feat(swingset-vat): add xs-worker managerType

If any vats are configured to use it, but xs-vat-worker does not have
an executable to offer, swingset will throw an error. (IOU a test?)

 - Swingset package depends on xs-vat-worker
   - ISSUE: cycle. factor out liveslots?
 - add startXsWorker kernel endowment,
   which is undefined unless binary is built
 - parameterize execPath, args in startSubprocessWorker()
   (mantain previous defaults)
 - xs-vat-worker: adopt array style protocol from SwingSet (WIP)
   - based on subprocessSupervisor.js
     copied SwingSet/src/kernel/vatManager/subprocessSupervisor.js
     wholesale; applied ocap discipline to module-level mutable state;
     adapted IO interface. Compare:

Initially it would hang after the first 2 syscalls of the first
deliver:

 - [ 'subscribe', 'p-60' ]
 - [ 'subscribe', 'p-61' ]

Then I fixed handle() to return a promise in all cases to be sure to
finish delivery before next blocking read.

packages/SwingSet/package.json

@@ -39,6 +39,7 @@
     "@agoric/tame-metering": "^1.2.3",
     "@agoric/transform-eventual-send": "^1.3.1",
     "@agoric/transform-metering": "^1.3.0",
+    "@agoric/xs-vat-worker": "^0.1.0",
     "@babel/core": "^7.5.0",
     "@babel/generator": "^7.6.4",
     "anylogger": "^0.21.0",

packages/SwingSet/src/controller.js

@@ -16,6 +16,7 @@ import { importBundle } from '@agoric/import-bundle';
 import { initSwingStore } from '@agoric/swing-store-simple';
 import { makeMeteringTransformer } from '@agoric/transform-metering';
 import { makeTransform } from '@agoric/transform-eventual-send';
+import { xsWorkerBin } from '@agoric/xs-vat-worker';
 
 import { startSubprocessWorker } from './spawnSubprocessWorker';
 import { assertKnownOptions } from './assertOptions';
@@ -321,6 +322,10 @@ export async function buildVatController(
     // console.log(`--slog ${JSON.stringify(obj)}`);
   }
 
+  const startXsWorker = xsWorkerBin
+    ? () => startSubprocessWorker(xsWorkerBin, [])
+    : undefined;
+
   const kernelEndowments = {
     waitUntilQuiescent,
     hostStorage,
@@ -333,6 +338,7 @@ export async function buildVatController(
     makeNodeWorker,
     startSubprocessWorker,
     writeSlogObject,
+    startXsWorker,
   };
 
   const kernelOptions = { verbose };

packages/SwingSet/src/kernel/kernel.js

@@ -52,6 +52,7 @@ export default function buildKernel(kernelEndowments, kernelOptions = {}) {
     makeNodeWorker,
     startSubprocessWorker,
     writeSlogObject,
+    startXsWorker,
   } = kernelEndowments;
   const { verbose } = kernelOptions;
   const logStartup = verbose ? console.debug : () => 0;
@@ -613,6 +614,7 @@ export default function buildKernel(kernelEndowments, kernelOptions = {}) {
     waitUntilQuiescent,
     makeNodeWorker,
     startSubprocessWorker,
+    startXsWorker,
   });
 
   function buildVatSyscallHandler(vatID, translators) {

packages/SwingSet/src/kernel/vatManager/factory.js

@@ -14,6 +14,7 @@ export function makeVatManagerFactory({
   waitUntilQuiescent,
   makeNodeWorker,
   startSubprocessWorker,
+  startXsWorker,
 }) {
   const localFactory = makeLocalVatManagerFactory({
     allVatPowers,
@@ -34,6 +35,11 @@ export function makeVatManagerFactory({
     kernelKeeper,
   });
 
+  const xsWorkerFactory = makeNodeSubprocessFactory({
+    startSubprocessWorker: startXsWorker,
+    kernelKeeper,
+  });
+
   function validateManagerOptions(managerOptions) {
     assertKnownOptions(managerOptions, [
       'enablePipelining',
@@ -93,6 +99,13 @@ export function makeVatManagerFactory({
       );
     }
 
+    if (managerType === 'xs-worker') {
+      if (!xsWorkerFactory) {
+        throw new Error('manager type xs-worker not available');
+      }
+      return xsWorkerFactory.createFromBundle(vatID, bundle, managerOptions);
+    }
+
     throw Error(
       `unknown type ${managerType}, not local/nodeWorker/node-subprocess`,
     );

packages/SwingSet/src/spawnSubprocessWorker.js

@@ -20,8 +20,10 @@ const supercode = require.resolve(
 // always be Node.
 const stdio = harden(['inherit', 'inherit', 'inherit', 'pipe', 'pipe']);
 
-export function startSubprocessWorker() {
-  const proc = spawn(process.execPath, ['-r', 'esm', supercode], { stdio });
+export function startSubprocessWorker(execPath, args) {
+  execPath = execPath || process.execPath;
+  args = args || ['-r', 'esm', supercode];
+  const proc = spawn(execPath, args, { stdio });
 
   const toChild = Netstring.writeStream();
   toChild.pipe(proc.stdio[3]);

packages/SwingSet/test/workers/test-worker.js

@@ -1,7 +1,25 @@
 import '@agoric/install-ses';
 import test from 'ava';
+import { xsWorkerBin } from '@agoric/xs-vat-worker/src/locate';
 import { loadBasedir, buildVatController } from '../../src/index';
 
+test('xs vat manager', async t => {
+  if (!xsWorkerBin) {
+    console.warn('XS vat worker not built; skipping');
+    t.falsy.skip(false);
+    return;
+  }
+
+  const config = await loadBasedir(__dirname);
+  config.vats.target.creationOptions = { managerType: 'xs-worker' };
+  const c = await buildVatController(config, []);
+
+  await c.run();
+  t.is(c.bootstrapResult.status(), 'fulfilled');
+
+  await c.shutdown();
+});
+
 test('nodeWorker vat manager', async t => {
   const config = await loadBasedir(__dirname);
   config.vats.target.creationOptions = { managerType: 'nodeWorker' };

packages/xs-vat-worker/package.json

@@ -34,6 +34,7 @@
     "@agoric/eventual-send": "^0.9.3",
     "@agoric/import-bundle": "^0.0.8",
     "@agoric/install-ses": "^0.2.0",
+    "@agoric/marshal": "^0.2.3",
     "@agoric/promise-kit": "^0.1.3",
     "@agoric/swingset-vat": "^0.6.0",
     "anylogger": "^1.0.4",