The vspd Run func is now blocking and returns when its provided context
is cancelled. This means it is invoked/canceled in the same way as the
webapi Run func.
webapi is now created in the main run func rather than within vspd,
further decoupling these components.
The server will shutdown cleanly even if the passed context is already
canceled, so there is no need to pass a new context and blindly guess at
how long the server may need to stop.
Exporting this struct is a step towards breaking up the Start func into
a New func and Run func, enabling calling code to use:
api := webapi.New()
api.Run()
WebAPI is a more suitable name than server because it matches the
package name, and also it helps to distinguish WebAPI from the HTTP
server it uses internally (ie. webapi.server rather than server.server).
It's generally good practice to first create everything that can fail
and then create the final instance at once with the results versus doing
it piecemeal.
Piecemeal creation is typically more error prone and, while not a huge
concern here, it also ends up needlessly creating objects that are just
thrown away in the event of a later error.
Storing references to the database/dcrd/dcrwallet clients inside the
cache struct means they don't need to be passed in every time the cache
is updated.
Any tasks deferred in the main func will not execute if os.Exit is
called. Moving application logic down into a new func which is called by
main works around this limitation.
vspd runs some tasks on startup - database consistency checks, catching
up with missed blocks, etc. If a shutdown is requested while these tasks
are running, vspd should stop immediately rather than continuing to
start the web API server and other background tasks.
The more verbose name was helpful in the past when some code was
handling more than one context, however that is no longer the case due
to refactoring so reverting to the more concise name makes sense.
Using a single select loop for background tasks removes a lot of
duplicated boilerplate code and helps to simplify shutdown logic. This
does reduce the amount of things which can run in parallel, but that
isn't of concern for vspd. The web server still runs in its own
goroutine so its responsiveness won't be affected.
Any tickets in the database which are currently revoked should be
updated to either expired or missed.
This is achieved with a heuristic based on the expiry height and
revoke height of the tickets. It is not guaranteed to be 100% correct
but should be pretty close.
The web api is not yet updated to reflect this change, missed/expired
tickets will continue to be counted as revoked.
Use dcrd and GCS filters to find voted/revoked tickets rather than using
the dcrwallet TicketInfo RPC.
Using TicketInfo was a bit flakey because wallets do not always
correctly detect votes/revokes, and as a result VSP admins may notice
that with this change vspd detects some historic voted/revoked tickets
which TicketInfo never detected.
Simnet params were added in the very first commit of vspd purely because
of copy/pasting from another project.
vspd has never actually been tested on simnet, so its possible
(probable) that it won't even operate correctly without additional dev
work. If we want simnet to be a properly supported network it can be
re-added and tested in the future.
Some of these cover points which have recently been highlighted in
reviews, such as contexts contained in structs, slices initialized with
zero length, and periods missing from the end of comments.
