true) == true) Err.append(" ").append(IP); - std::unordered_map fields; if (Queue != nullptr) try_emplace(fields, "URI", Queue->Uri); else -- cgit v1.2.3-70-g09d2