pacman-accel

#!/usr/bin/ruby
#
# A simple local redirector for pacman, to get you the latest packages and
# utilize available mirrors.
#
# Usage:
# - Set multiple mirrors in /etc/pacman.d/mirrorlist-accel with ordering:
# https://fastest-mirror-but-updates-once-a-day/archlinux/
# https://relatively-slower-mirror-that-updates-more-frequently/archlinux/
# ...
# https://pkgbuild-dot-com-or-another-mirror-that-gives-you-the-latest-packages/
#
# - Set /etc/pacman.d/mirrorlist to this redirector:
# Server = http://127.0.0.1:4567/$repo/os/$arch

require 'http'
require 'sinatra'

config = ENV.fetch("PACMAN_ACCEL_CONF", "/etc/pacman.d/mirrorlist-accel")
mirrors = File.readlines(config).filter_map { |line| line.strip if line && line[0] != "#" }

get '/*' do |path|
    # Set TIER 0/1 mirrors as the last one, for:
    #  - DB syncing
    #  - Download fallback
    # These two use cases always the same server for consistency.
    mirror = mirrors[-1]

    unless path.end_with? '.db'
        # Find a faster mirror with the requested file present
        mirrors[..-2].each { |m|
            begin
                response = HTTP.head(m + path)
            rescue => e
                logger.error "skipping mirror #{m}, failed to HEAD: #{e}"
                next
            end
            if response.status == 200
                mirror = m
                break
            else
                logger.info "skipping #{m} for #{path}, code: #{response.status}"
            end
        }
    end

    logger.info "redirecting to #{mirror + path}"
    redirect mirror + path, 302
end

set :bind, ENV.fetch("PACMAN_ACCEL_BIND", "127.0.0.1")
set :port, ENV.fetch("PACMAN_ACCEL_PORT", "4567")
set :host_authorization, { permitted_hosts: [] }