Merge pull request #42 from linkdata/logerror

Logerror

jaws.go

@@ -15,7 +15,6 @@ import (
 	"fmt"
 	"html/template"
 	"io"
-	"log"
 	"net"
 	"net/http"
 	"net/netip"
@@ -41,9 +40,9 @@ const (
 type Jid = jid.Jid // convenience alias
 
 type Jaws struct {
-	CookieName   string      // Name for session cookies, defaults to "jaws"
-	Logger       *log.Logger // If not nil, send debug info and errors here
-	Debug        bool        // set to true to enable debugging output
+	CookieName   string // Name for session cookies, defaults to "jaws"
+	Logger       any    // If not nil, send debug info and errors here
+	Debug        bool   // set to true to enable debugging output
 	doneCh       <-chan struct{}
 	bcastCh      chan Message
 	subCh        chan subscription
@@ -167,7 +166,7 @@ func (jw *Jaws) RequestCount() (n int) {
 // Returns err.
 func (jw *Jaws) Log(err error) error {
 	if err != nil && jw != nil && jw.Logger != nil {
-		jw.Logger.Println(err.Error())
+		LogError(jw.Logger, err.Error())
 	}
 	return err
 }
@@ -178,7 +177,7 @@ func (jw *Jaws) Log(err error) error {
 func (jw *Jaws) MustLog(err error) {
 	if err != nil {
 		if jw != nil && jw.Logger != nil {
-			jw.Logger.Println(err.Error())
+			LogError(jw.Logger, err.Error())
 		} else {
 			panic(err)
 		}

logerror.go

@@ -0,0 +1,29 @@
+package jaws
+
+import (
+	"fmt"
+	"io"
+	"strings"
+)
+
+type printlner interface {
+	Println(v ...any)
+}
+
+type errorer interface {
+	Error(msg string, args ...any)
+}
+
+// LogError is an adapter allowing logging an informational message
+// to a log.Logger, slog.Logger or io.Writer.
+func LogError(logger any, format string, args ...any) {
+	msg := fmt.Sprintf(strings.TrimRight(format, "\n"), args...)
+	switch x := logger.(type) {
+	case printlner:
+		x.Println(msg)
+	case errorer:
+		x.Error(msg)
+	case io.Writer:
+		_, _ = fmt.Fprintln(x, msg)
+	}
+}

logerror_test.go

@@ -0,0 +1,46 @@
+package jaws
+
+import (
+	"bytes"
+	"fmt"
+	"testing"
+)
+
+type printlnerImpl struct {
+	str string
+}
+
+func (x *printlnerImpl) Println(args ...any) {
+	x.str += fmt.Sprint(args...)
+}
+
+type errorerImpl struct {
+	str string
+}
+
+func (x *errorerImpl) Error(msg string, args ...any) {
+	x.str += msg
+}
+
+func TestLogError(t *testing.T) {
+	a := printlnerImpl{}
+	LogError(&a, "a")
+	LogError(&a, "\na\n")
+	if a.str != "a\na" {
+		t.Errorf("%q", a.str)
+	}
+
+	b := errorerImpl{}
+	LogError(&b, "b")
+	LogError(&b, "\nb\n")
+	if b.str != "b\nb" {
+		t.Errorf("%q", b.str)
+	}
+
+	var c bytes.Buffer
+	LogError(&c, "c")
+	LogError(&c, "\nc\n")
+	if c.String() != "c\n\nc\n" {
+		t.Errorf("%q", c.String())
+	}
+}