lnd+channeldb: add graph cache option to channeldb

With this commit we forward the config option for disabling the channel
graph cache as a boolean to the channeldb. But we invert its meaning to
make the flag easier to understand.

channeldb/db.go

@@ -291,6 +291,7 @@ func CreateWithBackend(backend kvdb.Backend, modifiers ...OptionModifier) (*DB,
 	chanDB.graph, err = NewChannelGraph(
 		backend, opts.RejectCacheSize, opts.ChannelCacheSize,
 		opts.BatchCommitInterval, opts.PreAllocCacheNumNodes,
+		opts.UseGraphCache,
 	)
 	if err != nil {
 		return nil, err

channeldb/graph.go

@@ -188,8 +188,8 @@ type ChannelGraph struct {
 // NewChannelGraph allocates a new ChannelGraph backed by a DB instance. The
 // returned instance has its own unique reject cache and channel cache.
 func NewChannelGraph(db kvdb.Backend, rejectCacheSize, chanCacheSize int,
-	batchCommitInterval time.Duration,
-	preAllocCacheNumNodes int) (*ChannelGraph, error) {
+	batchCommitInterval time.Duration, preAllocCacheNumNodes int,
+	useGraphCache bool) (*ChannelGraph, error) {
 
 	if err := initChannelGraph(db); err != nil {
 		return nil, err

channeldb/graph_test.go

@@ -77,6 +77,7 @@ func MakeTestGraph(modifiers ...OptionModifier) (*ChannelGraph, func(), error) {
 	graph, err := NewChannelGraph(
 		backend, opts.RejectCacheSize, opts.ChannelCacheSize,
 		opts.BatchCommitInterval, opts.PreAllocCacheNumNodes,
+		true,
 	)
 	if err != nil {
 		backendCleanup()

channeldb/options.go

@@ -45,6 +45,11 @@ type Options struct {
 	// graph cache, so we can pre-allocate the map accordingly.
 	PreAllocCacheNumNodes int
 
+	// UseGraphCache denotes whether the in-memory graph cache should be
+	// used or a fallback version that uses the underlying database for
+	// path finding.
+	UseGraphCache bool
+
 	// clock is the time source used by the database.
 	clock clock.Clock
 
@@ -65,6 +70,7 @@ func DefaultOptions() Options {
 		RejectCacheSize:       DefaultRejectCacheSize,
 		ChannelCacheSize:      DefaultChannelCacheSize,
 		PreAllocCacheNumNodes: DefaultPreAllocCacheNumNodes,
+		UseGraphCache:         true,
 		clock:                 clock.NewDefaultClock(),
 	}
 }
@@ -93,6 +99,13 @@ func OptionSetPreAllocCacheNumNodes(n int) OptionModifier {
 	}
 }
 
+// OptionSetUseGraphCache sets the UseGraphCache option to the given value.
+func OptionSetUseGraphCache(use bool) OptionModifier {
+	return func(o *Options) {
+		o.UseGraphCache = use
+	}
+}
+
 // OptionSetSyncFreelist allows the database to sync its freelist.
 func OptionSetSyncFreelist(b bool) OptionModifier {
 	return func(o *Options) {

config_builder.go

@@ -847,6 +847,7 @@ func (d *DefaultDatabaseBuilder) BuildDatabase(
 		channeldb.OptionSetChannelCacheSize(cfg.Caches.ChannelCacheSize),
 		channeldb.OptionSetBatchCommitInterval(cfg.DB.BatchCommitInterval),
 		channeldb.OptionDryRunMigration(cfg.DryRunMigration),
+		channeldb.OptionSetUseGraphCache(!cfg.DB.NoGraphCache),
 	}
 
 	// We want to pre-allocate the channel graph cache according to what we

routing/pathfind_test.go

@@ -173,6 +173,7 @@ func makeTestGraph() (*channeldb.ChannelGraph, kvdb.Backend, func(), error) {
 	graph, err := channeldb.NewChannelGraph(
 		backend, opts.RejectCacheSize, opts.ChannelCacheSize,
 		opts.BatchCommitInterval, opts.PreAllocCacheNumNodes,
+		true,
 	)
 	if err != nil {
 		cleanUp()