Checking .gitattributes adds a full minute to a git annex find looking for
files that don't have enough copies. 2:25 increasts to 3:27. I feel this is
too much of a slowdown to justify making it the default. So, exposed two
versions of the preferred content expression, a slow one and a fast but
approximate one.
I'm using the approximate one in the default preferred content expressions
to avoid slowing down the assistant.
* Add numcopiesneeded preferred content expression.
* Client, transfer, incremental backup, and archive repositories
now want to get content that does not yet have enough copies.
This means the asssistant will make copies of files that don't yet
meet the configured numcopies, even to places that would not normally want
the file.
For example, if numcopies is 4, and there are 2 client repos and
2 transfer repos, and 2 removable backup drives, the file will be sent
to both transfer repos in order to make 4 copies. Once a removable drive
get a copy of the file, it will be dropped from one transfer repo or the
other (but not both).
Another example, numcopies is 3 and there is a client that has a backup
removable drive and two small archive repos. Normally once one of the small
archives has a file, it will not be put into the other one. But, to satisfy
numcopies, the assistant will duplicate it into the other small archive
too, if the backup repo is not available to receive the file.
I notice that these examples are fairly unlikely setups .. the old behavior
was not too bad, but it's nice to finally have it really correct.
.. Almost. I have skipped checking the annex.numcopies .gitattributes
out of fear it will be too slow.
This commit was sponsored by Florian Schlegel.
* numcopies: New command, sets global numcopies value that is seen by all
clones of a repository.
* The annex.numcopies git config setting is deprecated. Once the numcopies
command is used to set the global number of copies, any annex.numcopies
git configs will be ignored.
* assistant: Make the prefs page set the global numcopies.
This global numcopies setting is needed to let preferred content
expressions operate on numcopies.
It's also convenient, because typically if you want git-annex to preserve N
copies of files in a repo, you want it to do that no matter which repo it's
running in. Making it global avoids needing to warn the user about gotchas
involving inconsistent annex.numcopies settings.
(See changes to doc/numcopies.mdwn.)
Added a new variety of git-annex branch log file, that holds only 1 value.
Will probably be useful for other stuff later.
This commit was sponsored by Nicolas Pouillard.
Similar to the assistant, this honors any configured preferred content
expressions.
I am not entirely happpy with the implementation. It would be nicer if
the seek function returned a list of actions which included the individual
file gets and copies and drops, rather than the current list of calls to
syncContent. This would allow getting rid of the somewhat reundant display
of "sync file [ok|failed]" after the get/put display.
But, do that, withFilesInGit would need to somehow be able to construct
such a mixed action list. And it would be less efficient than the current
implementation, which is able to reuse several values between eg get and
drop.
Note that currently this does not try to satisfy numcopies when
getting/putting files (numcopies are of course checked when dropping
files!) This makes it like the assistant, and unlike get --auto
and copy --auto, which do duplicate files when numcopies is not yet
satisfied. I don't know if this is the right decision; it only seemed to
make sense to have this parallel the assistant as far as possible to start
with, since I know the assistant works.
This commit was sponsored by Øyvind Andersen Holm.
Known problems:
1. Tries to tahoe start when daemon is already running.
2. If multiple tahoe remotes are set up on the same computer,
they will have the same node.url configured by default,
and this confuses tahoe commands.
This commit was sponsored by LeastAuthority.com
So that remotes that use a persistent network connection are restarted.
A remote might keep open a long duration network connection, and could
fail to deal well with losing the connection. This is particularly a
concern now that we have external special reotes. An external
special remote that is implemented naively might open the connection only
when PREPARE is sent, and if it loses connection, throw errors on each
request that is made.
(Note that the ssh connection caching should not have this problem; if the
long-duration ssh process loses connection, the named pipe is disconnected
and the next ssh attempt will reconnect. Also, XMPP already deals with
disconnection robustly in its own way.)
There's no way for git-annex to know if a lost network connection actually
affects a given remote, which might have a transfer in process. It does not
make sense to force kill the transferkeys process every time the NetWatcher
detects a change. (Especially because the NetWatcher sometimes polls 1
change per hour.)
In any case, the NetWatcher only detects connection to a network, not
disconnection. So if a transfer is in progress over the network, and the
network goes down, that will need to time out on its own.
An alternate approch that was considered is to use a separate transferkeys
process for each remote, and detect when a request fails, and assume that
means that process is in a failing state and restart it. The problem with
that approach is that if a resource is not available and a remote fails
every time, it degrades to starting a new transferkeys process for every
file transfer, which is too expensive.
Instead, this commit only handles the network reconnection case, and restarts
transferkeys only once the network has reconnected and another transfer needs
to be made. So, a transferkeys process will be reused for 1 hour, or until the
next network connection.
----
The NotificationBroadcaster was rewritten to use TMVars rather than MSampleVars,
to allow checking without blocking if a notification has been received.
----
This commit was sponsored by Tobias Brunner.
Noticed that it was possible for add to move a file to .git/annex/objects
and not make the link if the disk was full. This happened because the
location log update failed, and so addLink never got a chance to run.
Running addLink first fixes it; on error it will unwind by moving the file
back to where it was originally.
This adds a http HEAD before the download is done. That was already the
case when the assistant was running, and it seems worth it to avoid filling
up the whole disk, like happened to my server today.
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.
