This allows a remote to store a piece of arbitrary state associated with a
key. This is needed to support Tahoe, where the file-cap is calculated from
the data stored in it, and used to retrieve a key later. Glacier also would
be much improved by using this.
GETSTATE and SETSTATE are added to the external special remote protocol.
Note that the state is left as-is even when a key is removed from a remote.
It's up to the remote to decide when it wants to clear the state.
The remote state log, $KEY.log.rmt, is a UUID-based log. However,
rather than using the old UUID-based log format, I created a new variant
of that format. The new varient is more space efficient (since it lacks the
"timestamp=" hack, and easier to parse (and the parser doesn't mess with
whitespace in the value), and avoids compatability cruft in the old one.
This seemed worth cleaning up for these new files, since there could be a
lot of them, while before UUID-based logs were only used for a few log
files at the top of the git-annex branch. The transition code has also
been updated to handle these new UUID-based logs.
This commit was sponsored by Daniel Hofer.
This was unexpectedly difficult because of a depdenency cycle. To parse a
preferred content expression involves several things that need to operate
on the list of remotes. Which needs Remote.External. The only way to avoid
this cycle (I tried breaking it at several points) was to skip parsing the
expression in SETWANTED.
That's sorta ok, because git-annex already has to deal with unparsable
preferred content expressions being stored, in order to handle eg,
upgrades. But I'm still not very happy that I cannot check it.
I feel this is a strong indication that I need to beware of further
bloating the special remote protocol interface.
Changed protocol spec to make SETCONFIG only store it persistently when run
during INITREMOTE. I see no reason to support storing it persistently at
other times, and doing so would unnecessarily complicate the code.
Also, letting that be done would probably result in use for storing data that
doesn't really belong there, and special remote authors who don't
understand how the union merging works would probably be surprised the
results.
That complicated special remote programs, because they had to avoid making
PREPARE fail if some configuration is missing, because the remote might not
be initialized yet. Instead, complicate git-annex slightly by only sending
PREPARE immediately before some other request other than INITREMOTE (or
PREPARE of course).
This is mostly straightforward, but did turn out quite nicely stronly
typed, and with a quite nice automatic tokenization and parsing of received
messages.
Made a few minor changes to the protocol to clear up ambiguities and make
it easier to parse. Note particularly that setting remote configuration
is moved to a separate command, which allows a remote to set arbitrary data.
More complicated, but less asynchronous, which will make it easier for
special remote programs to use it, at the expense of some added complexity
in git-annex.
When starting up the assistant, it'll remind about the current
repository, if it doesn't have checks. And when a removable drive
is plugged in, it will remind if a repository on it lacks checks.
Since that might be annoying, the reminders can be turned off.
This commit was sponsored by Nedialko Andreev.
/!\ It is to be noted that revoking a key does NOT necessarily prevent
the owner of its private part from accessing data on the remote /!\
The only sound use of `keyid-=` is probably to replace a (sub-)key by
another, where the private part of both is owned by the same
person/entity:
git annex enableremote myremote keyid-=2512E3C7 keyid+=788A3F4C
Reference: http://git-annex.branchable.com/bugs/Using_a_revoked_GPG_key/
* Other change introduced by this patch:
New keys now need to be added with option `keyid+=`, and the scheme
specified (upon initremote only) with `encryption=`. The motivation for
this change is to open for new schemes, e.g., strict asymmetric
encryption.
git annex initremote myremote encryption=hybrid keyid=2512E3C7
git annex enableremote myremote keyid+=788A3F4C
Requires git 1.8.4 or newer. When it's installed, a background
git check-ignore process is run, and used to efficiently check ignores
whenever a new file is added.
Thanks to Adam Spiers, for getting the necessary support into git for this.
A complication is what to do about files that are gitignored but have
been checked into git anyway. git commands assume the ignore has been
overridden in this case, and not need any more overriding to commit a
changed version.
However, for the assistant to do the same, it would have to run git ls-files
to check if the ignored file is in git. This is somewhat expensive. Or it
could use the running git-cat-file process to query the file that way,
but that requires transferring the whole file content over a pipe, so it
can be quite expensive too, for files that are not git-annex
symlinks.
Now imagine if the user knows that a file or directory tree will be getting
frequent changes, and doesn't want the assistant to sync it, so gitignores
it. The assistant could overload the system with repeated ls-files checks!
So, I've decided that the assistant will not automatically commit changes
to files that are gitignored. This is a tradeoff. Hopefully it won't be a
problem to adjust .gitignore settings to not ignore files you want the
assistant to autocommit, or to manually git annex add files that are listed
in .gitignore.
(This could be revisited if git-annex gets access to an interface to check
the content of the index w/o forking a git command. This could be libgit2,
or perhaps a separate git cat-file --batch-check process, so it wouldn't
need to ship over the whole file content.)
This commit was sponsored by Francois Marier. Thanks!
