git-annex/doc/design/assistant/upgrading.mdwn
Joey Hess b6d46c212e git-annex (5.20140402) unstable; urgency=medium
* unannex, uninit: Avoid committing after every file is unannexed,
    for massive speedup.
  * --notify-finish switch will cause desktop notifications after each
    file upload/download/drop completes
    (using the dbus Desktop Notifications Specification)
  * --notify-start switch will show desktop notifications when each
    file upload/download starts.
  * webapp: Automatically install Nautilus integration scripts
    to get and drop files.
  * tahoe: Pass -d parameter before subcommand; putting it after
    the subcommand no longer works with tahoe-lafs version 1.10.
    (Thanks, Alberto Berti)
  * forget --drop-dead: Avoid removing the dead remote from the trust.log,
    so that if git remotes for it still exist anywhere, git annex info
    will still know it's dead and not show it.
  * git-annex-shell: Make configlist automatically initialize
    a remote git repository, as long as a git-annex branch has
    been pushed to it, to simplify setup of remote git repositories,
    including via gitolite.
  * add --include-dotfiles: New option, perhaps useful for backups.
  * Version 5.20140227 broke creation of glacier repositories,
    not including the datacenter and vault in their configuration.
    This bug is fixed, but glacier repositories set up with the broken
    version of git-annex need to have the datacenter and vault set
    in order to be usable. This can be done using git annex enableremote
    to add the missing settings. For details, see
    http://git-annex.branchable.com/bugs/problems_with_glacier/
  * Added required content configuration.
  * assistant: Improve ssh authorized keys line generated in local pairing
    or for a remote ssh server to set environment variables in an
    alternative way that works with the non-POSIX fish shell, as well
    as POSIX shells.

# imported from the archive
2014-04-02 21:42:53 +01:00

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Markdown

The assistant should support upgrading itself.
## non-distro upgrades
When git-annex was installed from this website, the assistant should poll
periodically (once a day or so) to see if there is a new version.
It downloads, over https, a .info file, which contains a serialized data
type containing upgrade information. The url it's downloaded from is
configured by setting `UPGRADE_LOCATION` when building git-annex on the
autobuilders.
When a new version is found, the webapp prompts the user to start the
upgrade. (annex.autoupgrade can be set to true to upgrade w/o prompting.)
The upgrade process is automatic, and rather tricky. The file is downloaded
using git-annex (as a regular key!), and is then unpacked into a new
directory, and the programfile updated to point to it. Then git-annex
restarts itself.
### manifest files
To clean up the old installation, a git-annex.MANIFEST file is looked for
in it, and the files listed, as well as empty directories, are deleted.
I don't want to accidentially delete something I didn't ship!
## restart on upgrade
When git-annex is installed from a proper distribution package, there is no
need for the above. But, the assistant still needs to notice when git-annex
get upgraded, and offer to restart (or automatically restart when
annex.autoupgrade is set).
This is done using the DirWatcher, watching the directory containing the
git-annex binary. Or, in the case of a non-distro install, watching the
directory where eg git-annex.linux/ was unpacked.
When an change is detected, restart.
## multi-daemon upgrades
A single system may have multiple assistant daemons running in different
repositories.
In this case, one daemon should do the non-distro upgrade, and the rest
should notice the upgrade and restart.
I don't want every daemon trying to download the file at once..
Approach: The first new version is installed into a stable directory, based
on its version. So, start the upgrade by making this directory. If upgrade
is already in progress, the directory will already exist. (Remove directory
if upgrade fails.)