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https://github.com/coredns/coredns.git
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60227bd8d2
Pre-allocate slice capacity in AutoPath to eliminate unnecessary memory reallocations. This avoids slice growth when appending search domains and sentinel value. Benchmark shows significant performance improvement: - Before: 538.6 ns/op, 560 B/op, 13 allocs/op - After: 436.8 ns/op, 336 B/op, 11 allocs/op - Result: 19% faster, 40% less memory, 15% fewer allocations The optimization benefits Kubernetes clusters using autopath for server-side search path completion. Adds benchmark test to measure AutoPath performance. Signed-off-by: Ville Vesilehto <ville@vesilehto.fi>
60 lines
1.5 KiB
Go
60 lines
1.5 KiB
Go
package kubernetes
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import (
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/kubernetes/object"
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"github.com/coredns/coredns/request"
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)
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// AutoPath implements the AutoPathFunc call from the autopath plugin.
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// It returns a per-query search path or nil indicating no searchpathing should happen.
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func (k *Kubernetes) AutoPath(state request.Request) []string {
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// Check if the query falls in a zone we are actually authoritative for and thus if we want autopath.
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zone := plugin.Zones(k.Zones).Matches(state.Name())
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if zone == "" {
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return nil
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}
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// cluster.local {
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// autopath @kubernetes
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// kubernetes {
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// pods verified #
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// }
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// }
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// if pods != verified will cause panic and return SERVFAIL, expect worked as normal without autopath function
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if !k.opts.initPodCache {
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return nil
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}
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ip := state.IP()
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pod := k.podWithIP(ip)
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if pod == nil {
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return nil
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}
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totalSize := 3 + len(k.autoPathSearch) + 1 // +1 for sentinel
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search := make([]string, 0, totalSize)
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if zone == "." {
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search = append(search, pod.Namespace+".svc.", "svc.", ".")
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} else {
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search = append(search, pod.Namespace+".svc."+zone, "svc."+zone, zone)
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}
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search = append(search, k.autoPathSearch...)
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search = append(search, "") // sentinel
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return search
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}
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// podWithIP returns the api.Pod for source IP. It returns nil if nothing can be found.
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func (k *Kubernetes) podWithIP(ip string) *object.Pod {
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if k.podMode != podModeVerified {
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return nil
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}
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ps := k.APIConn.PodIndex(ip)
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if len(ps) == 0 {
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return nil
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}
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return ps[0]
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}
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