mirror of
https://github.com/coredns/coredns.git
synced 2025-11-03 18:53:13 -05:00
40 lines
895 B
Go
40 lines
895 B
Go
package forward
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import (
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"sync/atomic"
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"github.com/miekg/dns"
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)
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// For HC we send to . IN NS +norec message to the upstream. Dial timeouts and empty
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// replies are considered fails, basically anything else constitutes a healthy upstream.
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// Check is used as the up.Func in the up.Probe.
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func (p *Proxy) Check() error {
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err := p.send()
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if err != nil {
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HealthcheckFailureCount.WithLabelValues(p.addr).Add(1)
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atomic.AddUint32(&p.fails, 1)
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return err
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}
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atomic.StoreUint32(&p.fails, 0)
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return nil
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}
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func (p *Proxy) send() error {
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hcping := new(dns.Msg)
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hcping.SetQuestion(".", dns.TypeNS)
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m, _, err := p.client.Exchange(hcping, p.addr)
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// If we got a header, we're alright, basically only care about I/O errors 'n stuff
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if err != nil && m != nil {
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// Silly check, something sane came back
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if m.Response || m.Opcode == dns.OpcodeQuery {
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err = nil
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}
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}
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return err
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}
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