Noticed that Semigroup instance of Map is not suitable to use
for MapLog. For example, it behaved like this:
ghci> parseTrustLog "foo 1 timestamp=10\nfoo 2 timestamp=11" <> parseTrustLog "foo X timestamp=12"
fromList [(UUID "foo",LogEntry {changed = VectorClock 11s, value = SemiTrusted})]
Which was wrong, it lost the newer DeadTrusted value.
Luckily, nothing used that Semigroup when operating on a MapLog. And this
provides a safe instance.
Sponsored-by: Graham Spencer on Patreon
This adds a separate journal, which does not currently get committed to
an index, but is planned to be committed to .git/annex/index-private.
Changes that are regarding a UUID that is private will get written to
this journal, and so will not be published into the git-annex branch.
All log writing should have been made to indicate the UUID it's
regarding, though I've not verified this yet.
Currently, no UUIDs are treated as private yet, a way to configure that
is needed.
The implementation is careful to not add any additional IO work when
privateUUIDsKnown is False. It will skip looking at the private journal
at all. So this should be free, or nearly so, unless the feature is
used. When it is used, all branch reads will be about twice as expensive.
It is very lucky -- or very prudent design -- that Annex.Branch.change
and maybeChange are the only ways to change a file on the branch,
and Annex.Branch.set is only internal use. That let Annex.Branch.get
always yield any private information that has been recorded, without
the risk that Annex.Branch.set might be called, with a non-private UUID,
and end up leaking the private information into the git-annex branch.
And, this relies on the way git-annex union merges the git-annex branch.
When reading a file, there can be a public and a private version, and
they are just concacenated together. That will be handled the same as if
there were two diverged git-annex branches that got union merged.
Especially from borg, where the content identifier logs
all end up being the same identical file!
But also, for other imports, the location tracking logs can,
in some cases, be identical files.
Bonus optimisation: Avoid looking up (and parsing when set)
GIT_ANNEX_VECTOR_CLOCK env var every time a log is written to.
Although the lookup does happen at startup even when no
log will be written now.
This does not change the overall license of the git-annex program, which
was already AGPL due to a number of sources files being AGPL already.
Legally speaking, I'm adding a new license under which these files are
now available; I already released their current contents under the GPL
license. Now they're dual licensed GPL and AGPL. However, I intend
for all my future changes to these files to only be released under the
AGPL license, and I won't be tracking the dual licensing status, so I'm
simply changing the license statement to say it's AGPL.
(In some cases, others wrote parts of the code of a file and released it
under the GPL; but in all cases I have contributed a significant portion
of the code in each file and it's that code that is getting the AGPL
license; the GPL license of other contributors allows combining with
AGPL code.)
There should be some speed gains here, especially for chunk and remote
state logs, which are queried once per key.
Now only old-format uuid-based logs still need to be converted to attoparsec.
Probably not any particular speedup in this, since most of these logs
are not written to often. Possibly chunk log writing is sped up, but
writes to chunk logs are interleaved with expensive data transfers to
remotes, so unlikely to be a noticiable speedup.
Most of the individual logs are not converted yet, only presense logs
have an efficient ByteString Builder implemented so far. The rest
convert to and from String.
Can be used to override the default timestamps used in log files in the
git-annex branch. This is a dangerous environment variable; use with
caution.
Note that this only affects writing to the logs on the git-annex branch.
It is not used for metadata in git commits (other env vars can be set for
that).
There are many other places where timestamps are still used, that don't
get committed to git, but do touch disk. Including regular timestamps
of files, and timestamps embedded in some files in .git/annex/, including
the last fsck timestamp and timestamps in transfer log files.
A good way to find such things in git-annex is to get for getPOSIXTime and
getCurrentTime, although some of the results are of course false positives
that never hit disk (unless git-annex gets swapped out..)
So this commit does NOT necessarily make git-annex comply with some HIPPA
privacy regulations; it's up to the user to determine if they can use it in
a way compliant with such regulations.
Benchmarking: It takes 0.00114 milliseconds to call getEnv
"GIT_ANNEX_VECTOR_CLOCK" when that env var is not set. So, 100 thousand log
files can be written with an added overhead of only 0.114 seconds. That
should be by far swamped by the actual overhead of writing the log files
and making the commit containing them.
This commit was supported by the NSF-funded DataLad project.
I hope this doesn't impact speed much -- it does have to pull out a value
from Annex state every time it accesses the branch now.
The test case I dropped has never caught any problems that I can remember,
and would have been rather difficult to convert.
Slightly tricky as they are not normal UUIDBased logs, but are instead maps
from (uuid, chunksize) to chunkcount.
This commit was sponsored by Frank Thomas.
