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0a2ccfc52b
This commit partially reverts bf27d05a.
To avoid creating multiple database transactions during a single path
finding operation, we create an explicit transaction when the cached
graph is instantiated.
We cache the source node to avoid needing to look that up for every path
finding session.
The database transaction will be nil in case of the in-memory graph.
89 lines
2.4 KiB
Go
89 lines
2.4 KiB
Go
package routing
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import (
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"github.com/lightningnetwork/lnd/channeldb"
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"github.com/lightningnetwork/lnd/kvdb"
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"github.com/lightningnetwork/lnd/lnwire"
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"github.com/lightningnetwork/lnd/routing/route"
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)
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// routingGraph is an abstract interface that provides information about nodes
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// and edges to pathfinding.
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type routingGraph interface {
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// forEachNodeChannel calls the callback for every channel of the given
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// node.
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forEachNodeChannel(nodePub route.Vertex,
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cb func(channel *channeldb.DirectedChannel) error) error
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// sourceNode returns the source node of the graph.
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sourceNode() route.Vertex
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// fetchNodeFeatures returns the features of the given node.
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fetchNodeFeatures(nodePub route.Vertex) (*lnwire.FeatureVector, error)
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}
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// CachedGraph is a routingGraph implementation that retrieves from the
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// database.
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type CachedGraph struct {
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graph *channeldb.ChannelGraph
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tx kvdb.RTx
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source route.Vertex
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}
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// A compile time assertion to make sure CachedGraph implements the routingGraph
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// interface.
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var _ routingGraph = (*CachedGraph)(nil)
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// NewCachedGraph instantiates a new db-connected routing graph. It implicitly
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// instantiates a new read transaction.
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func NewCachedGraph(sourceNode *channeldb.LightningNode,
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graph *channeldb.ChannelGraph) (*CachedGraph, error) {
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tx, err := graph.NewPathFindTx()
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if err != nil {
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return nil, err
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}
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return &CachedGraph{
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graph: graph,
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tx: tx,
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source: sourceNode.PubKeyBytes,
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}, nil
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}
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// close attempts to close the underlying db transaction. This is a no-op in
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// case the underlying graph uses an in-memory cache.
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func (g *CachedGraph) close() error {
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if g.tx == nil {
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return nil
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}
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return g.tx.Rollback()
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}
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// forEachNodeChannel calls the callback for every channel of the given node.
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//
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// NOTE: Part of the routingGraph interface.
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func (g *CachedGraph) forEachNodeChannel(nodePub route.Vertex,
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cb func(channel *channeldb.DirectedChannel) error) error {
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return g.graph.ForEachNodeChannel(g.tx, nodePub, cb)
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}
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// sourceNode returns the source node of the graph.
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//
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// NOTE: Part of the routingGraph interface.
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func (g *CachedGraph) sourceNode() route.Vertex {
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return g.source
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}
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// fetchNodeFeatures returns the features of the given node. If the node is
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// unknown, assume no additional features are supported.
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//
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// NOTE: Part of the routingGraph interface.
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func (g *CachedGraph) fetchNodeFeatures(nodePub route.Vertex) (
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*lnwire.FeatureVector, error) {
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return g.graph.FetchNodeFeatures(nodePub)
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}
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