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reorg, and add a link to a good forum post todo

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Joey Hess 2012-07-06 14:21:26 -04:00
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doc/design/assistant/syncing.mdwn
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@ -3,27 +3,6 @@ all the other git clones, at both the git level and the key/value level.
## action items
* on-disk transfers in progress information files (read/write/enumerate)
**done**
* locking for the files, so redundant transfer races can be detected,
and failed transfers noticed **done**
* transfer info for git-annex-shell **done**
* update files as transfers proceed. See [[progressbars]]
(updating for downloads is easy; for uploads is hard)
* add Transfer queue TChan **done**
* add TransferInfo Map to DaemonStatus for tracking transfers in progress.
**done**
* Poll transfer in progress info files for changes (use inotify again!
wow! hammer, meet nail..), and update the TransferInfo Map **done**
* enqueue Transfers (Uploads) as new files are added to the annex by
Watcher. **done**
* enqueue Tranferrs (Downloads) as new dangling symlinks are noticed by
Watcher. **done**
* Write basic Transfer handling thread. Multiple such threads need to be
able to be run at once. Each will need its own independant copy of the
Annex state monad. **done**
* Write transfer control thread, which decides when to launch transfers.
**done**
* Check that download transfer triggering code works (when a symlink appears
and the remote does *not* upload to us.
* Investigate why transfers seem to block other git-annex assistant work.
@ -36,30 +15,21 @@ all the other git clones, at both the git level and the key/value level.
through to, at least, rsync. A good job for an hour in an
airport somewhere.
## git syncing
## longer-term TODO
1. Can use `git annex sync`, which already handles bidirectional syncing.
When a change is committed, launch the part of `git annex sync` that pushes
out changes. **done**; changes are pushed out to all remotes in parallel
1. Watch `.git/refs/remotes/` for changes (which would be pushed in from
another node via `git annex sync`), and run the part of `git annex sync`
that merges in received changes, and follow it by the part that pushes out
changes (sending them to any other remotes).
[The watching can be done with the existing inotify code! This avoids needing
any special mechanism to notify a remote that it's been synced to.]
**done**
1. Periodically retry pushes that failed. **done** (every half an hour)
1. Also, detect if a push failed due to not being up-to-date, pull,
and repush. **done**
2. Use a git merge driver that adds both conflicting files,
so conflicts never break a sync. **done**
3. Investigate the XMPP approach like dvcs-autosync does, or other ways of
* Investigate the XMPP approach like dvcs-autosync does, or other ways of
signaling a change out of band.
4. Add a hook, so when there's a change to sync, a program can be run
* Add a hook, so when there's a change to sync, a program can be run
and do its own signaling.
5. --debug will show often unnecessary work being done. Optimise.
6. It would be nice if, when a USB drive is connected,
* --debug will show often unnecessary work being done. Optimise.
* It would be nice if, when a USB drive is connected,
syncing starts automatically. Use dbus on Linux?
* This assumes the network is connected. It's often not, so the
[[cloud]] needs to be used to bridge between LANs.
* Configurablity, including only enabling git syncing but not data transfer;
only uploading new files but not downloading, and only downloading
files in some directories and not others. See for use cases:
[[forum/Wishlist:_options_for_syncing_meta-data_and_data]]
## data syncing
@ -84,10 +54,42 @@ reachable remote. This is worth doing first, since it's the simplest way to
get the basic functionality of the assistant to work. And we'll need this
anyway.
## other considerations
## done
It would be nice if, when a USB drive is connected,
syncing starts automatically. Use dbus on Linux?
1. Can use `git annex sync`, which already handles bidirectional syncing.
When a change is committed, launch the part of `git annex sync` that pushes
out changes. **done**; changes are pushed out to all remotes in parallel
1. Watch `.git/refs/remotes/` for changes (which would be pushed in from
another node via `git annex sync`), and run the part of `git annex sync`
that merges in received changes, and follow it by the part that pushes out
changes (sending them to any other remotes).
[The watching can be done with the existing inotify code! This avoids needing
any special mechanism to notify a remote that it's been synced to.]
**done**
1. Periodically retry pushes that failed. **done** (every half an hour)
1. Also, detect if a push failed due to not being up-to-date, pull,
and repush. **done**
2. Use a git merge driver that adds both conflicting files,
so conflicts never break a sync. **done**
This assumes the network is connected. It's often not, so the
[[cloud]] needs to be used to bridge between LANs.
* on-disk transfers in progress information files (read/write/enumerate)
**done**
* locking for the files, so redundant transfer races can be detected,
and failed transfers noticed **done**
* transfer info for git-annex-shell **done**
* update files as transfers proceed. See [[progressbars]]
(updating for downloads is easy; for uploads is hard)
* add Transfer queue TChan **done**
* add TransferInfo Map to DaemonStatus for tracking transfers in progress.
**done**
* Poll transfer in progress info files for changes (use inotify again!
wow! hammer, meet nail..), and update the TransferInfo Map **done**
* enqueue Transfers (Uploads) as new files are added to the annex by
Watcher. **done**
* enqueue Tranferrs (Downloads) as new dangling symlinks are noticed by
Watcher. **done**
* Write basic Transfer handling thread. Multiple such threads need to be
able to be run at once. Each will need its own independant copy of the
Annex state monad. **done**
* Write transfer control thread, which decides when to launch transfers.
**done**