package middleware

import (
	"modelRT/util"

	"github.com/gin-gonic/gin"
)

// StartTrace define func of set trace info from request header
func StartTrace() gin.HandlerFunc {
	return func(c *gin.Context) {
		traceID := c.Request.Header.Get("traceid")
		pSpanID := c.Request.Header.Get("spanid")
		spanID := util.GenerateSpanID(c.Request.RemoteAddr)
		if traceID == "" { // 如果traceId 为空，证明是链路的发端，把它设置成此次的spanId，发端的spanId是root spanId
			traceID = spanID // trace 标识整个请求的链路, span则标识链路中的不同服务
		}
		c.Set("traceid", traceID)
		c.Set("spanid", spanID)
		c.Set("pspanid", pSpanID)
		c.Next()
	}
}