[opam-devel] ANNOUNCE: OWS, the Opam Wheather Service

Roberto Di Cosmo roberto at dicosmo.org
Thu May 7 15:38:35 BST 2015

Dear fellow Opam developers, 

     We are proud to announce the first public release of a new and fully
refactored version of OWS, the Opam Weather Service, and we are now reaching out
to everybody on opam-devel for feedback and contribution to its evolution.

If you are in hurry, the short message is: 

  - explore the dashboard available online at http://ows.irill.org/ ! 

    The packages listed there are arranged by package name and sorted according
    to the number of issues found on all available versions, you can click on a
    package to get details of these issues, and zone-in on specific packages
    using the search box. 

    On http://ows.irill.org/latest/today/summary.html you will find the list of
    the causes of package installability problems, sorted by their impact:
    packages causing the largest number of problems come first, to help focus
    developer energy when improving the quality of the Opam repository

  - use this information to look after the packages you are responsible for:
    hints on how to fix dependency issues are displayed for each package

  - if you want new features, make suggestions or report a bug, look at the
    source code, available under AGPL from https://github.com/OCamlPro/ows
    You are very welcome to contribute using github

Pietro Abate, Roberto Di Cosmo, Louis Gesbert and Fabrice Le Fessant

Here are more details for who wants to know more.

OWS and distcheck

Built on top of the distcheck tool from the dose library [1], OWS scans daily
the packages in the Opam repository to spot all packages that cannot be
installed at all because of dependency issues, and presents a dashboard that
provides a bird's eye overview of the state of the repository.

This static check is blazingly fast and does not require any physical
installation: it catches *all* dependency issues, and it catches *only*
dependency issues, so it does not replaces the other testing tools that are
needed to catch compilation, configuration and installation issues encountered
when actually deploying a package.

A dashboard based on distcheck has been used in the Debian distribution for
almost ten years [2], and we know well that it can be extremely beneficial to
improve a package repository if it is properly integrated in a quality assurance

A full paper describing how distcheck has been used is going to be presented at
MSR 2015 in a week [3]; a preprint is already availabe [4].

The new OWS

An experimental prototype of OWS has been running for almost a year; the new
version we unveil today is rebuilt from scratch in order to:

 - clearly separate the presentation of the results in a dashboard from the
   distcheck backend from dose: this required changes to opam, dose and

 - provide improved presentation of the results, in order to facilitate
   the identification of the most problematic packages

 - make available all relevant source code, properly released under an
   Open Source licence, written by Pietro Abate (Inria/Irill)

[1] http://dose.gforge.inria.fr/
[2] http://qa.debian.org/dose
[3] http://2015.msrconf.org/program.php 
[4] http://www.dicosmo.org/preprints/msr-2015-distcheck.pdf

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