b56b080a7c
* introduce new interface "dnsserver.Viewer", that allows a plugin implementing it to decide if a query should be routed into its server block. * add new plugin "view", that uses the new interface to enable a user to define expression based conditions that must be met for a query to be routed to its server block. Signed-off-by: Chris O'Haver <cohaver@infoblox.com>
57 lines
1.7 KiB
Go
57 lines
1.7 KiB
Go
package metrics
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import (
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"context"
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"path/filepath"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/metrics/vars"
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"github.com/coredns/coredns/plugin/pkg/rcode"
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"github.com/coredns/coredns/request"
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"github.com/miekg/dns"
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)
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// ServeDNS implements the Handler interface.
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func (m *Metrics) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (int, error) {
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state := request.Request{W: w, Req: r}
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qname := state.QName()
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zone := plugin.Zones(m.ZoneNames()).Matches(qname)
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if zone == "" {
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zone = "."
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}
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// Record response to get status code and size of the reply.
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rw := NewRecorder(w)
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status, err := plugin.NextOrFailure(m.Name(), m.Next, ctx, rw, r)
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rc := rw.Rcode
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if !plugin.ClientWrite(status) {
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// when no response was written, fallback to status returned from next plugin as this status
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// is actually used as rcode of DNS response
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// see https://github.com/coredns/coredns/blob/master/core/dnsserver/server.go#L318
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rc = status
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}
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plugin := m.authoritativePlugin(rw.Caller)
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vars.Report(WithServer(ctx), state, zone, WithView(ctx), rcode.ToString(rc), plugin, rw.Len, rw.Start)
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return status, err
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}
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// Name implements the Handler interface.
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func (m *Metrics) Name() string { return "prometheus" }
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// authoritativePlugin returns which of made the write, if none is found the empty string is returned.
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func (m *Metrics) authoritativePlugin(caller [3]string) string {
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// a b and c contain the full path of the caller, the plugin name 2nd last elements
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// .../coredns/plugin/whoami/whoami.go --> whoami
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// this is likely FS specific, so use filepath.
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for _, c := range caller {
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plug := filepath.Base(filepath.Dir(c))
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if _, ok := m.plugins[plug]; ok {
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return plug
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}
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}
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return ""
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}
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