Merge pull request #162 from gvengel/tls-server-name-errors

Add error messaging when the --memcached.tls.server-name flag is required

cmd/memcached_exporter/main.go

@@ -18,6 +18,7 @@ import (
 	"net"
 	"net/http"
 	"os"
+	"strings"
 
 	"github.com/alecthomas/kingpin/v2"
 	"github.com/go-kit/log/level"
@@ -66,7 +67,13 @@ func main() {
 		if *serverName == "" {
 			*serverName, _, err = net.SplitHostPort(*address)
 			if err != nil {
-				level.Error(logger).Log("msg", "Error running HTTP server", "err", err)
+				if strings.Contains(*address, "/") {
+					level.Error(logger).Log("msg",
+						"If --memcached.tls.enable is set and --memcached.address is a unix socket, "+
+							"you must also specify --memcached.tls.server-name")
+				} else {
+					level.Error(logger).Log("msg", "Error parsing memcached address", "err", err)
+				}
 				os.Exit(1)
 			}
 		}