The document describes a Prometheus collector interface that allows exporting metrics from Go services to Prometheus. It defines a Collector interface with Describe and Collect methods to provide metric descriptions and values. It then shows examples of implementing the Collector interface to export metrics like request counts, failure rates, and other service metrics. The examples demonstrate initializing the metrics, gathering values, and exposing them via the Collector interface to Prometheus.

20. ✔

30. ✔

37. ✔

50. package prometheus
// Collector is the interface implemented by anything that can be used by
// Prometheus to collect metrics. A Collector has to be registered for
// collection. See Registerer.Register.
type Collector interface {
// Describe sends the super-set of all possible descriptors of metrics
// collected by this Collector to the provided channel and returns once
// the last descriptor has been sent.
Describe(chan<- *Desc)
// Collect is called by the Prometheus registry when collecting
// metrics. The implementation sends each collected metric via the
// provided
Collect(chan<- Metric)
}

70. ✔

73. Service A
Service B
Service C
Queue
Datastore
Service B
Service B
Service C
Service C

75. dorpc.SetLogger(loglvl.Level(
log.KV("component", "grpc"),
loglvl.Error,
))

76. mm, metricsHandler :=
metrics.Prometheus(metrics.PrometheusNamespace(app))
mm = mm.Labels(metrics.L{
"app": app,
"env": env.Env,
})
metrics.SetRoot(mm)

77. func (s *server) initalizeMetrics() {
s.metrics = metricsConfig{
attemptedConvergeChassis:
s.metricsNode.Gauge("attempted_converge_chassis", "number of
chassis converger attempting to converge"),
failedConvergeChassis:
s.metricsNode.Gauge("failed_converge_chassis", "number of
chassis that failed to converge"),
}
}

78. dbDriverName, traceOpt := tracemysql.MySQL()
// note: default buffer size is 64 * 1 << 10
tracerOpt := tracer.WithBufferSize(64 * 1 << 14)
bufferOpt := trace.UseTracerOptions(tracerOpt)
tr := trace.InitTracer(traceOpt, bufferOpt)
defer tr.Close()

86. Service A
Service B
Service C
QueueDatastore
Service B
Service B
Service C
Service C

91. Service B
DHCP server
Virtual
Switch
Service A RPC calls
Iface Y
DHCPv4
gRPC
DHCPv6
Iface X dropletX
DHCP traffic
RPC calls
Hypervisor

93. package dhcp4conn
var _ prometheus.Collector = &collector{}
type collector struct {
ReadBytesTotal *prometheus.Desc
ReadPacketsTotal *prometheus.Desc
WriteBytesTotal *prometheus.Desc
WritePacketsTotal *prometheus.Desc
}

100. workC := make(chan request, Workers)
for i := 0; i < Workers; i++ {
go func() {
defer workWG.Done()
for r := range workC {
s.serve(r.buf, r.from)
}
}()
}

101. type RateMap struct {
mu sync.Mutex
...
rateMap map[string]*rate
}
type RateMapCollector struct {
RequestRate *prometheus.Desc
rm *RateMap
buckets []float64
}
func (r *RateMapCollector) Collect(ch
chan<- prometheus.Metric) {
...
ch <-
prometheus.MustNewConstHistogram(
r.RequestRate,
count, sum,
rateCount)
}

102. Rate Limiter
Centralized
LoggingCentralized
LoggingCentralized
LoggingCentralized
Logging
Elastalert
emits log line

105. ●
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●