In c6632ee5c8, it actually only handled
uploading objects to a shared repository. To avoid verification when
downloading objects from a shared repository, was a lot harder.
On the plus side, if the process of downloading a file from a remote
is able to verify its content on the side, the remote can indicate this
now, and avoid the extra post-download verification.
As of yet, I don't have any remotes (except Git) using this ability.
Some more work would be needed to support it in special remotes.
It would make sense for tahoe to implicitly verify things downloaded from it;
as long as you trust your tahoe server (which typically runs locally),
there's cryptographic integrity. OTOH, despite bup being based on shas,
a bup repo under an attacker's control could have the git ref used for an
object changed, and so a bup repo shouldn't implicitly verify. Indeed,
tahoe seems unique in being trustworthy enough to implicitly verify.
When gpg.program is configured, it's used to get the command to run for
gpg. Useful on systems that have only a gpg2 command or want to use it
instead of the gpg command.
This only makes sense for public repos, that are not chunked, so
that there's a 1:1 from Key in the git-annex repo to file on the remote.
Rather than making every remote implementation deal with that, just disable
whereisKey when it doesn't make sense.
"checkPresent baser" was wrong; the baser has a dummy checkPresent action
not the real one. So, to fix this, we need to call preparecheckpresent to
get a checkpresent action that can be used to check if chunks are present.
Note that, for remotes like S3, this means that the preparer is run,
which opens a S3 handle, that will be used for each checkpresent of a
chunk. That's a good thing; if we're resuming an upload that's already many
chunks in, it'll reuse that same http connection for each chunk it checks.
Still, it's not a perfectly ideal thing, since this is a different http
connection that the one that will be used to upload chunks. It would be
nice to improve the API so that both use the same http connection.
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.
Found these with:
git grep "^ " $(find -type f -name \*.hs) |grep -v ': where'
Unfortunately there is some inline hamlet that cannot use tabs for
indentation.
Also, Assistant/WebApp/Bootstrap3.hs is a copy of a module and so I'm
leaving it as-is.
This fixes all instances of " \t" in the code base. Most common case
seems to be after a "where" line; probably vim copied the two space layout
of that line.
Done as a background task while listening to episode 2 of the Type Theory
podcast.
Removed old extensible-exceptions, only needed for very old ghc.
Made webdav use Utility.Exception, to work after some changes in DAV's
exception handling.
Removed Annex.Exception. Mostly this was trivial, but note that
tryAnnex is replaced with tryNonAsync and catchAnnex replaced with
catchNonAsync. In theory that could be a behavior change, since the former
caught all exceptions, and the latter don't catch async exceptions.
However, in practice, nothing in the Annex monad uses async exceptions.
Grepping for throwTo and killThread only find stuff in the assistant,
which does not seem related.
Command.Add.undo is changed to accept a SomeException, and things
that use it for rollback now catch non-async exceptions, rather than
only IOExceptions.
Reusing http connection when operating on chunks is not done yet,
I had to submit some patches to DAV to support that. However, this is no
slower than old-style chunking was.
Note that it's a fileRetriever and a fileStorer, despite DAV using
bytestrings that would allow streaming. As a result, upload/download of
encrypted files is made a bit more expensive, since it spools them to temp
files. This was needed to get the progress meters to work.
There are probably ways to avoid that.. But it turns out that the current
DAV interface buffers the whole file content in memory, and I have
sent in a patch to DAV to improve its interfaces. Using the new interfaces,
it's certainly going to need to be a fileStorer, in order to read the file
size from the file (getting the size of a bytestring would destroy
laziness). It should be possible to use the new interface to make it be a
byteRetriever, so I'll change that when I get to it.
This commit was sponsored by Andreas Olsson.
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.
Pass subcommand as a regular param, which allows passing git parameters
like -c before it. This was already done in the pipeing set of functions,
but not the command running set.
Many functions took the repo as their first parameter. Changing it
consistently to be the last parameter allows doing some useful things with
currying, that reduce boilerplate.
In particular, g <- gitRepo is almost never needed now, instead
use inRepo to run an IO action in the repo, and fromRepo to get
a value from the repo.
This also provides more opportunities to use monadic and applicative
combinators.
Avoid ever using read to parse a non-haskell formatted input string.
show :: Key is arguably still show abuse, but displaying Keys as filenames
is just too useful to give up.
