Automatic client-side balancing

[dev-kick]

Hello developers!

I would really like to implement automatic client-side balancing, since it is extremely convenient for automatically selecting the server with the best latency/ping for the user.

However, currently this is difficult to achieve because:

1. Generated outbounds always use a fixed tag:

"tag": "proxy"

This makes it impossible to use Xray balancers properly, because each outbound must have a unique tag.

2. When adding multiple custom outbounds in client templates, the vnext.users section is not populated automatically with user UUID, which makes such configs unusable.

As an example, this is the type of balancing configuration I would like to build:

{
  "outbounds": [
    {
      "tag": "node-1",
      "protocol": "vless",
      "settings": {
        "vnext": [
          {
            "address": "1.1.1.1",
            "port": 443,
            "users": [
              {
                "id": "UUID",
                "encryption": "none",
                "flow": "xtls-rprx-vision"
              }
            ]
          }
        ]
      },
      "streamSettings": {
        "network": "tcp",
        "security": "reality",
        "realitySettings": {
          "serverName": "example.com",
          "publicKey": "PUBLIC_KEY",
          "shortId": "SHORT_ID",
          "fingerprint": "chrome"
        }
      }
    },
    {
      "tag": "node-2",
      "protocol": "vless",
      "settings": {
        "vnext": [
          {
            "address": "2.2.2.2",
            "port": 443,
            "users": [
              {
                "id": "UUID",
                "encryption": "none",
                "flow": "xtls-rprx-vision"
              }
            ]
          }
        ]
      },
      "streamSettings": {
        "network": "tcp",
        "security": "reality",
        "realitySettings": {
          "serverName": "example.com",
          "publicKey": "PUBLIC_KEY",
          "shortId": "SHORT_ID",
          "fingerprint": "chrome"
        }
      }
    }
  ],
  "routing": {
    "balancers": [
      {
        "tag": "proxy-balance",
        "selector": [
          "node-1",
          "node-2"
        ],
        "strategy": {
          "type": "roundRobin"
        }
      }
    ],
    "rules": [
      {
        "type": "field",
        "network": "tcp,udp",
        "balancerTag": "proxy-balance"
      }
    ]
  }
}

Would it be possible to implement automatic generation of unique outbound tags for balancing purposes?

Or alternatively, allow vnext.users to be used in custom templates, for example:

"users": [
  {
    "id": "{{uuid}}",
    "encryption": "none",
    "flow": "xtls-rprx-vision"
  }
]

This would make it possible to build advanced client-side balancing configurations using Xray balancers, observatory, and leastPing.

Thank you!