added sync exporter draft

sync.go

@@ -0,0 +1,95 @@
+package main
+
+import (
+	"log"
+	"math/rand"
+	"net/http"
+
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+type CityStats struct {
+	Zone string
+}
+
+//temperature by country
+func (c *CityStats) TemperatureAndHumidity() (
+	tempByCity map[string]int, humidityByCity map[string]float64,
+) {
+	tempByCity = map[string]int{
+		"bangalore": rand.Intn(100),
+		"london":    rand.Intn(1000),
+	}
+	humidityByCity = map[string]float64{
+		"bangalore": rand.Float64(),
+		"london":    rand.Float64(),
+	}
+	return
+}
+
+type CityStatsCollector struct {
+	CityStats *CityStats
+}
+
+var (
+	tempDesc = prometheus.NewDesc(
+		"temperature_city_fahrenheit",
+		"temperature of a city in fahrenheit",
+		[]string{"city"}, nil,
+	)
+	humidityDesc = prometheus.NewDesc(
+		"humidity_city_fraction",
+		"humidity of a city as a fraction",
+		[]string{"city"}, nil,
+	)
+)
+
+func (cc CityStatsCollector) Describe(ch chan<- *prometheus.Desc) {
+	prometheus.DescribeByCollect(cc, ch)
+}
+
+func (cc CityStatsCollector) Collect(ch chan<- prometheus.Metric) {
+	tempByCity, humidityByCity := cc.CityStats.TemperatureAndHumidity()
+	for city, temp := range tempByCity {
+		ch <- prometheus.MustNewConstMetric(
+			tempDesc,
+			prometheus.CounterValue,
+			float64(temp),
+			city,
+		)
+	}
+	for city, humidity := range humidityByCity {
+		ch <- prometheus.MustNewConstMetric(
+			humidityDesc,
+			prometheus.GaugeValue,
+			humidity,
+			city,
+		)
+	}
+}
+
+func NewCityStats(zone string, reg prometheus.Registerer) *CityStats {
+	c := &CityStats{
+		Zone: zone,
+	}
+	cc := CityStatsCollector{CityStats: c}
+	prometheus.WrapRegistererWith(prometheus.Labels{"zone": zone}, reg).MustRegister(cc)
+	return c
+}
+
+func main() {
+	reg := prometheus.NewRegistry()
+
+	NewCityStats("db", reg)
+	NewCityStats("ca", reg)
+
+	// Add the standard process and Go metrics to the custom registry.
+	reg.MustRegister(
+		prometheus.NewProcessCollector(prometheus.ProcessCollectorOpts{}),
+		prometheus.NewGoCollector(),
+	)
+
+	http.Handle("/metrics", promhttp.HandlerFor(reg, promhttp.HandlerOpts{}))
+	log.Fatal(http.ListenAndServe(":2112", nil))
+}