Refactor cpu collector to use perflib instead of WMI.

collector/collector.go

@@ -0,0 +1,39 @@
+package collector
+
+import (
+	"github.com/leoluk/perflib_exporter/perflib"
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+// ...
+const (
+	// TODO: Make package-local
+	Namespace = "wmi"
+
+	// Conversion factors
+	ticksToSecondsScaleFactor = 1 / 1e7
+	windowsEpoch              = 116444736000000000
+)
+
+// Factories ...
+var Factories = make(map[string]func() (Collector, error))
+
+// Collector is the interface a collector has to implement.
+type Collector interface {
+	// Get new metrics and expose them via prometheus registry.
+	Collect(ctx *ScrapeContext, ch chan<- prometheus.Metric) (err error)
+}
+
+type ScrapeContext struct {
+	perfObjects map[string]*perflib.PerfObject
+}
+
+// PrepareScrapeContext creates a ScrapeContext to be used during a single scrape
+func PrepareScrapeContext() (*ScrapeContext, error) {
+	objs, err := getPerflibSnapshot()
+	if err != nil {
+		return nil, err
+	}
+
+	return &ScrapeContext{objs}, nil
+}