From a19f606aad717fe5c9c69237c3af53feb547115e Mon Sep 17 00:00:00 2001 From: Julian Andres Klode Date: Wed, 22 Feb 2023 14:14:52 +0100 Subject: Initial support for snapshot servers, apt --snapshot option Provide snapshot support for offical Debian and Ubuntu archives. There are two ways to enable snapshots for sources: 1. Add Snapshot: yes to your sources file ([snapshot=yes]). This will allow you to specify a snapshot to use when updating or installing using the --snapshot,-S option. 2. Add Snapshot: ID to your sources files to request a specific snapshot for this source. Snapshots are discovered using Label and Origin fields in the Release file of the main source, hence you need to have updated the source at least once before you can use snapshots. The Release file may also declare a snapshots server to use, similar to Changelogs, it can contain a Snapshots field with the values: 1. `Snapshots: https://example.com/@SNAPSHOTID@` where `@SNAPSHOTID@` is a placeholder that is replaced with the requested snapshot id 2. `Snapshots: no` to disable snapshot support for this source. Requesting snapshots for this source will result in a failure to load the source. The implementation adds a SHADOWED option to deb source entries, and marks the main entry as SHADOWED when a snapshot has been requested, which will cause it to be updated, but not included in the generated cache. The concern here was that we need to keep generating the shadowed entries because the cleanup in `apt update` deletes any files not queued for download, so we gotta keep downloading the main source. This design is not entirely optimal, but avoids the pitfalls of having to reimplement list cleanup. Gaps: - Ubuntu Pro repositories and PPAs are not yet supported. --- doc/sources.list.5.xml | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'doc/sources.list.5.xml') diff --git a/doc/sources.list.5.xml b/doc/sources.list.5.xml index 478694c77..4fa7a245b 100644 --- a/doc/sources.list.5.xml +++ b/doc/sources.list.5.xml @@ -392,6 +392,23 @@ Signed-By: or, if that fails, a Release file and its associated Release.gpg file. By setting this option, the specified path will be tried instead of the InRelease file, and the fallback to Release files will be disabled. + + + () + allows selecting an earlier version of the archive from the snapshot service. Supported + values are: + + + enable to allow selecting a snapshot with the option, or + + + a snapshot ID to select a specific snapshot. + + + + Snapshot IDs are usually timestamps in the form of YYYYMMDDTHHMMSSZ, such as + 20220102T030405Z which is the January 2nd, 2022 at 03:04:05 UTC, servers may + however support additional types of IDs, and APT does not perform any checks so far. -- cgit v1.2.3-70-g09d2