func (p PcpSource) Describe(ch chan<- *prometheus.Desc) {
	scrapeDurations.Describe(ch)
}
Describe implements the prometheus.Describe interface
package main
import (
	"flag"
	"fmt"
	"net/http"
	"os"
	"sync"
	"time"
	"github.com/HewlettPackard/pcp_exporter/sources"
	"github.com/prometheus/client_golang/prometheus"
	"github.com/prometheus/client_golang/prometheus/promhttp"
	"github.com/prometheus/common/log"
	"github.com/prometheus/common/version"
)
var (
	scrapeDurations = prometheus.NewSummaryVec(
		prometheus.SummaryOpts{
			Namespace: sources.Namespace,
			Subsystem: "exporter",
			Name:      "scrape_duration_seconds",
			Help:      "pcp_exporter: Duration of a scrape job.",
		},
		[]string{"source", "result"},
	)
)
type PcpSource struct {
	sourceList map[string]sources.PcpSource
}