| 1 |
g2boojum |
1.1 |
GLEP: 9
|
| 2 |
|
|
Title: Gentoo Package Update System
|
| 3 |
g2boojum |
1.3 |
Version: $Revision: 1.2 $
|
| 4 |
|
|
Last-Modified: $Date: 2003/07/25 22:32:20 $
|
| 5 |
g2boojum |
1.1 |
Author: John J. Whitney <jjw@linuxmail.org>
|
| 6 |
g2boojum |
1.3 |
Status: deferred
|
| 7 |
g2boojum |
1.1 |
Type: Standards Track
|
| 8 |
|
|
Content-Type: text/x-rst
|
| 9 |
|
|
Created: 19-Jul-2003
|
| 10 |
|
|
Post-History: 25-Jul-2003
|
| 11 |
|
|
|
| 12 |
|
|
|
| 13 |
|
|
Abstract
|
| 14 |
|
|
========
|
| 15 |
|
|
|
| 16 |
|
|
This document proposes an official package updating system for Gentoo Linux.
|
| 17 |
|
|
The Deltup project has been developed for this purpose. [#DELTUP]_
|
| 18 |
|
|
|
| 19 |
|
|
As packages grow larger the amount of redundant data keeps increasing. Updating
|
| 20 |
|
|
existing tarballs by patching is the natural way to handle source updates.
|
| 21 |
|
|
|
| 22 |
|
|
Motivation
|
| 23 |
|
|
==========
|
| 24 |
|
|
|
| 25 |
|
|
This system will reduce mirror loads (potentially mirror size as well) and
|
| 26 |
|
|
significantly speed up downloads, making Gentoo much more attractive for users
|
| 27 |
|
|
with low-bandwidth connections.
|
| 28 |
|
|
|
| 29 |
|
|
Server Implementation
|
| 30 |
|
|
=====================
|
| 31 |
|
|
|
| 32 |
|
|
I propose that the patches be put onto the Gentoo Mirrors and stored in a new
|
| 33 |
|
|
directory called "patchfiles" which could be placed beside "distfiles".
|
| 34 |
|
|
|
| 35 |
|
|
It would be advantageous to have a list of available patches within the portage
|
| 36 |
|
|
tree so that it can be updated during "emerge sync". A file named "dtu.list"
|
| 37 |
|
|
can be created and placed in $PORTDIR/profiles.
|
| 38 |
|
|
|
| 39 |
|
|
If a machine can be set up to generate patches it should contain a local mirror
|
| 40 |
|
|
of distfiles which it can monitor for added packages. When a package is added
|
| 41 |
|
|
to distfiles the machine can try to determine the previous tarball so a patch
|
| 42 |
|
|
can be made and placed in the patchfiles dir. In addition, special-case patches
|
| 43 |
|
|
can be added manually.
|
| 44 |
|
|
|
| 45 |
|
|
The dtu.list file will be maintained by a special script. Whenever patches
|
| 46 |
|
|
are added or removed to the patchfiles dir, the script will make necessary
|
| 47 |
|
|
additions/removals in dtu.list. This will be done with minimal changes in the
|
| 48 |
|
|
file so it can be synchronized efficiently.
|
| 49 |
|
|
|
| 50 |
|
|
Client Implementation
|
| 51 |
|
|
=====================
|
| 52 |
|
|
|
| 53 |
|
|
The system will be optional for users and can be enabled by making portage
|
| 54 |
|
|
invoke efetch through the FETCHCOMMAND environment variable [#TINYHOWTO]_.
|
| 55 |
|
|
|
| 56 |
|
|
When a package fetch is requested, the efetch/fetchcommand scripts (part of
|
| 57 |
|
|
Deltup) will scan the dtu.list file for updates and try downloading and applying
|
| 58 |
|
|
them if they exist, or fall back to a full package download if they don't or if
|
| 59 |
|
|
the patching process fails.
|
| 60 |
|
|
|
| 61 |
|
|
Rationale
|
| 62 |
|
|
=========
|
| 63 |
|
|
The most controversial feature has been the addition of dtu.list to the portage
|
| 64 |
|
|
tree, so in this section I will list the reasons I support it.
|
| 65 |
|
|
|
| 66 |
|
|
- Flexibility. Without it, there must be a standard naming scheme which we
|
| 67 |
|
|
would be stuck with once the system is in place. Changing the system would
|
| 68 |
|
|
require serious compatibility breaks. With the dtu.list file we can change
|
| 69 |
|
|
the naming scheme easily without problems, or even have several different
|
| 70 |
|
|
naming schemes.
|
| 71 |
|
|
|
| 72 |
|
|
- Features. Without patch information detecting different upgrade paths would
|
| 73 |
|
|
be impossible. Split package patching would also be impossible. If the info
|
| 74 |
|
|
is available we can use it to find the quickest upgrade path, like jumping
|
| 75 |
|
|
from a .0 release, or even disable certain patches if there are problems with
|
| 76 |
|
|
them.
|
| 77 |
|
|
|
| 78 |
|
|
- It would be impossible to know which packages to upgrade from in some cases,
|
| 79 |
|
|
including renamed packages.
|
| 80 |
|
|
|
| 81 |
|
|
- Knowing which patches are available will eliminate the overhead of attempting
|
| 82 |
|
|
to download patches which don't exist.
|
| 83 |
|
|
|
| 84 |
|
|
The dtu.list file will contain several hundred kilobytes of data. That has
|
| 85 |
|
|
caused some concern over how efficiently it can be rsynced. To address these
|
| 86 |
|
|
concerns the file's format will be plaintext and care has been taken to
|
| 87 |
|
|
minimize the number of changes as removals/additions are made.
|
| 88 |
|
|
|
| 89 |
|
|
Backwards Compatibility
|
| 90 |
|
|
=======================
|
| 91 |
|
|
|
| 92 |
|
|
There are no backwards compatibility issues since Deltup can generate correct
|
| 93 |
|
|
package MD5sums.
|
| 94 |
|
|
|
| 95 |
|
|
|
| 96 |
|
|
Conclusion
|
| 97 |
|
|
==========
|
| 98 |
|
|
|
| 99 |
|
|
I suggest we start with a scaled-down implementation and provide more as the
|
| 100 |
|
|
demand increases. All of the necesary code is already written and working in
|
| 101 |
|
|
non-official tests.
|
| 102 |
|
|
|
| 103 |
|
|
References
|
| 104 |
|
|
==========
|
| 105 |
|
|
|
| 106 |
|
|
.. [#DELTUP] http://sourceforge.net/projects/deltup
|
| 107 |
|
|
.. [#PATCHES] ftp://sunsite.dk/projects/deltup/patchfiles
|
| 108 |
|
|
.. [#TINYHOWTO] Tiny Deltup HOWTO
|
| 109 |
|
|
(http://www.thedoh.com/linux/HOWTO/deltup)
|
| 110 |
|
|
|
| 111 |
|
|
Copyright
|
| 112 |
|
|
=========
|
| 113 |
|
|
|
| 114 |
|
|
This document has been placed in the public domain.
|
Parent Directory
| 
Revision Log