Fixes updating git index file after getting an unlocked file when
annex.stalldetection is set.
The transferrer may want to send additional protocol messages when it's
shut down. Closing the read handle prevented it from doing that, and caused
it to crash rather than cleanly shutting down.
Draining the handle without processing the protocol seemed ok to do,
because anything it outputs is going to be some side message displayed
at shutdown. Displaying those once per transferrer process that is running
seems unncessary.
Sponsored-by: Dartmouth College's DANDI project
When stall detection is enabled, and a transfer is in progress,
it would display a doubled message:
(transfer already in progress, or unable to take transfer lock) (transfer already in progress, or unable to take transfer lock)
That happened because the forward retry decider had a start size of 0,
and an end size of whatever amount of the object the other process had
downloaded. So it incorrectly thought that the transferrer process had
made progress, when it had in fact immediately given up with that
message.
Instead, use the reported value from the progress meter. If a remote
does not report progress, this will mean it doesn't forward retry, in a
situation where it used to. But most remotes do report progress, and any
remote that does not can be fixed to, by using watchFileSize when
downloading. Also, some remotes might preallocate the temp file (eg
bittorrent), so relying on statting its size at this level to get
progress is dubious.
The same change was made to Annex/Transfer.hs, although only
Annex/TransferrerPool.hs needed to be changed to avoid the duplicate
message.
(An alternate fix would have been to start the retry decider with the
size of the object file before downloading begins, rather than 0.)
Sponsored-by: Brett Eisenberg on Patreon
This uses a DebugSelector, rather than debug levels, which will allow
for a later option like --debug-from=Process to only
see debuging about running processes.
The module name that contains the thing being debugged is used as the
DebugSelector (in most cases; does not need to be a hard and fast rule).
Debug calls were changed to add that. hslogger did not display
that first parameter to debugM, but the DebugSelector does get
displayed.
Also fastDebug will allow doing debugging in places that are used in
tight loops, with the DebugSelector coming from the Annex Reader
essentially for free. Not done yet.
Values in AnnexRead can be read more efficiently, without MVar overhead.
Only a few things have been moved into there, and the performance
increase so far is not likely to be noticable.
This is groundwork for putting more stuff in there, particularly a value
that indicates if debugging is enabled.
The obvious next step is to change option parsing to not run in the
Annex monad to set values in AnnexState, and instead return a pure value
that gets stored in AnnexRead.
annex.stalldetection can now be set to "true" to make git-annex do
automatic stall detection when it detects a remote is updating its transfer
progress consistently enough.
This commit was sponsored by Luke Shumaker on Patreon.
git -c was already propagated via environment, but need this for
consistency.
Also, notice it does not use gitAnnexChildProcess to run the
transferrer. So nothing is done about avoid it taking the
pid lock. It's possible that the caller is already doing something that
took the pid lock, and if so, the transferrer will certianly fail,
since it needs to take the pid lock too. This may prevent combining
annex.stalldetection with annex.pidlock, but I have not verified it's
really a problem. If it was, it seems git-annex would have to take
the pid lock when starting a transferrer, and hold it until shutdown,
or would need to take pid lock when starting to use a transferrer,
and hold it until done with a transfer and then drop it. The latter
would require starting the transferrer with pid locking disabled for the
child process, so assumes that the transferrer does not do anyting that
needs locking when not running a transfer.
When fully stalled, the progress bar doesn't update, so waiting on a
MVar would block forever. There's no need to wait anyway, just wake up
after sleeping the configured period and check the current value.
Luckily Viasat makes it really easy for me to notice this kind of
mistake, by stalling long TCP connections frequently.
Done on unix, could not implement it on windows quite.
The signal library gets part of the way needed for windows.
But I had to open https://github.com/pmlodawski/signal/issues/1 because
it lacks raiseSignal.
Also, I don't know what the equivilant of getProcessGroupIDOf is on
windows. And System.Process does not provide a way to send any signal to
a process group except for SIGINT.
This commit was sponsored by Boyd Stephen Smith Jr. on Patreon.
Rather than using Read/Show, which would force me to preserve data types
into the future.
I considered just deriving json and sending that, but I don't much like
deriving json with data types that have named constructors (like Key
does) because again it locks in data type details.
So instead, used SimpleProtocol, with a fairly complex and unreadable
protocol. But it is as efficient as the p2p protocol at least, and as
future proof.
(Writing my own custom json instances would have worked but I thought
of it too late and don't want to do all the work twice. The only real
benefit might be that aeson could be faster.)
Note that, when a new protocol request type is added later, git-annex
trying to use it will cause the git-annex transferrer to display a
protocol error message. That seems ok; it would only happen if a new
git-annex found an old version of itself in PATH or the program
file. So it's unlikely, and all it can do anyway is display an error.
(The error message could perhaps be improved..)
This commit was sponsored by Jack Hill on Patreon.
Doing this at shutdown is not very important at all, but I do like to
make sure that when git-annex allocates a resource, it later cleans it
up.
More importantly, stopCoProcesses is used in eg, Remote.Git in a
situation where it needs to stop long-running processes like these.
This is to avoid breakage when upgrading or downgrading git-annex with a
process running that uses the interface. It's better to keep the
compatability code for a few years than worry about such breakage.
This commit was sponsored by Brett Eisenberg on Patreon.
New config annex.stalldetection, remote.name.annex-stalldetection, which
can be used to deal with remotes that stall during transfers, or are
sometimes too slow to want to use.
This commit was sponsored by Luke Shumaker on Patreon.
There is redundant code in the assistant that does the same thing,
but that code uses a PID, not a ProcessHandle, and gets the PID from,
apparently, the TransferInfo transferPid (although I can't seem to find
where that gets set on non-windows).
Seems to work! Even progress bars. Have not tested prompting or various
error message displays yet.
transferkeys had to be made to operate in different modes for the
Assistant and Annex monads. A bit ugly, but it did relegate that
really ugly Database.Keys.closeDb in transferkeys to only the assistant
code path.
This commit was sponsored by Noam Kremen.
This old code will now be useful for git-annex beyond the assistant.
git-annex won't use the CheckTransferrer part, and won't run transferkeys
as a batch process, and will want withTransferrer to not shut down
transferkeys processes. Still, the rest of this is a good fit for what I
need now.
Also removed some dead code, and simplified a little bit.
This commit was sponsored by Mark Reidenbach on Patreon.
2020-12-07 12:50:48 -04:00
Renamed from Assistant/TransferrerPool.hs (Browse further)
