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https://github.com/coredns/coredns.git
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16504234e5
* plugin/forward: on demand healtchecking Only start doing health checks when we encouner an error (any error). This uses the new pluing/pkg/up package to abstract away the actual checking. This reduces the LOC quite a bit; does need more testing, unit testing and tcpdumping a bit. * fix tests * Fix readme * Use pkg/up for healthchecks * remove unused channel * more cleanups * update readme * * Again do go generate and go build; still referencing the wrong forward repo? Anyway fixed. * Use pkg/up for doing the healtchecks to cut back on unwanted queries * Change up.Func to return an error instead of a boolean. * Drop the string target argument as it doesn't make sense. * Add healthcheck test on failing to get an upstream answer. TODO(miek): double check Forward and Lookup and how they interact with HC, and if we correctly call close() on those * actual test * Tests here * more tests * try getting rid of host * Get rid of the host indirection * Finish removing hosts * moar testing * import fmt * field is not used * docs * move some stuff * bring back health_check * maxfails=0 test * git and merging, bah * review
41 lines
928 B
Go
41 lines
928 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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hcping.RecursionDesired = false
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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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