1919913c98
If external plugins wanted to extend metrics there was no way since zoneNames couldn't be initialized. Now plugins can call New to get an instance of Metrics that they can extend.
97 lines
1.8 KiB
Go
97 lines
1.8 KiB
Go
package metrics
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import (
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"net"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/plugin"
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"github.com/mholt/caddy"
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)
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func init() {
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caddy.RegisterPlugin("prometheus", caddy.Plugin{
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ServerType: "dns",
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Action: setup,
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})
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uniqAddr = addrs{a: make(map[string]int)}
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}
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func setup(c *caddy.Controller) error {
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m, err := prometheusParse(c)
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if err != nil {
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return plugin.Error("prometheus", err)
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}
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dnsserver.GetConfig(c).AddPlugin(func(next plugin.Handler) plugin.Handler {
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m.Next = next
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return m
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})
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for a, v := range uniqAddr.a {
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if v == todo {
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// During restarts we will keep this handler running, BUG.
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c.OncePerServerBlock(m.OnStartup)
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}
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uniqAddr.a[a] = done
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}
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c.OnFinalShutdown(m.OnShutdown)
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return nil
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}
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func prometheusParse(c *caddy.Controller) (*Metrics, error) {
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var met = New(defaultAddr)
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defer func() {
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uniqAddr.SetAddress(met.Addr)
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}()
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for c.Next() {
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if len(met.ZoneNames()) > 0 {
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return met, c.Err("can only have one metrics module per server")
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}
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for _, z := range c.ServerBlockKeys {
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met.AddZone(plugin.Host(z).Normalize())
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}
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args := c.RemainingArgs()
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switch len(args) {
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case 0:
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case 1:
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met.Addr = args[0]
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_, _, e := net.SplitHostPort(met.Addr)
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if e != nil {
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return met, e
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}
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default:
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return met, c.ArgErr()
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}
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}
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return met, nil
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}
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var uniqAddr addrs
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// Keep track on which addrs we listen, so we only start one listener.
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type addrs struct {
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a map[string]int
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}
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func (a *addrs) SetAddress(addr string) {
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// If already there and set to done, we've already started this listener.
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if a.a[addr] == done {
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return
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}
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a.a[addr] = todo
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}
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// defaultAddr is the address the where the metrics are exported by default.
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const defaultAddr = "localhost:9153"
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const (
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todo = 1
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done = 2
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)
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