Aleksey Shakhmatov
8d322123a4
Implements balancer middleware with URL rewriting per-request: - RoundRobin, Failover, and WeightedRandom endpoint selection strategies - Background HealthChecker with configurable probe interval and path - Thread-safe health state tracking with sync.RWMutex
43 lines
862 B
Go
43 lines
862 B
Go
package balancer
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import "math/rand/v2"
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type weightedRandom struct{}
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// WeightedRandom returns a strategy that selects endpoints randomly,
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// weighted by each endpoint's Weight field. Endpoints with Weight <= 0
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// are treated as having a weight of 1.
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func WeightedRandom() Strategy {
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return &weightedRandom{}
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}
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func (w *weightedRandom) Next(healthy []Endpoint) (Endpoint, error) {
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if len(healthy) == 0 {
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return Endpoint{}, ErrNoHealthy
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}
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totalWeight := 0
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for _, ep := range healthy {
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weight := ep.Weight
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if weight <= 0 {
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weight = 1
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}
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totalWeight += weight
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}
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r := rand.IntN(totalWeight)
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for _, ep := range healthy {
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weight := ep.Weight
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if weight <= 0 {
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weight = 1
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}
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r -= weight
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if r < 0 {
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return ep, nil
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}
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}
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// Should never reach here, but return last endpoint as a safeguard.
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return healthy[len(healthy)-1], nil
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}
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