76 lines
1.6 KiB
Go
76 lines
1.6 KiB
Go
// Package allocator.util is a utility package used by the allocator
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// implementations. This package provides the SortNumeric function, which may be
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// used by an allocator to sort peers by their metric values (ascending or
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// descending).
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package util
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import (
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"sort"
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"strconv"
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"github.com/ipfs/ipfs-cluster/api"
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peer "github.com/libp2p/go-libp2p-peer"
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)
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// SortNumeric returns a list of peers sorted by their metric values. If reverse
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// is false (true), peers will be sorted from smallest to largest (largest to
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// smallest) metric
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func SortNumeric(candidates map[peer.ID]api.Metric, reverse bool) []peer.ID {
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vMap := make(map[peer.ID]int)
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peers := make([]peer.ID, 0, len(candidates))
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for k, v := range candidates {
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if v.Discard() {
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continue
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}
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val, err := strconv.Atoi(v.Value)
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if err != nil {
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continue
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}
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peers = append(peers, k)
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vMap[k] = val
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}
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sorter := &metricSorter{
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m: vMap,
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peers: peers,
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reverse: reverse,
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}
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sort.Sort(sorter)
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return sorter.peers
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}
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// metricSorter implements the sort.Sort interface
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type metricSorter struct {
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peers []peer.ID
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m map[peer.ID]int
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reverse bool
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}
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// Len returns the number of metrics
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func (s metricSorter) Len() int {
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return len(s.peers)
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}
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// Swap Swaps the elements in positions i and j
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func (s metricSorter) Swap(i, j int) {
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temp := s.peers[i]
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s.peers[i] = s.peers[j]
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s.peers[j] = temp
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}
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// Less reports if the element in position i is Less than the element in j
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// (important to override this)
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func (s metricSorter) Less(i, j int) bool {
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peeri := s.peers[i]
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peerj := s.peers[j]
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x := s.m[peeri]
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y := s.m[peerj]
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if s.reverse {
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return x > y
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}
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return x < y
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}
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