Improve debug logging in golang

main.go

@@ -3,8 +3,6 @@ package main
 import (
 	"flag"
 	"github.com/ry/v8worker2"
-	"io/ioutil"
-	"log"
 	"os"
 	"runtime/pprof"
 )
@@ -28,10 +26,6 @@ func FlagsParse() []string {
 	}
 	args = v8worker2.SetFlags(args)
 
-	// Unless the debug flag is specified, discard logs.
-	if !*flagDebug {
-		log.SetOutput(ioutil.Discard)
-	}
 	return args
 }
 
@@ -43,7 +37,7 @@ func main() {
 	if *flagGoProf != "" {
 		f, err := os.Create(*flagGoProf)
 		if err != nil {
-			log.Fatal(err)
+			panic(err)
 		}
 		pprof.StartCPUProfile(f)
 		defer pprof.StopCPUProfile()

os.go

@@ -3,7 +3,6 @@ package main
 import (
 	"github.com/golang/protobuf/proto"
 	"io/ioutil"
-	"log"
 	"net/url"
 	"os"
 	"path"
@@ -37,7 +36,7 @@ func InitOS() {
 func ResolveModule(moduleSpecifier string, containingFile string) (
 	moduleName string, filename string, err error) {
 
-	log.Printf("ResolveModule %s %s", moduleSpecifier, containingFile)
+	logDebug("ResolveModule %s %s", moduleSpecifier, containingFile)
 
 	moduleUrl, err := url.Parse(moduleSpecifier)
 	if err != nil {

util.go

@@ -1,10 +1,18 @@
 package main
 
 import (
+	"fmt"
 	"net/url"
 	"os"
 )
 
+func logDebug(format string, v ...interface{}) {
+	// Unless the debug flag is specified, discard logs.
+	if *flagDebug {
+		fmt.Printf(format+"\n", v)
+	}
+}
+
 func assert(cond bool, msg string) {
 	if !cond {
 		panic(msg)