This does not avoid all possible races, but it does avoid all likely
ones, and is demonstratably better than git's own handling of races
where files get modified at the same time as it's updating the working
tree.
The main thing this won't detect are not unlikely races where part
of a file gets changed while it's being copied and then the file is
restored to its original condition before the modification check.
No, it's more likely that the limitations of checking inode, size,
and mtime won't detect certian modifications, involving eg mmapped
files.
Purifying exportActions will allow introspecting and modifying it,
which is needed to add progress bar display to it.
Only S3 and WebDAV ran an Annex action while constructing ExportActions.
There was a small performance gain from them doing that, since a
resource was able to be prepared and reused for multiple actions by
Command.Export.
As seen in commit 809cfbbd8a and
5d394023eb S3 and WebDAV actually create a
new handle for each access in normal, non-export use. It doesn't seem
worth making export use of them marginally more efficient than normal
use. It would be better to do that work upfront when constructing the
remote. Or perhaps use a MVar to cache a handle.
This commit was sponsored by Nick Piper on Patreon.
Does nothing yet.
Considered making bup readonly, but while the content can't be removed,
it is able to delete a branch, so didn't.
This commit was supported by the NSF-funded DataLad project.
This will be used to protect against CVE-2018-10859, where an encrypted
special remote is fed the wrong encrypted data, and so tricked into
decrypting something that the user encrypted with their gpg key and did
not store in git-annex.
It also protects against CVE-2018-10857, where a remote follows a http
redirect to a file:// url or to a local private web server. While that's
already been prevented in git-annex's own use of http, external special
remotes, hooks, etc use other http implementations and could still be
vulnerable.
The policy is not yet enforced, this commit only adds the appropriate
metadata to remotes.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
This is groundwork for letting a repo be instantiated the first time
it's actually used, instead of at startup.
The only behavior change is that some old special cases for xmpp remotes
were removed. Where before git-annex silently did nothing with those
no-longer supported remotes, it may now fail in some way.
The additional IO action should have no performance impact as long as
it's simply return.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon
git annex testremote passes.
exportree not implemented yet, although the documentation talks about it,
since it will be the main way this remote will be used.
The adb push/pull progress is displayed for now; it would be better
to consume it and use it to update the git-annex progress bar.
This commit was sponsored by andrea rota.
Was trying to rmdir the file, which had already been deleted, and when that
failed, it skipped trying to delete the parent directories.
Noticed the bug through testremote, but it can't itself detect such
problems as there is no enumeration in the API.
This commit was sponsored by Brock Spratlen on Patreon.
New table needed to look up what filenames are used in the currently
exported tree, for reasons explained in export.mdwn.
Also, added smart constructors for ExportLocation and ExportDirectory to
make sure they contain filepaths with the right direction slashes.
And some code refactoring.
This commit was sponsored by Francois Marier on Patreon.
Not yet called by Command.Export.
WebDAV needs this to clean up empty collections. Also, example.sh turned
out to not be cleaning up directories when removing content
from them, so it made sense for it to use this.
Remote.Directory did not need it, and since its cleanup method for empty
directories is more efficient than what Command.Export will need to do
to find empty directories, it uses Nothing so that extra work can be
avoided.
This commit was sponsored by Thom May on Patreon.
Don't allow "exporttree=yes" to be set when the special remote
does not support exports. That would be confusing since the user would
set up a special remote for exports, but `git annex export` to it would
later fail.
This commit was supported by the NSF-funded DataLad project.
Straightforward enough, except for the needed belt-and-suspenders sanity
checks to avoid foot shooting due to exports not being key/value stores.
* Even when annex.verify=false, always verify from exports.
* Only get files from exports that use a backend that supports
checksum verification.
* Never trust exports, even if the user says to, because then
`git annex drop` would drop content if the export seemed to contain
a copy.
This commit was supported by the NSF-funded DataLad project.
* Only export to remotes that were initialized to support it.
* Prevent storing key/value on export remotes.
* Prevent enabling exporttree=yes and encryption in the same remote.
SetupStage Enable was changed to take the old RemoteConfig.
This allowed only setting exporttree when initially setting up a
remote, and not configuring it later after stuff might already be stored
in the remote.
Went with =yes rather than =true for consistency with other parts of
git-annex. Changed docs accordingly.
This commit was supported by the NSF-funded DataLad project.
This will allow disabling exports for remotes that are not configured to
allow them. Also, exportSupported will be useful for the external
special remote to probe.
This commit was supported by the NSF-funded DataLad project
This avoids needing to deal with the complexity of partially transferred
files in the export. We'd not be able to resume uploading to such a file
anyway, so just avoid them.
The implementation in Remote.Directory is not completely ideal, because
it could leave the temp file hanging around in the export directory.
This only happens if it's killed with -9, or there's a power failure;
normally viaTmp cleans up after itself, even when interrupted. I could
not see a better way to do it though, since the export directory might
be the root of a filesystem.
Also some design thoughts on resuming, which depend on storeExport being
atomic.
This commit was sponsored by Fernando Jimenez on Partreon.
Rather than providing the key to export, provide the file.
When exporting a treeish that contains files that are not annexed,
this will let the content of those files also be exported.
There's still a Key in the interface; it will be used by the external
special remote protocol. A SHA1 key can be used when exporting
non-annexed files.
This commit was sponsored by Brock Spratlen on Patreon.
Implemented so far for the directory special remote.
Several remotes don't make sense to export to. Regular Git remotes,
obviously, do not. Bup remotes almost certianly do not, since bup would
need to be used to extract the export; same store for Ddar. Web and
Bittorrent are download-only. GCrypt is always encrypted so exporting to
it would be pointless. There's probably no point complicating the Hook
remotes with exporting at this point. External, S3, Glacier, WebDAV,
Rsync, and possibly Tahoe should be modified to support export.
Thought about trying to reuse the storeKey/retrieveKeyFile/removeKey
interface, rather than adding a new interface. But, it seemed better to
keep it separate, to avoid a complicated interface that sometimes
encrypts/chunks key/value storage and sometimes users non-key/value
storage. Any common parts can be factored out.
Note that storeExport is not atomic.
doc/design/exporting_trees_to_special_remotes.mdwn has some things in
the "resuming exports" section that bear on this decision. Basically,
I don't think, at this time, that an atomic storeExport would help with
resuming, because exports are not key/value storage, and we can't be
sure that a partially uploaded file is the same content we're currently
trying to export.
Also, note that ExportLocation will always use unix path separators.
This is important, because users may export from a mix of windows and
unix, and it avoids complicating the API with path conversions,
and ensures that in such a mix, they always use the same locations for
exports.
This commit was sponsored by Bruno BEAUFILS on Patreon.
Most remotes have an idempotent setup that can be reused for
enableremote, but in a few cases, it needs to tell which, and whether
a UUID was provided to setup was used.
This is groundwork for making initremote be able to provide a UUID.
It should not change any behavior.
Note that it would be nice to make the UUID always be provided to setup,
and make setup not need to generate and return a UUID. What prevented
this simplification is Remote.Git.gitSetup, which needs to reuse the
UUID of the git remote when setting it up, and so has to return that
UUID.
This commit was sponsored by Thom May on Patreon.
ghc 8 added backtraces on uncaught errors. This is great, but git-annex was
using error in many places for a error message targeted at the user, in
some known problem case. A backtrace only confuses such a message, so omit it.
Notably, commands like git annex drop that failed due to eg, numcopies,
used to use error, so had a backtrace.
This commit was sponsored by Ethan Aubin.
Removed the instance LensGpgEncParams RemoteConfig because it encouraged
code that does not take the RemoteGitConfig into account.
RemoteType's setup was changed to take a RemoteGitConfig,
although the only place that is able to provide a non-empty one is
enableremote, when it's changing an existing remote. This led to several
folow-on changes, and got RemoteGitConfig plumbed through.
Now it suffices to run git remote add, followed by git-annex sync. Now the
remote is automatically initialized for use by git-annex, where before the
git-annex branch had to manually be pushed before using git-annex sync.
Note that this involved changes to git-annex-shell, so if the remote is
using an old version, the manual push is still needed.
Implementation required git-annex-shell be changed, so configlist can
autoinit a repository even when no git-annex branch has been pushed yet.
Unfortunate because we'll have to wait for it to get deployed to servers
before being able to rely on this change in the documentation.
Did consider making git-annex sync push the git-annex branch to repos that
didn't have a uuid, but this seemed difficult to do without complicating it
in messy ways.
It would be cleaner to split a command out from configlist to handle
the initialization. But this is difficult without sacrificing backwards
compatability, for users of old git-annex versions which would not use the
new command.
The directory special remote was not affected in its normal configuration,
since annex-directory is an absolute path normally. But it could fail
when a relative path was used.
The git remote was affected even when an absolute path to it was used in
.git/config, since git-annex now converts all such paths to relative.
Reverts 965e106f24
Unfortunately, this caused breakage on Windows, and possibly elsewhere,
because parentDir and takeDirectory do not behave the same when there is a
trailing directory separator.
parentDir is less safe than takeDirectory, especially when working
with relative FilePaths. It's really only useful in loops that
want to terminate at /
This commit was sponsored by Audric SCHILTKNECHT.
Now `git annex info $remote` shows info specific to the type of the remote,
for example, it shows the rsync url.
Remote types that support encryption or chunking also include that in their
info.
This commit was sponsored by Ævar Arnfjörð Bjarmason.
encryptionSetup must be called before setRemoteCredPair. Otherwise,
the RemoteConfig doesn't have the cipher in it, and so no cipher is used to
encrypt the embedded creds.
This is a security fix for non-shared encryption methods!
For encryption=shared, there's no security problem, just an
inconsistentency in whether the embedded creds are encrypted.
This is very important to get right, so used some types to help ensure that
setRemoteCredPair is only run after encryptionSetup. Note that the external
special remote bypasses the type safety, since creds can be set after the
initial remote config, if the external special remote program requests it.
Also note that IA remotes never use encryption, so encryptionSetup is not
run for them at all, and again the type safety is bypassed.
This leaves two open questions:
1. What to do about S3 and glacier remotes that were set up
using encryption=pubkey/hybrid with embedcreds?
Such a git repo has a security hole embedded in it, and this needs to be
communicated to the user. Is the changelog enough?
2. enableremote won't work in such a repo, because git-annex will
try to decrypt the embedded creds, which are not encrypted, so fails.
This needs to be dealt with, especially for ecryption=shared repos,
which are not really broken, just inconsistently configured.
Noticing that problem for encryption=shared is what led to commit
fbdeeeed5f, which tried to
fix the problem by not decrypting the embedded creds.
This commit was sponsored by Josh Taylor.
Added a mkUnavailable method, which a Remote can use to generate a version
of itself that is not available. Implemented for several, but not yet all
remotes.
This allows testing that checkPresent properly throws an exceptions when
it cannot check if a key is present or not. It also allows testing that the
other methods don't throw exceptions in these circumstances.
This immediately found several bugs, which this commit also fixes!
* git remotes using ssh accidentially had checkPresent return
an exception, rather than throwing it
* The chunking code accidentially returned False rather than
propigating an exception when there were no chunks and
checkPresent threw an exception for the non-chunked key.
This commit was sponsored by Carlo Matteo Capocasa.
This will allow special remotes to eg, open a http connection and reuse it,
while checking if chunks are present, or removing chunks.
S3 and WebDAV both need this to support chunks with reasonable speed.
Note that a special remote might want to cache a http connection across
multiple requests. A simple case of this is that CheckPresent is typically
called before Store or Remove. A remote using this interface can certianly
use a Preparer that eg, uses a MVar to cache a http connection.
However, it's up to the remote to then deal with things like stale or
stalled http connections when eg, doing a series of downloads from a remote
and other places. There could be long delays between calls to a remote,
which could lead to eg, http connection stalls; the machine might even
move to a new network, etc.
It might be nice to improve this interface later to allow
the simple case without needing to handle the full complex case.
One way to do it would be to have a `Transaction SpecialRemote cache`,
where SpecialRemote contains methods for Storer, Retriever, Remover, and
CheckPresent, that all expect to be passed a `cache`.
I tend to prefer moving toward explicit exception handling, not away from
it, but in this case, I think there are good reasons to let checkPresent
throw exceptions:
1. They can all be caught in one place (Remote.hasKey), and we know
every possible exception is caught there now, which we didn't before.
2. It simplified the code of the Remotes. I think it makes sense for
Remotes to be able to be implemented without needing to worry about
catching exceptions inside them. (Mostly.)
3. Types.StoreRetrieve.Preparer can only work on things that return a
Bool, which all the other relevant remote methods already did.
I do not see a good way to generalize that type; my previous attempts
failed miserably.
