I hope this will be easier to reason about, and less buggy. It was
certianly easier to write!
An immediate benefit is that with a traversable queue of push requests to
select from, the threads can be a lot fairer about choosing which client to
service next.
This will avoid losing any messages received from 1 client when a push
involving another client is running.
Additionally, the handling of push initiation is improved,
it's no longer allowed to run multiples of the same type of push to
the same client.
Still stalls sometimes :(
Observed: With 2 xmpp clients, one would sometimes stop responding
to CanPush messages. Often it was in the middle of a receive-pack
of its own (or was waiting for a failed one to time out).
Now these are always immediately responded to, which is fine; the point
of CanPush is to find out if there's another client out there that's
interested in our push.
Also, in queueNetPushMessage, queue push initiation messages when
we're already running the side of the push they would initiate.
Before, these messages were sent into the netMessagesPush channel,
which was wrong. The xmpp send-pack and receive-pack code discarded
such messages.
This still doesn't make XMPP push 100% robust. In testing, I am seeing
it sometimes try to run two send-packs, or two receive-packs at once
to the same client (probably because the client sent two requests).
Also, I'm seeing rather a lot of cases where it stalls out until it
runs into the 120 second timeout and cancels a push.
And finally, there seems to be a bug in runPush. I have logs that
show it running its setup action, but never its cleanup action.
How is this possible given its use of E.bracket? Either some exception
is finding its way through, or the action somehow stalls forever.
When this happens, one of the 2 clients stops syncing.
(Except for the actual streaming of receive-pack through XMPP, which
can only run once we've gotten an appropriate uuid in a push initiation
message.)
Pushes are now only initiated when the initiation message comes from a
known uuid. This allows multiple distinct repositories to use the same xmpp
address.
Note: This probably breaks initial push after xmpp pairing, because at that
point we may not know about the paired uuid, and so reject the push from
it. It won't break in simple cases, because the annex-uuid of the remote
is checked. However, when there are multiple clients behind a single xmpp
address, only uuid of the first is recorded in annex-uuid, and so any
pushes from the others will be rejected (unless the first remote pushes their
uuids to us beforehand.
If an add failed, we should lose the KeySource, since it, presumably,
differs due to a change that was made to the file.
(The locked down file is already deleted.)
Making this a tset of lists of Changes, rather than a tset of Changes
makes refilling it, in batch mode, much more efficient. Rather than needing
to add every Change it's collected one at a time, it can add them in one
fast batch operation.
It would be more efficient yet to use a Set, but that would need an Eq
instance for InodeCache.
This cleaned up the code quite a bit; now the committer just looks at the
Change to see if it's a change that needs to have a transfer queued for it.
If I later want to add dropping keys for files that were removed, or
something like that, this should make it straightforward.
This also fixes a bug. In direct mode, moving a file out of an archive
directory failed to start a transfer to get its content. The problem
was that the file had not been committed to git yet, and so the transfer
code didn't want to touch it, since fileKey failed to get its key.
Only starting transfers after a commit avoids this problem.
Noticed that, At startup or network reconnect, git push messages were sent,
often before presence info has been gathered, so were not sent to any
buddies.
To fix this, keep track of which buddies have seen such messages,
and when new presence is received from a buddy that has not yet seen it,
resend.
This is done only for push initiation messages, so very little data needs
to be stored.
This fixes the issue mentioned in the last commit.
Turns out just collecting UUID of clients behind a XMPP remote is
insufficient (although I should probably still do it for other reasons),
because a single remote repo might be connected via both XMPP and local
pairing. So a way is needed to know when a push was received from any
client using a given XMPP remote over XMPP, as opposed to via ssh.
Make manualPull send push requests over XMPP.
When reconnecting with remotes, those that are XMPP remotes cannot
immediately be pulled from and scanned, so instead maintain a set of
(probably) desynced remotes, and put XMPP remotes on it. (This set could be
used in other ways later, if we can detect we're out of sync with other
types of remotes.)
The merger handles detecting when a XMPP push is received from a desynced
remote, and triggers a scan then, if they have in fact diverged.
This has one known bug: A single XMPP remote can have multiple clients
behind it. When this happens, only the UUID of one client is recorded
as the UUID of the XMPP remote. Pushes from the other XMPP clients will not
trigger a scan. If the client whose UUID is expected responds to the push
request, it'll work, but when that client is offline, we're SOL.
Noticed that when pairing, sometimes both sides start to push, and the other
side sends a PushRequest, and the two deadlock, neither doing anything.
(Timeout eventually breaks this.) So, let both run at the same time.
My reasoning is that StartingPush could be received after another push
starts being received, and it would be better to respond to it afterwards
than not.
It might even work, although nothing yet triggers XMPP pushes.
Also added a set of deferred push messages. Only one push can run at a
time, and unrelated push messages get deferred. The set will never grow
very large, because it only puts two types of messages in there, that
can only vary in the client doing the push.
