Depends on btcsuite/btcwallet#757.
Pulls in the updated version of btcwallet and walletdb that have the DB
interface enhanced by their own View() and Update() methods with the
reset callback/closure supported out of the box. That way the global
package-level View() and Update() functions now become pure redirects.
Since we're now storing the content of multiple previously distinct
database files in etcd, we want to properly namespace them as not to
provoke any key collisions. We append a sub namespace to the given
global namespace in order to still support multiple lnd nodes using the
same etcd database simultaneously.
Because the btcwallet code uses the legacy walletdb interface we must
assume it is not fully concurrency safe. Therefore we make sure only a
single writer can be active at any given time for the wallet DB backend
when using etcd.
To have all the database backend related code in one place, we finally
also move the initialization of the wallet DB loader option into the
GetBackends() method.
The final database that needs to be made remote compatible is the
watchtower server and client database.
They are handled a bit differently because both of them are not always
active, only when specifically turned on in the config.
Even though the sphinx router's persistent replay log is not crucial in
the operation of lnd as its state can be re-created by creating a new
brontide connection, we want to make lnd fully stateless and therefore
have the option of not storing any state on disk.
The wallet and macaroon databases are the first files that are created
for a new node. When initializing those databases, the parent directory
is created if it does not exist.
With both of the databases now potentially being remote, that code that
creates the parent directory might never be executed and we need to do
that manually when parsing the configuration.
Otherwise we run into an error when we later try to create our default
macaroons in that folder and it doesn't exist.
The macaroon root keys should also be stored to the remote database if a
replicated backend such as etcd is used.
This commit refactors the macaroons service and wallet unlocker to
accept a kvdb backend directly instead of creating the bolt instance
automatically.
This commit gets rid of the concept of a local and remote database when
etcd is used. Instead the same backend is now used for both the
(previously renamed from local and remote DB) graph and channel state
databases.
This will make path finding extremely slow on etcd and will require
further optimizations and possibly a write-through cache for the graph
DB. But this is a requirement for making lnd itself fully stateless.
In order to separate our databases more clearly, we refactor the height
hint cache DB to use a kvdb backend instead of the channel DB instance
directly.
As a preparation to not have a local and remote version of the database
around anymore, we rename the variables into what their actual function
is. In case of the RPC server we even directly use the channel graph
instead of the DB instance. This should allow us to extract the channel
graph into its own, separate database (perhaps with better access
characteristics) in the future.
As a preparation to initialize more than just the channel database on
startup we introduce a new struct that holds a reference to each of our
database instances.
Improve 'ErrReservedValueInvalidated' error string to explain that the
error is triggered by a transaction that would deplete funds reserved for
potential future anchor channel closings (via CPFP)
Add hint that further details can be found in the debug log
Update strings in 'lntest/itest/log_error_whitelist.txt' correspondingly
Since we don't really do anything with the errors we check in the itest
error whitelist but get a lot of failed Travis runs because of it, we
disable the check for the moment.
We bump the version of the healthcheck module to a version that does not
exist. But by doing so we can tag the merge commit of this PR with that
actual version and have everything working. That is faster than merging
the changes to the module, pushing a tag, then bumping the tag in
go.mod.
To reduce the likelyhood of the linter OOMing on the GitHub runner, we
exclude any generated code from being inspected and also tune the golang
garbage collector to be a bit more agressive.
To avoid a naming conflict with etcd, we rename our very generic
rpc.proto to lightning.proto to match the service name that's declared
within. This will break many external tutorials and possibly also our
API docs but the change needs to be done eventually.
As a preparation for the migration to the grpc-gateway/v2 library we
declare each service's REST annotations in its own file. This is
optional in the v1 library but mandatory in v2.
This commit changes missioncontrol's store update from per payment to
every second. Updating the missioncontrol store on every payment caused
gradual slowdown when using etcd.
We also completely eliminate the use of the cursor, further reducing
the performance bottleneck.
This removes a warning in the documentation saying that pruned nodes are
not supported. This is no longer the case as [pruning is supported since
0.13](https://github.com/lightningnetwork/lnd/pull/5154). So instead it
now says pruning is supported and notes the version and implications of
pruning.
