Previously RPC server shutdown procedure listened to the execution
channel and stopped at the first element that arrived in the queue. This
could lead to the following problems:
* stopper could steal the execution result from subscriber
* stopper didn't wait for other subscription actions to complete
Add dedicated channel to `Server` for subscription routine. Close the
channel on `handleSubEvents` return and wait for signal in `Shutdown`.
Signed-off-by: Leonard Lyubich <leonard@morphbits.io>
Previously RPC server could never be shut down completely due to
some start precondition failure (in particular, inability to serve HTTP
on any configured endpoint). The problem was caused by next facts:
* start method ran subscription routine after HTTP init succeeded only
* stop method blocked waiting for the subscription routine to return
Run `handleSubEvents` routine on fresh `Start` unconditionally. With
this change, `Shutdown` method won't produce deadlock since
`handleSubEvents` closes wait channel.
Refs #2896.
Signed-off-by: Leonard Lyubich <leonard@morphbits.io>
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.
According to docs, `Server` uses provided error channel only to write
encountered error to it. In this case, there is no need to accept rw
channel to create `Server` instance. Strengthening the type to
write-only will allow the caller to ensure control of reading errors
from the provided channel.
The change is backward compatible since any `chan` is `chan<-`.
Signed-off-by: Leonard Lyubich <ctulhurider@gmail.com>
We have both from and to here, so technically we can either drop the neg/neg
trick from the processTokenTransfer() or drop one field from the structure
(the other side is a part of the key). Drop the field since this can make the
DB a bit more compact. Change Amount to be a pointer along the way since
that's the "native" thing for big.Int, we've used non-pointer field
specifically to avoid Neg/Neg problems, but it looks like this is not
necessary.
This structure is only used by the RPC server and I doubt anyone uses it via
the *Blockchain.
And include some node-specific configurations there with backwards
compatibility. Note that in the future we'll remove Ledger's
fields from the ProtocolConfiguration and it'll be possible to access them in
Blockchain directly (not via .Ledger).
The other option tried was using two configuration types separately, but that
incurs more changes to the codebase, single structure that behaves almost like
the old one is better for backwards compatibility.
Fixes#2676.
There are no changes visible from the user side (at least for those
users who doesn't put Prometheus's or pprof's port in quotes), just
internal refactoring. From now and on, BasicService configuration is
used by RPC server config, TLS for RPC server, pprof and Prometheus.
It's more generic and convenient than MillisecondsPerBlock. This setting is
made in backwards-compatible fashion, but it'll override SecondsPerBlock if
both are used. Configurations are specifically not changed here, it's
important to check compatibility.
Fixes#2675.
Blockchain's subscriptions, unsubscriptions and notifications are
handled by a single notificationDispatcher routine. Thus, on attempt
to send the subsequent event to Blockchain's subscribers, dispatcher
can't handle subscriptions\unsubscriptions. Make subscription and
unsubscription to be a non-blocking operation for blockchain on the
server side, otherwise it may cause the dispatcher locks.
To achieve this, use a separate lock for those code that make calls
to blockchain's subscription API and for subscription counters on
the server side.
calculatenetworkfee MUST calculate complete proper network fee, if we have
some extensions enabled and some attributes should be paid for that they're a
part of the equation too.
We're dealing with a transaction here and it can't be decoded successfully
unless it has an appropriate number of witness scripts (matching the number of
signers) with appropriate hashes (matching signers). So this iterations make
no sense at all, we know exactly where to look for the
verification/invocation scripts.
Blockchain's notificationDispatcher sends events to channels and these
channels must be read from. Unfortunately, regular service shutdown procedure
does unsubscription first (outside of the read loop) and only then drains the
channel. While it waits for unsubscription request to be accepted
notificationDispatcher can try pushing more data into the same channel which
will lead to a deadlock. Reading in the same method solves this, any number of
events can be pushed until unsub channel accepts the data.
Which allows to enable/disable the service, change nodes, keys and other
settings. Unfortunately, atomic.Value doesn't allow Store(nil), so we have to
store a pointer there that can point to nil interface.
It's not an ideal solution, but at least it solves the problem for
now. Caveats:
* consensus only needs one method, so it's mirrored to Blockchain
* rpcsrv uses core.* definition of the StateRoot (so technically it might as
well not have an internal Ledger), but it uses core already unfortunately
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
