lnd.xprv/autopilot/interface.go
Johan T. Halseth cfd237bf1f
autopilot: move determining chanSize from heuristic to agent
Since we want to combine scores from multiple heuristics, things get
complicated if the heuristics report their own individual channel sizes.
Therefore we change the NodeScores interface slightly, letting the agent
specify the wanted channel size, and let the heuristic score the nodes
accordingly.
2019-01-08 10:10:59 +01:00

158 lines
6.2 KiB
Go

package autopilot
import (
"net"
"github.com/btcsuite/btcd/btcec"
"github.com/btcsuite/btcd/wire"
"github.com/btcsuite/btcutil"
"github.com/lightningnetwork/lnd/lnwire"
)
// Node node is an interface which represents n abstract vertex within the
// channel graph. All nodes should have at least a single edge to/from them
// within the graph.
//
// TODO(roasbeef): combine with routing.ChannelGraphSource
type Node interface {
// PubKey is the identity public key of the node. This will be used to
// attempt to target a node for channel opening by the main autopilot
// agent. The key will be returned in serialized compressed format.
PubKey() [33]byte
// Addrs returns a slice of publicly reachable public TCP addresses
// that the peer is known to be listening on.
Addrs() []net.Addr
// ForEachChannel is a higher-order function that will be used to
// iterate through all edges emanating from/to the target node. For
// each active channel, this function should be called with the
// populated ChannelEdge that describes the active channel.
ForEachChannel(func(ChannelEdge) error) error
}
// Channel is a simple struct which contains relevant details of a particular
// channel within the channel graph. The fields in this struct may be used a
// signals for various AttachmentHeuristic implementations.
type Channel struct {
// ChanID is the short channel ID for this channel as defined within
// BOLT-0007.
ChanID lnwire.ShortChannelID
// Capacity is the capacity of the channel expressed in satoshis.
Capacity btcutil.Amount
// FundedAmt is the amount the local node funded into the target
// channel.
//
// TODO(roasbeef): need this?
FundedAmt btcutil.Amount
// Node is the peer that this channel has been established with.
Node NodeID
// TODO(roasbeef): also add other traits?
// * fee, timelock, etc
}
// ChannelEdge is a struct that holds details concerning a channel, but also
// contains a reference to the Node that this channel connects to as a directed
// edge within the graph. The existence of this reference to the connected node
// will allow callers to traverse the graph in an object-oriented manner.
type ChannelEdge struct {
// Channel contains the attributes of this channel.
Channel
// Peer is the peer that this channel creates an edge to in the channel
// graph.
Peer Node
}
// ChannelGraph in an interface that represents a traversable channel graph.
// The autopilot agent will use this interface as its source of graph traits in
// order to make decisions concerning which channels should be opened, and to
// whom.
//
// TODO(roasbeef): abstract??
type ChannelGraph interface {
// ForEachNode is a higher-order function that should be called once
// for each connected node within the channel graph. If the passed
// callback returns an error, then execution should be terminated.
ForEachNode(func(Node) error) error
}
// AttachmentDirective describes a channel attachment proscribed by an
// AttachmentHeuristic. It details to which node a channel should be created
// to, and also the parameters which should be used in the channel creation.
type AttachmentDirective struct {
// NodeID is the serialized compressed pubkey of the target node for
// this attachment directive. It can be identified by its public key,
// and therefore can be used along with a ChannelOpener implementation
// to execute the directive.
NodeID NodeID
// ChanAmt is the size of the channel that should be opened, expressed
// in satoshis.
ChanAmt btcutil.Amount
// Addrs is a list of addresses that the target peer may be reachable
// at.
Addrs []net.Addr
// Score is the score given by the heuristic for opening a channel of
// the given size to this node.
Score float64
}
// AttachmentHeuristic is one of the primary interfaces within this package.
// Implementations of this interface will be used to implement a control system
// which automatically regulates channels of a particular agent, attempting to
// optimize channels opened/closed based on various heuristics. The purpose of
// the interface is to allow an auto-pilot agent to decide if it needs more
// channels, and if so, which exact channels should be opened.
type AttachmentHeuristic interface {
// NodeScores is a method that given the current channel graph and
// current set of local channels, scores the given nodes according to
// the preference of opening a channel of the given size with them. The
// returned channel candidates maps the NodeID to an attachment
// directive containing a score.
//
// The scores will be in the range [0, M], where 0 indicates no
// improvement in connectivity if a channel is opened to this node,
// while M is the maximum possible improvement in connectivity. The
// size of M is up to the implementation of this interface, so scores
// must be normalized if compared against other implementations.
//
// NOTE: A NodeID not found in the returned map is implicitly given a
// score of 0.
NodeScores(g ChannelGraph, chans []Channel,
chanSize btcutil.Amount, nodes map[NodeID]struct{}) (
map[NodeID]*AttachmentDirective, error)
}
// ChannelController is a simple interface that allows an auto-pilot agent to
// open a channel within the graph to a target peer, close targeted channels,
// or add/remove funds from existing channels via a splice in/out mechanisms.
type ChannelController interface {
// OpenChannel opens a channel to a target peer, with a capacity of the
// specified amount. This function should un-block immediately after
// the funding transaction that marks the channel open has been
// broadcast.
OpenChannel(target *btcec.PublicKey, amt btcutil.Amount) error
// CloseChannel attempts to close out the target channel.
//
// TODO(roasbeef): add force option?
CloseChannel(chanPoint *wire.OutPoint) error
// SpliceIn attempts to add additional funds to the target channel via
// a splice in mechanism. The new channel with an updated capacity
// should be returned.
SpliceIn(chanPoint *wire.OutPoint, amt btcutil.Amount) (*Channel, error)
// SpliceOut attempts to remove funds from an existing channels using a
// splice out mechanism. The removed funds from the channel should be
// returned to an output under the control of the backing wallet.
SpliceOut(chanPoint *wire.OutPoint, amt btcutil.Amount) (*Channel, error)
}