`makeWsRequest` creates a channel for response and waits for it. If between
creating the channel and starting the reading `select` connection is lost
(`writerDone` channel is closed), nothing reads from the channel and a
deadlock appears. Looking at "done" channels when transferring RPC data
solves the issue. Closes#3530.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Every client's (Un)Subscription call does two things: an RPC call and a
subscription map lock (two of maps currently). If we imagine that there is
one routine that tries to subscribe (A) and one routine that tries to
unsubscribe (B), the following sequence can happen:
0. Current number of subscriptions is X
1. B does an RPC and makes number of subscriptions X-1
2. A does an RPC and makes number of subscriptions X again
3. A holds subscription locks and rewrites client's subscription state
(subscription with ID X now points to a different channel; channel that
was registered by B is lost and is not related to any real subscription
but is still included in the `receivers` map)
4. B holds subscription locks and drops subscription X (first, it is an
error and we have just lost a subscription that we think was made
successfully second, we have lost a channel in the `receivers` map, and
no corresponding subscription points to it)
5. X subscription is received by the WS client (in practice it is a new
block, 100ms, quite often to be sure this issue happens every hour), we
range through the receivers, see no corresponding subscription, and
panic.
Closes#3093.
Signed-off-by: Pavel Karpy <carpawell@nspcc.ru>
Revert 5f6c01336c, remove all multierror
related nolint comments and use multierror wrapping instead.
Close#2906.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
New event is to notify the user about header's content by the moment
when block is stored (which happens after block's processing). This is
needed for proper Waiter work.
Closes#2751.
Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>
Add new filter NotaryRequestFilter, support for filtering
NotaryRequestEvents by mempoolevent.Type
(added or removed).
Closes#2425.
Signed-off-by: Ekaterina Pavlova <ekt@morphbits.io>
StateRootInHeader depends on it, so we better immediately return error
if client is not initialised.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
* Rename c.done channel to c.readerDone
* Introduce c.writerDone channel that is closed if the wsWriter's loop
is done
* Make the error returned by makeWsRequests verbose
Signed-off-by: Ayrtat <amper.meter1775@gmail.com>
Regular Client doesn't care much about connections, because HTTP client's Do
method can reuse old ones or create additional ones on the fly. So one request
can fail and the next one easily succeed. WSClient is different, it works via
a single connection and if it breaks, it breaks forever for this
client. Callers will get some error on every request afterwards and it'd be
nice for this error to be the same so that API users could detect
disconnection this way too.
Related to nspcc-dev/neofs-node#2325.
Signed-off-by: Roman Khimov <roman@nspcc.ru>
go.uber.org/atomic deprecated CAS methods in version 1.10 (that introduced
CompareAndSwap), so we need to fix it.
Signed-off-by: Roman Khimov <roman@nspcc.ru>
Close#2894.
It should be noted that the subscriber's channel is being removed from the
list of receivers and closed, but it is still *in the list of subscribers*
and no unsubscription is performed by WSClient. Which means that RPC server
keeps sending notifications to WSClient and WSClient keeps dropping them
(because there's no receiver for this subscription and it's OK, WSClient
can handle this and this behaviour is documented). However, it's still the
caller's duty to call Unsubscribe() method for this subscription.
Signed-off-by: Anna Shaleva <shaleva.ann@nspcc.ru>
The reader is about to exit and it will close legacy c.Notifications, but it
will leave subscription channels at the same time. This is wrong since these
channels will no longer receive any new events, game over.
Signed-off-by: Roman Khimov <roman@nspcc.ru>
wsReader() closes c.done first and then goes over the list of
c.respChannels. Technically this means that any of the two can be taken in
this select.
Signed-off-by: Roman Khimov <roman@nspcc.ru>
Everywhere including examples, external interop APIs, bindings generators
code and in other valuable places. A couple of `interface{}` usages are
intentionally left in the CHANGELOG.md, documentation and tests.
It has a special `requestF` and a special initialization function, but other
than that it's an absolutely regular WSClient. Can be used to call, can be
used to subscribe. Fixes#2909.
Do not block subscribers until the unsubscription request to RPC server
is completed. Otherwise, another notification may be received from the
RPC server which will block the unsubscription process.
At the same time, fix event-based waiter. We must not block the receiver
channel during unsubscription because there's a chance that subsequent
event will be sent by the server. We need to read this event in order not
to block the WSClient's readloop.
1. It's not good for pkg/core to import anything from pkg/neorpc.
2. The type is closely tied to the state package, even though it's not stored
in the DB
