2ef55f805e
Fix metrics endpoint on a failed reload, follows the same lines as the
previous PRs, see for e.g. 076b8d4f. Test with a Corefile with 2 server
blocks and metrics enabled and then introducing a syntax error:
~~~
[ERROR] Restart failed: Corefile:5 - Error during parsing: Unknown directive 'jfkdjk'
[ERROR] SIGUSR1: starting with listener file descriptors: Corefile:5 - Error during parsing: Unknown directive 'jfkdjk'
~~~
And then curl-ing the metrics endpoint.
See #2659 and as this is the last one.
Fixes: #2659
Getting this all right turns out to be tricky, also it's not easy
testable which is something I should fix.
Signed-off-by: Miek Gieben <miek@miek.nl>
108 lines
2.5 KiB
Go
108 lines
2.5 KiB
Go
package metrics
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import (
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"net"
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"runtime"
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"github.com/coredns/coredns/core/dnsserver"
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"github.com/coredns/coredns/coremain"
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"github.com/coredns/coredns/plugin"
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"github.com/coredns/coredns/plugin/metrics/vars"
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clog "github.com/coredns/coredns/plugin/pkg/log"
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"github.com/coredns/coredns/plugin/pkg/uniq"
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"github.com/mholt/caddy"
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)
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var (
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log = clog.NewWithPlugin("prometheus")
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uniqAddr = uniq.New()
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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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}
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func setup(c *caddy.Controller) error {
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m, err := parse(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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c.OnStartup(func() error { m.Reg = uniqAddr.Set(m.Addr, m.OnStartup, m).(*Metrics).Reg; return nil })
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c.OnRestartFailed(func() error { m.Reg = uniqAddr.Set(m.Addr, m.OnStartup, m).(*Metrics).Reg; return nil })
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c.OnStartup(func() error { return uniqAddr.ForEach() })
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c.OnRestartFailed(func() error { return uniqAddr.ForEach() })
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c.OnStartup(func() error {
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conf := dnsserver.GetConfig(c)
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for _, h := range conf.ListenHosts {
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addrstr := conf.Transport + "://" + net.JoinHostPort(h, conf.Port)
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for _, p := range conf.Handlers() {
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vars.PluginEnabled.WithLabelValues(addrstr, conf.Zone, p.Name()).Set(1)
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}
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}
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return nil
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})
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c.OnRestartFailed(func() error {
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conf := dnsserver.GetConfig(c)
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for _, h := range conf.ListenHosts {
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addrstr := conf.Transport + "://" + net.JoinHostPort(h, conf.Port)
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for _, p := range conf.Handlers() {
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vars.PluginEnabled.WithLabelValues(addrstr, conf.Zone, p.Name()).Set(1)
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}
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}
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return nil
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})
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c.OnRestart(m.OnRestart)
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c.OnRestart(func() error { vars.PluginEnabled.Reset(); return nil })
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c.OnFinalShutdown(m.OnFinalShutdown)
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// Initialize metrics.
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buildInfo.WithLabelValues(coremain.CoreVersion, coremain.GitCommit, runtime.Version()).Set(1)
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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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return nil
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}
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func parse(c *caddy.Controller) (*Metrics, error) {
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var met = New(defaultAddr)
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i := 0
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for c.Next() {
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if i > 0 {
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return nil, plugin.ErrOnce
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}
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i++
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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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// defaultAddr is the address the where the metrics are exported by default.
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const defaultAddr = "localhost:9153"
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