Game Backend Guide

Provide TCP or UDP Services

Additional ports can be configured in leanengine.yaml:

leanengine.yaml

extraPorts:
  - name: echo
    protocol: udp
    containerPort: 4000
  - name: game
    protocol: tcp
    containerPort: 4000

Up to 5 ports can be configured.

Connect From the Internet

You need to use the interface mentioned in the REST API section to get the IP and port to connect to from the Internet. You will then be able to connect from the client. We will use nc as an example:

$ nc -u 106.75.70.96 11348
hello
hello

Smooth Shutdown

In case of version updates, capacity adjustments or automatic system maintenance, your application process needs to be shut down. The Cloud Engine sends SIGTERM signals to your process and waits up to 60 minutes.

Your application should handle the SIGTERM signal (otherwise the default behavior is to exit immediately) and proactively exit as soon as possible based on business logic (e.g., whether there are still client connections).

func main() {
  go func() {
    sigTermChan := make(chan os.Signal, 1)
    signal.Notify(sigTermChan, syscall.SIGTERM, syscall.SIGINT)
    sig := <-sigTermChan

    log.Println("Received signal", sig)

    // Wait for existing business logic (e.g. client connection) to complete
    time.Sleep(60 * time.Second)

    // Proactively exit the program
    os.Exit(0)
  }()

  // Other code
}

If your application does not proactively exit within 60 minutes, the Cloud Engine will force your application to stop.

If more than 3 times the normal number of instances are in a graceful shutdown state (terminating), further deployments will fail and you will need to pass in an additional `forceStopOldInstances' option to force the earliest instances in a graceful shutdown state to shut down:

$ tds deploy --options 'forceStopOldInstances=true'

REST API

Interface	Authentication	Function
GET /1.1/engine/containers	Available to developers only	Get a list of running instances
GET /1.1/engine/gateway/route	Available to clients	Return connection information for a random instance

All interfaces require the X-LC-Id header, e.g. X-LC-Id: SJjoXHWuhewHKV4Ojw.

Developer-only interfaces require the access token in the Authorization header, e.g. Authorization: Bearer 14d1c1ff-908b-4a2c-baec-427cbde3bf05.

GET /containers

This interface returns a list of all running instances, and developers can implement custom routing logic based on this interface, such as assigning specific users to the same instance.

$ curl -H 'X-LC-Id: SJjoXHWuhewHKV4Ojw' \
       -H 'Authorization: Bearer 14d1c1ff-908b-4a2c-baec-427cbde3bf05'\
       'https://shared.cloud.tds1.tapapis.cn/1.1/engine/containers?groupName=udp&prod=1'

[
  {
    "name": "web3-219ebd3e",
    "prod": 1,
    "status": "running",
    "extraPorts": [
      {
        "name": "game",
        "protocol": "udp",
        "publicPort": 19766,
        "publicIp": "106.75.70.96"
      }
    ],
    "versionTag": "20220606-152341"
  },
  {
    "name": "web3-b102392b",
    "prod": 1,

    "createdAt": "2022-06-06T07:23:47.000Z",
    "forceStopAfter": "2022-06-06T07:24:27.000Z",

    "status": "terminating",
    "extraPorts": [
      {
        "name": "game",
        "protocol": "udp",
        "publicPort": 18288,
        "publicIp": "106.75.70.96"
      }
    ],
    "versionTag": "20220606-144209"
  }
]

The response will contain both running and terminated containers, where the extraPorts section is the external IP and port available for the endpoint to connect to.

GET /gateway/route

This interface does not require authentication and returns connection information for any running container for use directly on the client if the developer does not wish to develop the routing interface themselves.

$ curl -H 'X-LC-Id: SJjoXHWuhewHKV4Ojw' \
       'https://shared.cloud.tds1.tapapis.cn/1.1/engine/gateway/route?groupName=udp&prod=1'

[
  {
    "name": "game",
    "protocol": "udp",
    "publicPort": 19766,
    "publicIp": "106.75.70.96"
  }
]