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plugin/metrcs: fix datarace on listeners (#2835)

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This fixes a data race on the listener(s) that get started in the
metrics plugins.

It also restore pkg/uniq to its former glory and removes and state being
carried in there; this means for metrics that registry.go was to
replicate that behavior *with* locking (as pkg/uniq doesn't do, or need
that).

Also renamed uniqAddr to just u, to make it slightly shorter.

Signed-off-by: Miek Gieben <miek@miek.nl>
This commit is contained in:
Miek Gieben 2019-05-18 18:34:46 +01:00 • committed by GitHub
parent d41e9ff7b7
commit 118b0c9408
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6 changed files with 62 additions and 30 deletions
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29
plugin/metrics/metrics.go
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@ -15,22 +15,24 @@ import (
"github.com/prometheus/client_golang/prometheus/promhttp"
)
// Metrics holds the prometheus configuration. The metrics' path is fixed to be /metrics
// Metrics holds the prometheus configuration. The metrics' path is fixed to be /metrics .
type Metrics struct {
Next plugin.Handler
Addr string
Reg *prometheus.Registry
Next plugin.Handler
Addr string
Reg *prometheus.Registry
ln net.Listener
lnSetup bool
mux *http.ServeMux
srv *http.Server
mux *http.ServeMux
srv *http.Server
zoneNames []string
zoneMap map[string]struct{}
zoneMu sync.RWMutex
}
// New returns a new instance of Metrics with the given address
// New returns a new instance of Metrics with the given address.
func New(addr string) *Metrics {
met := &Metrics{
Addr: addr,
@ -101,14 +103,19 @@ func (m *Metrics) OnStartup() error {
m.ln = ln
m.lnSetup = true
ListenAddr = m.ln.Addr().String() // For tests
m.mux = http.NewServeMux()
m.mux.Handle("/metrics", promhttp.HandlerFor(m.Reg, promhttp.HandlerOpts{}))
m.srv = &http.Server{Handler: m.mux}
// creating some helper variables to avoid data races on m.srv and m.ln
server := &http.Server{Handler: m.mux}
m.srv = server
go func() {
m.srv.Serve(m.ln)
server.Serve(ln)
}()
ListenAddr = ln.Addr().String() // For tests.
return nil
}
@ -117,7 +124,7 @@ func (m *Metrics) OnRestart() error {
if !m.lnSetup {
return nil
}
uniqAddr.Unset(m.Addr)
u.Unset(m.Addr)
return m.stopServer()
}