feat: improve error logging for token encoder initialization with offline usage guidance

Author: songquanpeng

relay/adaptor/openai/token.go

@@ -3,14 +3,16 @@ package openai
 import (
 	"errors"
 	"fmt"
+	"math"
+	"strings"
+
 	"github.com/pkoukk/tiktoken-go"
+
 	"github.com/songquanpeng/one-api/common/config"
 	"github.com/songquanpeng/one-api/common/image"
 	"github.com/songquanpeng/one-api/common/logger"
 	billingratio "github.com/songquanpeng/one-api/relay/billing/ratio"
 	"github.com/songquanpeng/one-api/relay/model"
-	"math"
-	"strings"
 )
 
 // tokenEncoderMap won't grow after initialization
@@ -21,7 +23,8 @@ func InitTokenEncoders() {
 	logger.SysLog("initializing token encoders")
 	gpt35TokenEncoder, err := tiktoken.EncodingForModel("gpt-3.5-turbo")
 	if err != nil {
-		logger.FatalLog(fmt.Sprintf("failed to get gpt-3.5-turbo token encoder: %s", err.Error()))
+		logger.FatalLog(fmt.Sprintf("failed to get gpt-3.5-turbo token encoder: %s, "+
+			"if you are using in offline environment, please set TIKTOKEN_CACHE_DIR to use exsited files, check this link for more information: https://stackoverflow.com/questions/76106366/how-to-use-tiktoken-in-offline-mode-computer ", err.Error()))
 	}
 	defaultTokenEncoder = gpt35TokenEncoder
 	gpt4oTokenEncoder, err := tiktoken.EncodingForModel("gpt-4o")