update logger

Closes #235

langserver/handle_workspace_did_change_configuration.go

@@ -3,6 +3,8 @@ package langserver
 import (
 	"context"
 	"encoding/json"
+	"log"
+	"os"
 	"time"
 
 	"github.com/sourcegraph/jsonrpc2"
@@ -44,5 +46,21 @@ func (h *langHandler) didChangeConfiguration(config *Config) (any, error) {
 		h.formatDebounce = time.Duration(config.FormatDebounce)
 	}
 
+	if config.LogFile != "" {
+		f, err := os.OpenFile(config.LogFile, os.O_CREATE|os.O_RDWR|os.O_APPEND, 0o660)
+		if err == nil {
+			if h.logger != nil {
+				if w, ok := h.logger.Writer().(*os.File); ok {
+					w.Close()
+				}
+			}
+			h.logger = log.New(f, "", log.LstdFlags)
+		}
+	}
+
+	if config.LogLevel > 0 {
+		h.loglevel = config.LogLevel
+	}
+
 	return nil, nil
 }