We do this in preparation for moving channel cache population logic out
of the constructor and into the Start method. We also will later on
(when topology subscription is moved to the ChannelGraph), have a
goroutine that will need to be kicked off and stopped.
Here, we move the graph cache writes for AddLightningNode,
DeleteLightningNode, AddChannelEdge and MarkEdgeLive to the
ChannelGraph. Since these are writes, the cache is only updated if the
DB write is successful.
This commit moves the graph cache checks for FetchNodeFeatures,
ForEachNodeDirectedChannel, GraphSession and ForEachNodeCached from the
KVStore to the ChannelGraph. Since the ChannelGraph is currently just a
pass-through for any of the KVStore methods, all that needs to be done
for calls to go via the ChannelGraph instead directly to the KVStore is
for the ChannelGraph to go and implement those methods.
In this commit, we let the ChannelGraph be responsible for populating
the graphCache and then passing it to the KVStore. This is a first step
in moving the graphCache completely out of the KVStore layer.
And use this struct to pass NewChannelGraph anything it needs to be able
to init the KVStore that it houses. This will allow us to add
ChannelGraph specific options.
Since we have renamed a file housing some very old code, the linter has
now run on all this code for the first time. So we gotta do some
clean-up work here to make it happy.
In this commit, we rename the existing ChannelGraph struct to KVStore to
better reflect its responsibilities as the CRUD layer. We then introduce
a new ChannelGraph struct which will eventually be the layer above the
CRUD layer in which we will handle cacheing and topology subscriptions.
For now, however, it houses only the KVStore. This means that all calls
to the KVStore will now go through this layer of indirection first. This
will allow us to slowly move the graph Cache management out of the
KVStore and into the new ChannelGraph layer.
We introduce the new ChannelGraph and rename the old one in the same
commit so that all existing call-sites don't need to change at all :)
Rename it to kv_store.go so that we can re-use the graph.go file name
later on. We will use it to house the _new_ ChannelGraph when the
existing ChannelGraph is renamed to more clearly reflect its
responsibilities as the CRUD layer.
