77 lines
2.7 KiB
Go
77 lines
2.7 KiB
Go
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package autopilot
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import (
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"github.com/btcsuite/btcutil"
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)
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// HeuristicConstraints is a struct that indicate the constraints an autopilot
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// heuristic must adhere to when opening channels.
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type HeuristicConstraints struct {
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// MinChanSize is the smallest channel that the autopilot agent should
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// create.
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MinChanSize btcutil.Amount
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// MaxChanSize the largest channel that the autopilot agent should
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// create.
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MaxChanSize btcutil.Amount
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// ChanLimit the maximum number of channels that should be created.
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ChanLimit uint16
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// Allocation the percentage of total funds that should be committed to
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// automatic channel establishment.
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Allocation float64
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// MaxPendingOpens is the maximum number of pending channel
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// establishment goroutines that can be lingering. We cap this value in
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// order to control the level of parallelism caused by the autopilot
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// agent.
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MaxPendingOpens uint16
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}
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// availableChans returns the funds and number of channels slots the autopilot
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// has available towards new channels, and still be within the set constraints.
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func (h *HeuristicConstraints) availableChans(channels []Channel,
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funds btcutil.Amount) (btcutil.Amount, uint32) {
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// If we're already over our maximum allowed number of channels, then
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// we'll instruct the controller not to create any more channels.
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if len(channels) >= int(h.ChanLimit) {
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return 0, 0
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}
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// The number of additional channels that should be opened is the
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// difference between the channel limit, and the number of channels we
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// already have open.
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numAdditionalChans := uint32(h.ChanLimit) - uint32(len(channels))
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// First, we'll tally up the total amount of funds that are currently
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// present within the set of active channels.
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var totalChanAllocation btcutil.Amount
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for _, channel := range channels {
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totalChanAllocation += channel.Capacity
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}
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// With this value known, we'll now compute the total amount of fund
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// allocated across regular utxo's and channel utxo's.
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totalFunds := funds + totalChanAllocation
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// Once the total amount has been computed, we then calculate the
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// fraction of funds currently allocated to channels.
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fundsFraction := float64(totalChanAllocation) / float64(totalFunds)
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// If this fraction is below our threshold, then we'll return true, to
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// indicate the controller should call Select to obtain a candidate set
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// of channels to attempt to open.
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needMore := fundsFraction < h.Allocation
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if !needMore {
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return 0, 0
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}
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// Now that we know we need more funds, we'll compute the amount of
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// additional funds we should allocate towards channels.
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targetAllocation := btcutil.Amount(float64(totalFunds) * h.Allocation)
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fundsAvailable := targetAllocation - totalChanAllocation
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return fundsAvailable, numAdditionalChans
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}
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