using promauto package to ensure all created metrics are properly registered

[zouyee]

1. Why is this pull request needed and what does it do?

check if metric is registererd

2. Which issues (if any) are related?

fix #4024

3. Which documentation changes (if any) need to be made?

none

4. Does this introduce a backward incompatible change or deprecation?

none

[codecov-commenter]

Codecov Report

Merging #4025 into master will decrease coverage by 0.05%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #4025      +/-   ##
==========================================
- Coverage   56.82%   56.77%   -0.06%     
==========================================
  Files         224      224              
  Lines       11352    11341      -11     
==========================================
- Hits         6451     6439      -12     
- Misses       4404     4406       +2     
+ Partials      497      496       -1     

Impacted Files	Coverage Δ
plugin/health/overloaded.go	57.89% <ø> (ø)
plugin/kubernetes/metrics.go	100.00% <ø> (+21.42%)	⬆️
plugin/template/metrics.go	33.33% <ø> (ø)
plugin/metrics/metrics.go	64.06% <100.00%> (-7.94%)	⬇️
plugin/file/reload.go	69.44% <0.00%> (-5.56%)	⬇️

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[zouyee]

/assign @miekg

[miekg]

thanks!

[SuperQ]

Nice. There are a number of additional MustRegister() instances that can probably be removed.

[miekg]

oh yeah, was wondering that during review, but:

lugin/dnssec/setup.go:		metrics.MustRegister(c, cacheSize, cacheHits, cacheMisses)
plugin/forward/setup.go:		metrics.MustRegister(c, RequestCount, RcodeCount, RequestDuration, HealthcheckFailureCount, SocketGauge, MaxConcurrentRejectCount)
plugin/reload/setup.go:			metrics.MustRegister(c, reloadInfo, failedCount)
plugin/acl/setup.go:		metrics.MustRegister(c, RequestBlockCount, RequestAllowCount)
plugin/hosts/setup.go:		metrics.MustRegister(c, hostsEntries)
plugin/hosts/setup.go:		metrics.MustRegister(c, hostsReloadTime)
plugin/grpc/setup.go:		metrics.MustRegister(c, RequestCount, RcodeCount, RequestDuration)
plugin/metrics/register.go:// MustRegister registers the prometheus Collectors when the metrics plugin is used.
plugin/metrics/register.go:func MustRegister(c *caddy.Controller, cs ...prometheus.Collector) {
plugin/metrics/register.go:		x.MustRegister(c)
plugin/metrics/metrics.go:// MustRegister wraps m.Reg.MustRegister.
plugin/metrics/metrics.go:func (m *Metrics) MustRegister(c prometheus.Collector) {
plugin/health/setup.go:		metrics.MustRegister(c, HealthDuration)
plugin/template/metrics.go:		metrics.MustRegister(c, templateMatchesCount, templateFailureCount, templateRRFailureCount)
plugin/kubernetes/setup.go:		metrics.MustRegister(c, DnsProgrammingLatency)
plugin/autopath/setup.go:		metrics.MustRegister(c, autoPathCount)
plugin/cache/setup.go:		metrics.MustRegister(c,
plugin/dns64/setup.go:		metrics.MustRegister(c, RequestsTranslatedCount)

[miekg]

maybe we can add a smaller test in presubmit_test that check for MustRegister (instead of the Makefile test added here?)?

[zouyee]

maybe we can add a smaller test in presubmit_test that check for MustRegister (instead of the Makefile test added here?)?

The promauto functions contains the registration function, the MustRegister method could be removed or discarded?

[SuperQ]

LGTM

[yongtang]

LGTM, Thanks!