Metrics (#1579)
* 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)
											
										 
										
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								package metrics
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								import (
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									"context"
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									"github.com/coredns/coredns/plugin/metrics/vars"
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												Metrics (#1579)
* 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)
											
										 
										
											2018-04-01 13:57:03 +01:00
										 
									 
								 
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								)
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								// WithServer returns the current server handling the request. It returns the
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								// server listening address: <scheme>://[<bind>]:<port> Normally this is
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								// something like "dns://:53", but if the bind plugin is used, i.e. "bind
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								// 127.0.0.53", it will be "dns://127.0.0.53:53", etc. If not address is found
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								// the empty string is returned.
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								//
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								// Basic usage with a metric:
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								//
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								// <metric>.WithLabelValues(metrics.WithServer(ctx), labels..).Add(1)
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											2018-04-18 09:42:20 +01:00
										 
									 
								 
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								func WithServer(ctx context.Context) string { return vars.WithServer(ctx) }
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