What is euscan-ng ?

dev-portage/euscan-ng

euscan-ng is a fork of Bernard Cafarelli's euscan: https://github.com/voyageur/euscan which is a fork of Corentin Chary's euscan: https://github.com/iksaif/euscan

Right now euscan-ng and (legacy) euscan cannot be installed (system-wide) on the same system. euscan-ng is available in src_prepare overlay as a dev package (app-portage/euscan-ng-9999).

This tool allows to check if a given package has new upstream versions or not. It will use different heuristic to scan upstream and grab new versions and related urls.

This tool was designed to mimic debian's uscan, but there is a major difference between the two: uscan uses a specific "watch" file that describes how it should scan packages, while euscan-ng uses only what can already be found in ebuilds. Of course, we could later add some informations in metadata.xml to help euscan-ng do its job more efficiently.

euscan-ng heuristics are described in the "How does-it works?" section.

Examples

$ euscan amatch
 * dev-ruby/amatch-0.2.7 [gentoo]
Ebuild: /home/euscan/local/usr/portage/dev-ruby/amatch/amatch-0.2.7.ebuild
Repository: gentoo
Homepage: http://flori.github.com/amatch/
Description: Approximate Matching Extension for Ruby
 * SRC_URI is 'mirror://rubygems/amatch-0.2.7.gem'
 * Using: http://rubygems.org/api/v1/versions/amatch.json
Upstream Version: 0.2.8 http://rubygems.org/gems/amatch-0.2.8.gem

$ euscan rsyslog
 * app-admin/rsyslog-5.8.5 [gentoo]
Ebuild: /home/euscan/local/usr/portage/app-admin/rsyslog/rsyslog-5.8.5.ebuild
Repository: gentoo
Homepage: http://www.rsyslog.com/
Description: An enhanced multi-threaded syslogd with database support and more.
 * SRC_URI is 'http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.8.5.tar.gz'
 * Scanning: http://www.rsyslog.com/files/download/rsyslog/rsyslog-${PV}.tar.gz
 * Scanning: http://www.rsyslog.com/files/download/rsyslog
 * Generating version from 5.8.5
 * Brute forcing: http://www.rsyslog.com/files/download/rsyslog/rsyslog-${PV}.tar.gz
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.8.6.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.8.7.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.8.8.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.0.tar.gz ... [ ok ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.10.0.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.11.0.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.1.tar.gz ... [ ok ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.2.tar.gz ... [ ok ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.3.tar.gz ... [ ok ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.12.0.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.4.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.5.tar.gz ... [ !! ]
 * Trying: http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.6.tar.gz ... [ !! ]
Upstream Version: 5.9.1 http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.1.tar.gz
Upstream Version: 5.9.0 http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.0.tar.gz
Upstream Version: 5.9.3 http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.3.tar.gz
Upstream Version: 5.9.2 http://www.rsyslog.com/files/download/rsyslog/rsyslog-5.9.2.tar.gz

Hidden settings

You can configure some settings using the command line, but the __init__.py file of the euscan package contains more settings, including blacklists and default settings.

Maybe we should add the ability to use /etc/euscan.conf and ~/.config/euscan/euscan.conf to override these settings.

How does it work ?

euscan has different heuristics to scan upstream and provides multiple "handlers". First, here is a description of the generic handler.

Scanning directories

The first thing to do is to scan directories. It's also what uscan do, but it uses a file that describe what url and regexp to use to match packages.

euscan uses SRC_URI and tries to find the current version (or part of this version) in the resolved SRC_URI and generate a regexp from that.

For example for app-accessibility/dash-4.10.1, SRC_URI is:

mirror://gnome/sources/dasher/4.10/dasher-4.10.1.tar.bz2

euscan will scan pages based on this template:

http://ftp.gnome.org/pub/gnome/sources/dasher/${0}.${1}/dasher-${PV}.tar.bz2

Then, from that, it will scan the top-most directory that doesn't depend on the version, and try to go deeper from here.

Brute force

Like when scanning directories, a template of SRC_URI is built. Then euscan generate next possible version numbers, and tries to download the url generated from the template and the new version number.

For example, running euscan on portage/app-accessibility/festival-freebsoft-utils-0.6:

SRC_URI is 'http://www.freebsoft.org/pub/projects/festival-freebsoft-utils/festival-freebsoft-utils-0.6.tar.gz'
Template is http://www.freebsoft.org/pub/projects/festival-freebsoft-utils/festival-freebsoft-utils-${PV}.tar.gz
Generate version from 0.6: 0.7, 0.8, 0.10, ...
Try new urls: http://www.freebsoft.org/pub/projects/festival-freebsoft-utils/festival-freebsoft-utils-0.7.tar.gz, etc..

Blacklists

euscan uses blacklist for multiple purposes.

BLACKLIST_VERSIONS

For versions that should not be checked at all. sys-libs/libstdc++-v3-3.4 is good example because it's a package which version will always be 3.4 (Compatibility package for running binaries linked against a pre gcc 3.4 libstdc++).

BLACKLIST_PACKAGES

Some packages are dead, but SRC_URI refers to sources that are still being updated, for example: sys-kernel/xbox-sources that uses the same sources as vanilla-sources but is not updated the same way.

SCANDIR_BLACKLIST_URLS

For urls that are not browsable. mirror://gentoo/ is a good example: it's both stupid to scan it and very long/expensive.

BRUTEFORCE_BLACKLIST_PACKAGES and BRUTEFORCE_BLACKLIST_URLS

Disable brute force on those packages and urls. Most of the time it's because upstream is broken and will answer HTTP 200 even if the file doesn't exist.

ROBOTS_TXT_BLACKLIST_DOMAINS

Don't respect robots.txt for these domains (sourcefourge, berlios, github.com).

Site handlers

Pecl/PEAR

A site handler that uses the Pecl/PEAR rest API (http://pear.php.net/manual/en/core.rest.php).

Rubygems

This one uses rubygems's json API (http://guides.rubygems.org/rubygems-org-api/)

PyPI

Uses PyPI's XML rpc API.