Add getters for metrics and configuration options

examples/prometheus/prometheus.go

@@ -0,0 +1,56 @@
+package main
+
+import (
+	"fmt"
+	"net/http"
+	"time"
+
+	"github.com/alitto/pond"
+	"github.com/prometheus/client_golang/prometheus"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+func main() {
+
+	// Create a worker pool
+	pool := pond.New(10, 0)
+
+	// Register pool metrics collectors
+	prometheus.MustRegister(prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Name: "pond_running_workers",
+			Help: "Number of running worker goroutines",
+		},
+		func() float64 {
+			return float64(pool.RunningWorkers())
+		}))
+	prometheus.MustRegister(prometheus.NewGaugeFunc(
+		prometheus.GaugeOpts{
+			Name: "pond_idle_workers",
+			Help: "Number of idle worker goroutines",
+		},
+		func() float64 {
+			return float64(pool.IdleWorkers())
+		}))
+
+	// Expose the registered metrics via HTTP
+	http.Handle("/metrics", promhttp.Handler())
+
+	go submitTasks(pool)
+
+	// Start the server
+	http.ListenAndServe(":8080", nil)
+
+}
+
+func submitTasks(pool *pond.WorkerPool) {
+
+	// Submit 1000 tasks
+	for i := 0; i < 1000; i++ {
+		n := i
+		pool.Submit(func() {
+			fmt.Printf("Running task #%d\n", n)
+			time.Sleep(3 * time.Second)
+		})
+	}
+}