add quiet flag to disable logging

main.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"io/ioutil"
 	"os"
 	"os/signal"
 	"strings"
@@ -63,6 +64,11 @@ func main() {
 			}
 		}
 
+		if appOptions.Quiet {
+			log.SetFlags(0)
+			log.SetOutput(ioutil.Discard)
+		}
+
 		utils.ApplyFlags(cliFlags, flagMappings, c, appOptions, backendOptions)
 
 		if c.IsSet("credential") {

server/options.go

@@ -32,6 +32,7 @@ type Options struct {
 	WSOrigin            string           `hcl:"ws_origin" flagName:"ws-origin" flagDescribe:"A regular expression that matches origin URLs to be accepted by WebSocket. No cross origin requests are acceptable by default" default:""`
 	Term                string           `hcl:"term" flagName:"term" flagDescribe:"Terminal name to use on the browser, one of xterm or hterm." default:"xterm"`
 	EnableWebGL         bool             `hcl:"enable_webgl" flagName:"enable-webgl" flagDescribe:"Enable WebGL renderer" default:"true"`
+	Quiet               bool             `hcl:"quiet" flagName:"quiet" flagDescribe:"Don't log" default:"false"`
 
 	TitleVariables map[string]interface{}
 }