This avoids some apparently otherwise unsolveable problems involving
races that resulted in the manifest listing bundles that were deleted.
Removed the annex-max-git-bundles config because it can't actually
result in deleting old bundles. It would still be possible to have a
config that controls how often to do a full push, which would avoid
needing to download too many bundles on clone, as well as needing to
checkpresent too many bundles in verifyManifest. But it would need a
different name and description.
Added a backup manifest key, which is used if the main manifest key is
not present. When uploading a new Manifest, it makes sure that it never
drops one key except when the other key is present.
It's entirely possible for the two manifest keys to get out of sync, due
to races. The main one wins when it's present, it is possible for the
main one being dropped to expose the backup one, which has a different
push recorded.
On push, first try to drop all outManifest keys listed in the current
manifest file, which resumes from an interrupted push that didn't
get a chance to delete those keys.
The new manifest gets its outManifest populated with the keys that were
in the old manifest, plus any of the keys that were unable to be
dropped.
Note that it would be possible for uploadManifest to skip dropping old
keys at all. The old keys would get dropped on the next push. But it
seems better to delete stuff immediately rather than waiting. And the
extra work is limited to push and typically is small.
A remote where dropKey always fails will result in an outManifest that
grows longer and longer. It would be possible to check if the remote
has appendonly = True and avoid populating the outManifest. Of course,
an appendonly remote will grow with every git push anyway. And currently
only Remote.GitLFS sets that, which can't be used as a git-remote-annex
remote anyway.
Implemented alternateJournal, which git-remote-annex
uses to avoid any writes to the git-annex branch while setting up
a special remote from an annex:: url.
That prevents the remote.log from being overwritten with the special
remote configuration from the url, which might not be 100% the same as
the existing special remote configuration.
And it prevents an overwrite deleting of other stuff that was
already in the remote.log.
Also, when the branch was created by git-remote-annex, only delete it
at the end if nothing else has been written to it by another command.
This fixes the race condition described in
797f27ab05, where git-remote-annex
set up the branch and git-annex init and other commands were
run at the same time and their writes to the branch were lost.
This turns out to only be necessary is edge cases. Most of the
time, git-annex unused --from remote doesn't see git-remote-annex keys
at all, because it does not record a location log for them.
On the other hand, git-annex unused does find them, since it does not
rely on the location log. And that's good because they're a local cache
that the user should be able to drop.
If, however, the user ran git-annex unused and then git-annex move
--unused --to remote, the keys would have a location log for that
remote. Then git-annex unused --from remote would see them, and would
consider them unused. Even when they are present on the special remote
they belong to. And that risks losing data if they drop the keys from
the special remote, but didn't expect it would delete git branches they
had pushed to it.
So, make git-annex unused --from skip git-remote-annex keys whose uuid
is the same as the remote.
I hope to support importtree=yes eventually, but it does not currently
work.
Added remote.<name>.allow-encrypted-gitrepo that needs to be set to
allow using it with encrypted git repos.
Note that even encryption=pubkey uses a cipher stored in the git repo
to encrypt the keys stored in the remote. While it would be possible to
not encrypt the GITBUNDLE and GITMANIFEST keys, and then allow using
encryption=pubkey, it doesn't currently work, and that would be a
complication that I doubt is worth it.
Updating the remote list needs the config to be written to the git-annex
branch, which was not done for good reasons. While it would be possible
to instead use Remote.List.remoteGen without writing to the branch, I
already have a plan to discard git-annex branch writes made by
git-remote-annex, so the simplest fix is to write the config to the
branch.
Sponsored-by: k0ld on Patreon
Put the annex objects in .git/annex/objects/ inside the export remote.
This way, when importing from the remote, they will be filtered out.
Note that, when importtree=yes, content identifiers are used, and this
means that pushing to a remote updates the git-annex branch. Urk.
Will need to try to prevent that later, but I already had a todo about
that for other reasons.
Untested!
Sponsored-By: Brock Spratlen on Patreon
Otherwise, it can be confusing to clone from a wrong url, since it fails
to download a manifest and so appears as if the remote exists but is empty.
Sponsored-by: Jack Hill on Patreon
This will eventually be used to recover from an interrupted fullPush
and drop the old bundle keys it was unable to delete.
Sponsored-by: Luke T. Shumaker on Patreon
Update its todo with remaining items.
Add changelog entry.
Simplified internals document to no longer be notes to myself, but
target users who want to understand how the data is stored
and might want to extract these repos manually.
Sponsored-by: Kevin Mueller on Patreon
Making GITBUNDLE be in the backend list allows those keys to be
hashed to verify, both when git-remote-annex downloads them, and by other
transfers and by git fsck.
GITMANIFEST is not in the backend list, because those keys will never be
stored in .git/annex/objects and can't be verified in any case.
This does mean that git-annex version will include GITBUNDLE in the list
of backends.
Also documented these in backends.mdwn
Sponsored-by: Kevin Mueller on Patreon
Not quite there yet.
Also, changed the format of GITBUNDLE keys to use only one '-'
after the UUID. A sha256 does not contain that character, so can just
split at the last one.
Amusingly, the sha256 will probably not actually be verified. A git
bundle contains its own checksums that git uses to verify it. And if
someone wanted to replace the content of a GITBUNDLE object, they
could just edit the manifest to use a new one whose sha256 does verify.
Sponsored-by: Nicholas Golder-Manning
Changed the format of the url to use annex: rather than annex::
The reason is that in the future, might want to support an url that
includes an uriAuthority part, eg:
annex://foo@example.com:42/358ff77e-0bc3-11ef-bc49-872e6695c0e3?type=directory&encryption=none&directory=/mnt/foo/"
To parse that foo@example.com:42 as an uriAuthority it needs to start with
annex: rather than annex::
That would also need something to be done with uriAuthority, and also
the uriPath (the UUID) is prefixed with "/" in that example. So the
current parser won't handle that example currently. But this leaves the
possibility for expansion.
Sponsored-by: Joshua Antonishen on Patreon
The UUID is included in the GITMANIFEST in order to allow a single
key/value store to be used to store several special remotes, without any
namespacing. In that situation though, if the same ref is pushed to two
special remotes, it will result in git bundles with the same content.
Which is ok, until a re-push happens to one of the special remote.
At that point, the old git bundle will be deleted. That will prevent
fetching it from the other special remote, where the re-push has not
happened.
Adding the UUID avoids this problem.
And document remote.<name>.git-remote-annex-max-bundles which will
configure it.
datalad-annex uses a similar url format, but with some enhancements.
See https://github.com/datalad/datalad-next/blob/main/datalad_next/gitremotes/datalad_annex.py
I added the UUID to the URL, because it is needed in order to pick out which
manifest file to use. The design allows for a single key/value store to have
several special remotes all stored in it, and so the manifest includes
the UUID in its name.
While datalad-annex allows datalad-annex::<url>?, and allows referencing
peices of the url in the parameters, needing the UUID prevents
git-remote-annex from supporting that syntax. And anyway, it is a
complication and I want to keep things simple for now.
Sponsored-by: unqueued on Patreon
Added to git-annex_proxies todo because this is something OpenNeuro
would need in order to use the git-annex proxy.
Sponsored-by: Dartmouth College's OpenNeuro project
Rather than requiring the last listed bundle in the manifest include all
refs that are in the remote, build up refs from each bundle listed in
the manifest.
This fixes a bug where pushing first a new branch foo from one clone,
and then pushing a new branch bar from another clone, caused the second
push to lose branch foo. Now the second push will add a new bundle, but
the foo ref in the bundle from the first push will still be used.
Pushing a deletion of a ref now has to delete all bundles and push a new
bundle with only the remaining refs in it.
In a "list for-push", it now has to unbundle all bundles, in order for a
deletion repush to have available all objects. (And a non-deletion push
can also rely on refs/namespaces/mine/ being up-to-date.)
It would have been possible to fix the bug by only making it do that
unbundling in "list for-push", without changing what's stored in the
bundles. But I think I prefer to populate the bundles this way. For one
thing, deleting a pushed ref now really deletes all data relating to it,
rather than leaving it present in old bundles. For another, it's easier
to explain since there is no special case for the last bundle. And, it
will often result in smaller bundles.
Note that further efficiency gains are possible with respect to what
objects are included in an incremental bundle. Two XXX comments
document how to reduce excess objects. It didn't seem worth implementing
those optimisations in this proof of concept code.
Sponsored-by: Brock Spratlen on Patreon
In a situation where there are two repos that are diverged and each pushes
in turn to git-remote-annex, the first to push updates it. Then the second
push fails because it is not a fast-forward. The problem is, before git
push fails with "non-fast-forward", it actually calls git-remote-annex
with push.
So, to the user it appears as if the push failed, but it actually reached
the remote, and overwrote the other push!
The only solution to this seems to be for git-remote-annex push to notice
when a non-force-push would overwrite a ref stored in the remote, and
refuse to push that ref, returning an error to git. This seems strange,
why would git make remote helpers implement that when it later checks the
same thing itself?
With this fix, it's still possible for a race to overwrite a change to
the MANIFEST and lose work that was pushed from the other repo. But that
needs two pushes to be running at the same time. From the user's
perspective, that situation is the same as if one repo pushed new work,
then the other repo did a git push --force, overwriting the first repo's
push. In the first repo, another push will then fail as a non
fast-forward, and the user can recover as usual. But, a MANIFEST
overwrite will leave bundle files in the remote that are not listed in
the MANIFEST. It seems likely that git-annex will eventually be able to
detect that after the fact and clean it up. Eg, it can learn all bundles
that are stored in the remote using the location log, and compare them
to the MANIFEST to find bundles that got lost.
The race can also appear to the user as if they pushed a ref, but then
it got deleted from the remote. This happens when two two pushes are
pushing different ref names. This might be harder for the user to
notice; git fetch does not indicate that a remote ref got deleted.
They would have to use git fetch --prune to notice the deletion.
Once the user does notice, they can re-push their ref to recover.
Sponsored-by: Jack Hill on Patreon
This is a shell script, so not final code, and it does not use git-annex
at all, but it shows how to push to git bundles, listed in a MANIFEST,
the same as the git-remote-annex program will eventually do.
While developing this, I realized that the design needed to be changed
slightly regarding where refs are stored. Since a push can delete a ref
from a remote, storing each newly pushed ref in a bundle won't work,
because deleting a ref would then entail deleting all old bundles and
re-uploading from scratch. So instead, only the refs in the last bundle
listed in the MANIFEST are the active refs. Any refs in prior bundles
are just old refs that were stored previously (a reflog as it were).
That means that, in a situation where two different people are pushing
to the same special remote from different repos, whoever pushes last
wins. Any refs pushed by the other person earlier will be ignored. This
may not be desirable, and git-annex might be able use the git-annex
branch to detect such situations and rescue the refs that got lost. Even
without such a recovery process though, the refs that the other person
thought they pushed will be preserved in their refs/namespaces/mine, so
a pull followed by a push will generally resolve the situation.
Note that the use of refs/namespaces/mine in the bundle is not really
desirable, and it might be worth making a local clone of the repo in
order to set up the refs that will be put in the bundle. Which seems to
be the only way to avoid needing that. But it does need to maintain
the refs/namespaces/mine/ in the git repo in order to remember what refs
have been pushed to the remote before, in order to include them in the
next bundle pushed. A name that includes the remote uuid will be needed
in the final implementation.
Anyway, this shell script seems to fully work, including incremental
pushing, force pushing, and pushes that delete refs.
Sponsored-by: Brett Eisenberg on Patreon
Added rclone special remote, which can be used without needing to install
the git-annex-remote-rclone program. This needs a new version of rclone,
which supports "rclone gitannex".
This is implemented as a variant of an external special remote, that
runs "rclone gitannex" instead of the usual git-annex-remote- command.
Parameterized Remote.External to support that.
Sponsored-by: Luke T. Shumaker on Patreon
Test suite passes this time. When committing the adjusted branch, use
the old method to make a message that old git-annex can consume. Also
made the code accept the new message, so that eventually
commitTreeExactMessage can be removed.
Sponsored-by: Kevin Mueller on Patreon
This reverts commit cee12f6a2f.
This commit broke git-annex init run in a repo that was cloned from a
repo with an adjusted branch checked out.
The problem is that findAdjustingCommit was not able to identify the
commit that created the adjusted branch. It seems that there is an extra
"\n" at the end of the commit message that it does not expect.
Since backwards compatability needs to be maintained, cannot just make
findAdjustingCommit accept it with the "\n". Will have to instead
have one commitTree variant that uses the old method, and use it for
adjusted branch committing.
sync, assist, import: Allow -m option to be specified multiple times, to
provide additional paragraphs for the commit message.
The option parser didn't allow multiple -m before, so there is no risk of
behavior change breaking something that was for some reason using multiple
-m already.
Pass through to git commands, so that the method used to assemble the
paragrahs is whatever git does. Which might conceivably change in the
future.
Note that git commit-tree has supported -m since git 1.7.7. commitTree
was probably not using it since it predates that version. Since the
configure script prevents building git-annex with git older than 2.1,
there is no risk that it's not supported now.
Sponsored-by: Nicholas Golder-Manning on Patreon
While redundant concurrent transfers were already prevented in most
cases, it failed to prevent the case where two different repositories were
sending the same content to the same repository. By removing the uuid
from the transfer lock file for Download transfers, one repository
sending content will block the other one from also sending the same
content.
In order to interoperate with old git-annex, the old lock file is still
locked, as well as locking the new one. That added a lot of extra code
and work, and the plan is to eventually stop locking the old lock file,
at some point in time when an old git-annex process is unlikely to be
running at the same time.
Note that in the case of 2 repositories both doing eg
`git-annex copy foo --to origin`
the output is not that great:
copy b (to origin...)
transfer already in progress, or unable to take transfer lock
git-annex: transfer already in progress, or unable to take transfer lock
97% 966.81 MiB 534 GiB/s 0sp2pstdio: 1 failed
Lost connection (fd:14: hPutBuf: resource vanished (Broken pipe))
Transfer failed
Perhaps that output could be cleaned up? Anyway, it's a lot better than letting
the redundant transfer happen and then failing with an obscure error about
a temp file, which is what it did before. And it seems users don't often
try to do this, since nobody ever reported this bug to me before.
(The "97%" there is actually how far along the *other* transfer is.)
Sponsored-by: Joshua Antonishen on Patreon
What this can currently be used for is only to change an url from being
used by a special remote to being used by the web remote.
This could have been a --move-from option to registerurl. But, that would
have complicated its option and --batch processing, and also would have
complicated unregisterurl, which is implemented on top of
Command.Registerurl. So, a separate command was actually less complicated
to implement.
The generic description of the command is because I want to make this
command a catch-all for other url updating kind of things, if there are
ever any more. Also because it was hard to come up with a good name for the
specific action. I considered `git-annex moveurl`, but that seems to
indicate data is perhaps actually being moved, and seems to sit at the same
level as addurl and rmurl, and this command is at the plumbing
level of registerurl and unregisterurl.
Sponsored-by: Dartmouth College's DANDI project
