only sanitize the event if it is actually going to be logged

handle.go

@@ -91,7 +91,7 @@ func CreateHttpHandler(handlers Handlers) func(http.ResponseWriter, *http.Reques
 		start := time.Now()
 		logger.Debugf("Skill execution started")
 		if req.Event.Type != "sync-request" {
-			logger.Debugf("Incoming event message: %s", sanitizeEvent(body))
+			logger.Debugf("Incoming event message: %s", func() interface{} { return sanitizeEvent(body) })
 		}
 
 		defer func() {

log.go

@@ -147,6 +147,7 @@ func createLogger(ctx context.Context, event EventIncoming, headers http.Header)
 		doGcpLog(msg, internal.Debug)
 	}
 	logger.Debugf = func(format string, a ...any) {
+		a = expandFuncs(a, logrus.DebugLevel)
 		Log.WithFields(localLabels).Debugf(format, a...)
 		doGcpLog(fmt.Sprintf(format, a...), internal.Debug)
 	}
@@ -185,6 +186,16 @@ func createLogger(ctx context.Context, event EventIncoming, headers http.Header)
 	return logger
 }
 
+func expandFuncs(a []any, level logrus.Level) []any {
+	for i, v := range a {
+		if f, ok := v.(func() interface{}); ok && Log.Level >= level {
+			a[i] = f()
+		}
+	}
+
+	return a
+}
+
 // SanitizeEvent removes any sensitive information from the incoming payload structure
 func sanitizeEvent(incoming string) string {
 	re, _ := regexp.Compile(`:([a-z\.\/-]*)\s*"(.*?)"`)

log_test.go

@@ -17,13 +17,15 @@
 package skill
 
 import (
+	"bytes"
 	"context"
 	"net/http"
 	"net/http/httptest"
 	"strings"
 	"testing"
 
 	"github.com/atomist-skills/go-skill/internal"
+	"github.com/sirupsen/logrus"
 
 	"olympos.io/encoding/edn"
 )
@@ -91,3 +93,15 @@ func TestSanitizeEventWithSingleCharacterUser(t *testing.T) {
 		t.Errorf("user not sanitised")
 	}
 }
+
+func TestLoggingWithFunc(t *testing.T) {
+	var buf bytes.Buffer
+	Log.SetOutput(&buf)
+	Log.SetLevel(logrus.DebugLevel)
+	logger := createLogger(context.Background(), EventIncoming{}, http.Header{})
+	logger.Debugf("This is a %s message", func() interface{} { return "test" })
+
+	if !strings.Contains(buf.String(), "This is a test message") {
+		t.Errorf("Expected message not found")
+	}
+}