62 lines
1.8 KiB
Go
62 lines
1.8 KiB
Go
package lib
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import (
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"math"
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"time"
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"github.com/hashicorp/serf/coordinate"
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)
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// ComputeDistance returns the distance between the two network coordinates in
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// seconds. If either of the coordinates is nil then this will return positive
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// infinity.
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func ComputeDistance(a *coordinate.Coordinate, b *coordinate.Coordinate) float64 {
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if a == nil || b == nil {
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return math.Inf(1.0)
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}
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return a.DistanceTo(b).Seconds()
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}
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// CoordinateSet holds all the coordinates for a given node, indexed by network
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// segment name.
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type CoordinateSet map[string]*coordinate.Coordinate
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// Intersect tries to return a pair of coordinates which are compatible with the
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// current set and a given set. We employ some special knowledge about network
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// segments to avoid doing a full intersection, since this is in several hot
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// paths. This might return nil for either coordinate in the output pair if an
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// intersection cannot be found. The ComputeDistance function above is designed
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// to deal with that.
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func (cs CoordinateSet) Intersect(other CoordinateSet) (*coordinate.Coordinate, *coordinate.Coordinate) {
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// Use the empty segment by default.
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segment := ""
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// If we have a single segment, then let our segment take priority since
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// we are possibly a client. Any node with more than one segment can only
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// be a server, which means it should be in all segments.
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if len(cs) == 1 {
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for s := range cs {
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segment = s
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}
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}
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// Likewise for the other set.
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if len(other) == 1 {
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for s := range other {
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segment = s
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}
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}
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return cs[segment], other[segment]
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}
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// GenerateCoordinate creates a new coordinate with the given distance from the
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// origin. This should only be used for tests.
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func GenerateCoordinate(rtt time.Duration) *coordinate.Coordinate {
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coord := coordinate.NewCoordinate(coordinate.DefaultConfig())
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coord.Vec[0] = rtt.Seconds()
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coord.Height = 0
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return coord
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}
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