This is horrible old code and ghc has started to warn about head and
tail. Rewrote it to avoid all partial functions except !! and guarded
uses of !! with length checks.
Its library stack is too old, and while lts-12.14 does include an old
version of servant, some libraries like http-client have been bumped up
from the lts to support eg http-client-restricted. So a newer servant
would be needed, which would lead to many more upgrades.
There might be a dependency set that works, but I have not been able to
find it so far. stack solver also failed to find one.
Primarily because Windows needs a dependency bump to get stm-2.5.1
for Servant build flag.
This includes Win32-2.13.4.0 and aws-0.24 which adds some features
that windows had been missing out on as well.
Lots of warnings about head and tail will need to eventually be
addressed. Of course AFAIK the uses of it in git-annex are all safe.
For writeTMVar. Would be possible to rewrite to use something else, but
I don't want to. Might be possible to write a writeTMVar that works with
the old version of stm.
While usually uploading to a special remote does not verify the content,
the content in a repository is assumed to be valid, and there is no trust
boundary. But with a proxied special remote, there may be users who are
allowed to store objects, but are not really trusted.
Another way to look at this is it's the equivilant of git-annex-shell
checking the hash of received data, which it does (see StoreContent
implementation).
4f3ae96666 caused a hang in GET,
which git-annex testremote could reliably cause.
The problem is that closing both P2P handles before waiting on the
asyncworker prevents all the DATA from getting sent.
The solution is to only close the P2P handles early when the
P2PConnection is being closed. When it's being released, let the
asyncworker finish. closeP2PConnection is called in GET when it was
unable to send all data, and in PUT when it did not receive all the
data, and in both cases closing the P2P handles early is ok.
An interrupted PUT to cluster that has a node that is a special remote
over http left open the connection to the cluster, so the next request
opens another one. So did an interrupted PUT directly to the proxied
special remote over http.
proxySpecialRemote was stuck waiting for all the DATA. Its connection
remained open so it kept waiting.
In servePut, checktooshort handles closing the P2P connection
when too short a data is received from PUT. But, checktooshort was only
called after the protoaction, which is what runs the proxy, which is
what was getting stuck. Modified it to run as a background thread,
which waits for the tooshortv to be written to, which gather always does
once it gets to the end of the data received from the http client.
That makes proxyConnection's releaseconn run once all data is received
from the http client. Made it close the connection handles before
waiting on the asyncworker thread. This lets proxySpecialRemote finish
processing any data from the handle, and then it will give up,
more or less cleanly, if it didn't receive enough data.
I say "more or less cleanly" because with both sides of the P2P
connection taken down, some protocol unhappyness results. Which can lead
to some ugly debug messages. But also can cause the asyncworker thread
to throw an exception. So made withP2PConnections not crash when it
receives an exception from releaseconn.
This did have a small change to the behavior of an interrupted PUT when
proxying to a regular remote. proxyConnection has a protoerrorhandler
that closes the proxy connection on a protocol error. But the proxy
connection is also closed by checktooshort when it closes the P2P
connection. Closing the same proxy connection twice is not a problem,
it just results in duplicated debug messages about it.
