90 lines
2.9 KiB
Go
90 lines
2.9 KiB
Go
// Copyright (c) 2015 Uber Technologies, Inc.
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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package tchannel
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import "math"
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// ScoreCalculator defines the interface to calculate the score.
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type ScoreCalculator interface {
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GetScore(p *Peer) uint64
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}
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// ScoreCalculatorFunc is an adapter that allows functions to be used as ScoreCalculator
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type ScoreCalculatorFunc func(p *Peer) uint64
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// GetScore calls the underlying function.
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func (f ScoreCalculatorFunc) GetScore(p *Peer) uint64 {
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return f(p)
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}
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type zeroCalculator struct{}
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func (zeroCalculator) GetScore(p *Peer) uint64 {
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return 0
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}
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func newZeroCalculator() zeroCalculator {
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return zeroCalculator{}
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}
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type leastPendingCalculator struct{}
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func (leastPendingCalculator) GetScore(p *Peer) uint64 {
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inbound, outbound := p.NumConnections()
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if inbound+outbound == 0 {
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return math.MaxUint64
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}
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return uint64(p.NumPendingOutbound())
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}
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// newLeastPendingCalculator returns a strategy prefers any connected peer.
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// Within connected peers, least pending calls is used. Peers with less pending outbound calls
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// get a smaller score.
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func newLeastPendingCalculator() leastPendingCalculator {
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return leastPendingCalculator{}
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}
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type preferIncomingCalculator struct{}
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func (preferIncomingCalculator) GetScore(p *Peer) uint64 {
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inbound, outbound := p.NumConnections()
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if inbound+outbound == 0 {
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return math.MaxUint64
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}
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numPendingOutbound := uint64(p.NumPendingOutbound())
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if inbound == 0 {
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return math.MaxInt32 + numPendingOutbound
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}
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return numPendingOutbound
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}
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// newPreferIncomingCalculator returns a strategy that prefers peers with incoming connections.
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// The scoring tiers are:
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// Peers with incoming connections, peers with any connections, unconnected peers.
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// Within each tier, least pending calls is used. Peers with less pending outbound calls
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// get a smaller score.
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func newPreferIncomingCalculator() preferIncomingCalculator {
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return preferIncomingCalculator{}
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}
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