cleanup: move pkg/ to internal/

The internal/ directory in Go has a special meaning, and indicates that
those packages are not meant for external consumption. Ceph-CSI does
provide public APIs for other projects to consume. There is no plan to
keep the API of the internally used packages stable.

Closes: #903
Signed-off-by: Niels de Vos <ndevos@redhat.com>

internal/util/httpserver.go

@@ -0,0 +1,27 @@
+package util
+
+import (
+	"net"
+	"net/http"
+	"net/url"
+	"strconv"
+
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+	"k8s.io/klog"
+)
+
+// ValidateURL validates the url
+func ValidateURL(c *Config) error {
+	_, err := url.Parse(c.MetricsPath)
+	return err
+}
+
+// StartMetricsServer starts http server
+func StartMetricsServer(c *Config) {
+	addr := net.JoinHostPort(c.MetricsIP, strconv.Itoa(c.MetricsPort))
+	http.Handle(c.MetricsPath, promhttp.Handler())
+	err := http.ListenAndServe(addr, nil)
+	if err != nil {
+		klog.Fatalln(err)
+	}
+}