Add ability to request stats for a Vat.

packages/SwingSet/src/kernel/kernel.js

@@ -618,6 +618,12 @@ export default function buildKernel(kernelEndowments) {
     );
   }
 
+  function collectVatStats(vatID) {
+    insistVatID(vatID);
+    const vatManager = ephemeral.vats.get(vatID).manager;
+    return vatManager.vatStats();
+  }
+
   async function start(bootstrapVatName, argvString) {
     if (started) {
       throw new Error('kernel.start already called');
@@ -656,7 +662,11 @@ export default function buildKernel(kernelEndowments) {
     if (vatAdminDevSetup) {
       const params = {
         setup: vatAdminDevSetup,
-        endowments: { create: createVatDynamically /* vatStats, terminate */ },
+        endowments: {
+          create: createVatDynamically,
+          stats: collectVatStats,
+          /* terminate */
+        },
       };
       genesisDevices.set('vatAdmin', params);
     }

packages/SwingSet/src/kernel/state/vatKeeper.js

@@ -7,11 +7,17 @@ import { insistVatID } from '../id';
 
 // makeVatKeeper is a pure function: all state is kept in the argument object
 
+// TODO: tests rely on these numbers and haven't been updated to use names.
+const FIRST_OBJECT_ID = 50;
+const FIRST_PROMISE_ID = 60;
+const FIRST_DEVICE_ID = 70;
+const FIRST_TRANSCRIPT_ID = 0;
+
 export function initializeVatState(storage, vatID) {
-  storage.set(`${vatID}.o.nextID`, '50');
-  storage.set(`${vatID}.p.nextID`, '60');
-  storage.set(`${vatID}.d.nextID`, '70');
-  storage.set(`${vatID}.t.nextID`, '0');
+  storage.set(`${vatID}.o.nextID`, `${FIRST_OBJECT_ID}`);
+  storage.set(`${vatID}.p.nextID`, `${FIRST_PROMISE_ID}`);
+  storage.set(`${vatID}.d.nextID`, `${FIRST_DEVICE_ID}`);
+  storage.set(`${vatID}.t.nextID`, `${FIRST_TRANSCRIPT_ID}`);
 }
 
 export function makeVatKeeper(
@@ -101,6 +107,20 @@ export function makeVatKeeper(
     storage.set(`${vatID}.t.${id}`, JSON.stringify(msg));
   }
 
+  function vatStats() {
+    const objectCount = storage.get(`${vatID}.o.nextID`) - FIRST_OBJECT_ID;
+    const promiseCount = storage.get(`${vatID}.p.nextID`) - FIRST_PROMISE_ID;
+    const deviceCount = storage.get(`${vatID}.d.nextID`) - FIRST_DEVICE_ID;
+    const transcriptCount =
+      storage.get(`${vatID}.t.nextID`) - FIRST_TRANSCRIPT_ID;
+    return harden({
+      objectCount: Nat(Number(objectCount)),
+      promiseCount: Nat(Number(promiseCount)),
+      deviceCount: Nat(Number(deviceCount)),
+      transcriptCount: Nat(Number(transcriptCount)),
+    });
+  }
+
   // pretty print for logging and testing
   function dumpState() {
     const res = [];
@@ -123,6 +143,7 @@ export function makeVatKeeper(
     mapKernelSlotToVatSlot,
     getTranscript,
     addToTranscript,
+    vatStats,
     dumpState,
   });
 }

packages/SwingSet/src/kernel/vatAdmin/vatAdmin-src.js

@@ -10,10 +10,9 @@ import harden from '@agoric/harden';
  * root device. Selected vats that need to create new vats can be given access
  * to the device.
  *
- * This code runs in the inner part of the device vat. It handles kernel objects
- * in serialized format, and can use SO() to send messages to them. The only
- * device object exposed to vats is the vat creator. The root objects for the
- * new vats are returned as javascript objects.
+ * This code runs in the inner part of the device vat. The only device object
+ * exposed to vats is the vat creator. The root objects for the new vats are
+ * returned as javascript objects.
  *
  * We don't currently need to use SO, or to maintain state. All functionality is
  * provided by calling kernel functions and passing in the VatID. The wrapper
@@ -22,32 +21,28 @@ import harden from '@agoric/harden';
 export default function setup(syscall, state, helpers, endowments) {
   const {
     create: kernelVatCreationFn,
-    // stats: kernelVatStatsFn,
+    stats: kernelVatStatsFn,
     // terminate: kernelTerminateFn,
   } = endowments;
 
-  // call the registered kernel function to create a new vat, and receive a
-  // vatId in return. Clean up the outgoing and incoming arguments.
-  function callKernelVatCreation(src) {
-    return kernelVatCreationFn(`${src}`);
-  }
-
-  // makeRootDevice is called with { _SO, _getDeviceState, _setDeviceState } as
-  // a parameter, but we don't need these, as discussed above.
+  // makeRootDevice is called with { SO, getDeviceState, setDeviceState } as
+  // parameters, but we don't need these, as discussed above.
   function makeRootDevice() {
     // The Root Device Node.
     return harden({
       // Called by the wrapper vat to create a new vat. Gets a new ID from the
       // kernel's vat creator fn. Remember that the root object will arrive
-      // separately.
+      // separately. Clean up the outgoing and incoming arguments.
       create(code) {
-        return callKernelVatCreation(code);
+        return kernelVatCreationFn(`${code}`);
       },
       terminate(_vatID) {
         // TODO(hibbert)
       },
-      adminStats(_vatID) {
-        // TODO(hibbert)
+      // Call the registered kernel function to request vat stats. Clean up the
+      // outgoing and incoming arguments.
+      adminStats(vatID) {
+        return kernelVatStatsFn(`${vatID}`);
       },
     });
   }

packages/SwingSet/src/kernel/vatManager.js

@@ -288,6 +288,10 @@ export default function makeVatManager(
     );
   }
 
+  function vatStats() {
+    return vatKeeper.vatStats();
+  }
+
   async function deliverOneMessage(target, msg) {
     insistMessage(msg);
     const targetSlot = mapKernelSlotToVatSlot(target);
@@ -385,6 +389,7 @@ export default function makeVatManager(
     deliverOneMessage,
     deliverOneNotification,
     replayTranscript,
+    vatStats,
   };
   return manager;
 }

packages/SwingSet/test/vat-admin/bootstrap.js

@@ -81,6 +81,16 @@ export default function setup(syscall, state, helpers) {
               log(await E(vatAdminSvc).createVat(src));
               return;
             }
+            case 'vatStats': {
+              log(`starting stats test`);
+              const src = `${serviceHolder.build}`;
+              const vatAdminSvc = await E(vats.vatAdmin).createVatAdminService(
+                devices.vatAdmin,
+              );
+              const { adminNode } = await E(vatAdminSvc).createVat(src);
+              log(await E(adminNode).adminData());
+              return;
+            }
             default:
               throw new Error(`unknown argv mode '${argv[0]}'`);
           }

packages/SwingSet/test/vat-admin/test-innerVat.js

@@ -68,3 +68,22 @@ test('VatAdmin broken vat creation', async t => {
 test('VatAdmin broken vat creation non-SES', async t => {
   await testBrokenVatCreation(t, false);
 });
+
+async function testGetVatStats(t, withSES) {
+  const config = await createConfig();
+  const c = await buildVatController(config, withSES, ['vatStats']);
+  await c.run();
+  t.deepEqual(c.dump().log, [
+    'starting stats test',
+    '{"objectCount":0,"promiseCount":0,"deviceCount":0,"transcriptCount":0}',
+  ]);
+  t.end();
+}
+
+test('VatAdmin get vat stats', async t => {
+  await testGetVatStats(t, true);
+});
+
+test('VatAdmin get vat stats non-SES', async t => {
+  await testGetVatStats(t, false);
+});