* plugin/metrics: set server address in context
Allow cross server block metrics to co-exist; for this we should label
each metric with the server label. Put this information in the context
and provide a helper function to get it out.
Abstracting with entirely away with difficult as the release client_go
(0.8.0) doesn't have the CurryWith functions yet. So current use is like
so:
define metric, with server label:
RcodeCount = prometheus.NewCounterVec(prometheus.CounterOpts{
Namespace: plugin.Namespace,
Subsystem: "forward",
Name: "response_rcode_count_total",
Help: "Counter of requests made per upstream.",
}, []string{"server", "rcode", "to"})
And report ith with the helper function metrics.WithServer:
RcodeCount.WithLabelValues(metrics.WithServer(ctx), rc, p.addr).Add(1)
This leave most of the code intact, but we need to stop vendoring
prometheus, because, again, plugins what want to use it. Not vendoring
prometheus makes my forward metrics show up again. Code looks bit
convoluted, but works:
~~~
c.OnStartup(func() error {
once.Do(func() {
m := dnsserver.GetConfig(c).Handler("prometheus")
if m == nil {
return
}
if x, ok := m.(*metrics.Metrics); ok {
x.MustRegister(RequestCount)
x.MustRegister(RcodeCount)
x.MustRegister(RequestDuration)
x.MustRegister(HealthcheckFailureCount)
x.MustRegister(SocketGauge)
}
})
})
~~~
prometheus.Handler is deprecated according to the godoc for the package so
instead we're using promhttp.
Additionally, we are exposing the Registry that metrics is using so other
plugins that are not inside of coredns can read the registry. Otherwise, if
we kept using the Default one, there's no way to access that from outside
of the coredns repo since it is vendored.
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.
* Rename middleware to plugin
first pass; mostly used 'sed', few spots where I manually changed
text.
This still builds a coredns binary.
* fmt error
* Rename AddMiddleware to AddPlugin
* Readd AddMiddleware to remain backwards compat
2017-09-14 09:36:06 +01:00
Renamed from middleware/metrics/metrics.go (Browse further)
