code: func (ctx *Context) GetComponentAccessToken() (string, error) {
  	accessTokenCacheKey := fmt.Sprintf("component_access_token_%s", ctx.AppID)
  	val := ctx.Cache.Get(accessTokenCacheKey)
  	if val == nil {
  		return "", fmt.Errorf("cann't get component access token")
  	}
  	return val.(string), nil
  }
docs: // GetComponentAccessToken 获取 ComponentAccessToken