We're happy to introduce a new major feature that may impact your Screeps gameplay in a whole new way: isolated virtual machine. We explained this a bit in this blog post earlier.

TL;DR:

• You can opt-in for an isolated VM in the new account settings UI called Runtime. This will move execution of your script to another pool of server nodes with this experimental feature enabled.

• In isolated VM you have your very own JavaScript environment, including heap memory and garbage collector.

• Since isolated VMs can be transferred between threads within the same Node.js process, it is no longer neccessary to maintain multiple global instances, you always have one single global.

• You can use new API method Game.cpu.getHeapStatistics() to know how much heap memory you're using in runtime. Maximum effective limit is 256 MB for each player.

Please note that this feature is still in development and considered experimental. Please report any incorrect behavior and be ready that things will be improved over time.

It seems like you currently need to save your code after switching to isolated mode, in order to force a code reload to the new virtual machine.

I already found a first bug, Game.shard seems to be undefined.

It seems like you currently need to save your code after switching to isolated mode, in order to force a code reload to the new virtual machine.

It should not be related. Are you sure it's not just coincidence?

I already found a first bug, Game.shard seems to be undefined.

Fixed, thanks.

Script execution timed out ungracefully, restarting virtual machine

Now I'm down to this and there are no ticks at all:

/* eslint-disable */
'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

function loop() {
    console.log("running");
}

exports.loop = loop;
//# sourceMappingURL=main.js.map

I'm sad to report that I'm unable to use it on PTR. With an empty main loop, no other files and empty Memory, it's still returning [3:56:35 AM][shard0]Script execution timed out ungracefully, restarting virtual machine.

minor nitpick, in the UI, the top right CPU/Memory might have some rounding issue. I'm seeing values like these: 60.799999999999955 / 290

[10:25:09 PM][shard0]RangeError: Array buffer allocation failed at new ArrayBuffer (<anonymous>) at typedArrayConstructByLength (<anonymous>) at new Float64Array (native) at new Heap (__runtime__:33218:27) at Object.findRoute (__runtime__:33024:13) at Object.findExit (__runtime__:33114:30) at Object.findExitTo (__runtime__:14667:29) at Object.findPathTo (__runtime__:14831:32) at Object.moveTo (__runtime__:36365:29)

@mrfaul the global still behaves like it did before, it can reset at any point. So think of it like ephemeral storage, it can be used, but don't solely rely on it for permanent data.

I think it would be nice if the whole memory was automatically cached to global in this case. You'd pay for the stringify at the end of the tick every time, but the parse should only be on a reset. If there's one global instance and this "just works" I think it should be in the backend rather than user-implemented.

let memory: any;
let lastTime: number = 0;

export function load_memory() {

  // const start = Game.cpu.getUsed();
  if (lastTime && memory && Game.time === (lastTime + 1)) {
    delete global.Memory;
    global.Memory = memory;
    RawMemory._parsed = memory;
    // console.log("Tick has same GID!");
  } else {
    // noinspection TsLint
    Memory.rooms;
    memory = RawMemory._parsed;
  }
  lastTime = Game.time;
  // const end = Game.cpu.getUsed();
  // console.log("memory loaded", lastTime, end - start);
}

this snippet is from slack, not sure who posted it ,) this also will work on the live server, when 2 ticks run on the same server, which happens quite often.

RangeError: Array buffer allocation failed
    at new ArrayBuffer ()
    at typedArrayConstructByLength ()
    at new Float64Array (native)
    at new Heap (:33344:27)
    // ======= ^ Screeps space
    at Object.findRoute (:33150:13)
    at Object.Creep.moveTo2 (__prototypes:1130:34)
    at Role.work (scout:179:27)
    at legacy_loop (main:1328:60)
    at LEGACY.run (main:1425:9)
    at Kernel:44:77
    // ======= ^ userspace

RangeError: Array buffer allocation failed
    at new ArrayBuffer ()
    at typedArrayConstructByLength ()
    at new Uint8Array (native)
    at new  (:39248:22)
    // ======= ^ Screeps space
    at staticRoomCallback (__prototypes:356:21)
    at global.civilRoomCallback (__prototypes:421:21)
    at roomCallback (__prototypes:1151:24)
    at :33018:31
    at Object.exports.search (:33030:19)
    at Object.search (:39286:38)
    // ======= ^ userspace

Moreover, sometimes V8 heap overflow errors appear unexpectedly, cannot track them for now.

I had the idea of giving bot creators a tool to create a binary of their bot's isolate snapshot that can be shared without publishing the source code. Currently bot publisher are trying to not publish a lot of offensive code, because it's going to be used on the official server, which in turn is hindering the experience of newer players. If this idea were to be implemented they could hold back parts of their code just like they do now, but publish the entire bot including military.

Actually implementing the upload and use of a binary snapshot can be taken care of by a mod, I'm just interested in whether we will get full isolated-vm support.

Bot snapshots is an interesting idea, but could be a bit tricky, since snapshots are architecture-dependent.

In order to switch your server to this experimental functionality, use beta prerelease tag:

npm install screeps@beta

Please note that some mods may become non-functional since playerSandbox event is not implemented yet.

It is recommended to set runners_cnt to 1 in your .screepsrc file, since otherwise it will create multiple global environments for each player. There is a new option runner_threads instead which should be set to the number of your CPU cores.