84 lines
2.2 KiB
Go
84 lines
2.2 KiB
Go
// Package apcupsdexporter provides the Exporter type used in the
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// apcupsd_exporter Prometheus exporter.
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package apcupsdexporter
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import (
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"context"
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"log"
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"time"
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"github.com/mdlayher/apcupsd"
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"github.com/prometheus/client_golang/prometheus"
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)
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const (
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// namespace is the top-level namespace for this apcupsd exporter.
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namespace = "apcupsd"
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)
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// An Exporter is a Prometheus exporter for apcupsd metrics.
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// It wraps all apcupsd metrics collectors and provides a single global
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// exporter which can serve metrics.
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//
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// It implements the prometheus.Collector interface in order to register
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// with Prometheus.
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type Exporter struct {
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clientFn ClientFunc
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}
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var _ prometheus.Collector = &Exporter{}
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// A ClientFunc is a function which can return an apcupsd NIS client.
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// ClientFuncs are invoked on each Prometheus scrape, so that connections
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// can be short-lived and less likely to time out or fail.
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type ClientFunc func(ctx context.Context) (*apcupsd.Client, error)
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// New creates a new Exporter which collects metrics by creating a apcupsd
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// client using the input ClientFunc.
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func New(fn ClientFunc) *Exporter {
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return &Exporter{
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clientFn: fn,
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}
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}
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// Describe sends all the descriptors of the collectors included to
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// the provided channel.
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func (e *Exporter) Describe(ch chan<- *prometheus.Desc) {
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e.withCollectors(func(cs []prometheus.Collector) {
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for _, c := range cs {
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c.Describe(ch)
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}
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})
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}
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// Collect sends the collected metrics from each of the collectors to
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// prometheus.
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func (e *Exporter) Collect(ch chan<- prometheus.Metric) {
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e.withCollectors(func(cs []prometheus.Collector) {
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for _, c := range cs {
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c.Collect(ch)
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}
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})
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}
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// withCollectors sets up an apcupsd client and creates a set of prometheus
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// collectors. It invokes the input closure and then cleans up after the
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// closure returns.
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func (e *Exporter) withCollectors(fn func(cs []prometheus.Collector)) {
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ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
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defer cancel()
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c, err := e.clientFn(ctx)
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if err != nil {
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log.Printf("error creating apcupsd client: %v", err)
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return
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}
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defer c.Close()
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cs := []prometheus.Collector{
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NewUPSCollector(c),
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}
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fn(cs)
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}
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