refactor: don't make METER_TYPE a manifest constant

Instead, attach the actual value to the meterUsage/crankStats
record, since that is the most likely place that will change what
it means.

Author: michaelfig

packages/SwingSet/src/kernel/metering.js

@@ -39,17 +39,19 @@ export function makeMeterManager(replaceGlobalMeter) {
       // console.error(`-- METER REFILL`);
       // console.error(`   allocate used: ${FULL - refillFacet.getAllocateBalance()}`);
       // console.error(`   compute used : ${FULL - refillFacet.getComputeBalance()}`);
-      const used = harden({
+      const meterUsage = harden({
+        // TODO: Change this meterType whenever the semantics change.
+        meterType: 'tame-metering-1',
         allocate: FULL - refillFacet.getAllocateBalance(),
         compute: FULL - refillFacet.getComputeBalance(),
       });
       if (meter.isExhausted() && !refillIfExhausted) {
-        return used;
+        return meterUsage;
       }
       refillFacet.allocate();
       refillFacet.compute();
       refillFacet.stack();
-      return used;
+      return meterUsage;
     }
 
     if (refillEachCrank) {

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

@@ -1,7 +1,6 @@
 import { assert, details as X } from '@agoric/assert';
 import { insistMessage } from '../../message';
 
-const METER_TYPE = 'tame-metering-1';
 export function makeDeliver(tools, dispatch) {
   const {
     meterRecord,
@@ -56,11 +55,13 @@ export function makeDeliver(tools, dispatch) {
     // refill this vat's meter, if any, accumulating its usage for stats
     if (meterRecord) {
       // note that refill() won't actually refill an exhausted meter
-      status[2] = { ...meterRecord.refill(), meterType: METER_TYPE };
+      const meterUsage = meterRecord.refill();
       const exhaustionError = meterRecord.isExhausted();
       if (exhaustionError) {
-        status = ['error', exhaustionError.message, status[2]];
+        status = ['error', exhaustionError.message, meterUsage];
       } else {
+        // We will have ['ok', null, meterUsage]
+        status[2] = meterUsage;
         updateStats(status[2]);
       }
     }

packages/cosmic-swingset/lib/kernel-stats.js

@@ -117,25 +117,30 @@ export function makeSlogCallbacks({ metricMeter, labels }) {
       });
     },
     delivery(_method, [vatID], finisher) {
-      return wrapDeltaMS(finisher, (deltaMS, [[_status, _problem, usage]]) => {
-        getGroupedMetric('swingset_vat_delivery', { vatID }).record(deltaMS);
-        if (usage) {
-          // Add to aggregated metering stats.
-          const group = { vatID };
-          for (const [key, value] of Object.entries(usage)) {
-            if (key === 'meterType') {
-              // eslint-disable-next-line no-continue
-              continue;
+      return wrapDeltaMS(
+        finisher,
+        (deltaMS, [[_status, _problem, meterUsage]]) => {
+          getGroupedMetric('swingset_vat_delivery', { vatID }).record(deltaMS);
+          if (meterUsage) {
+            // Add to aggregated metering stats.
+            const group = { vatID };
+            for (const [key, value] of Object.entries(meterUsage)) {
+              if (key === 'meterType') {
+                // eslint-disable-next-line no-continue
+                continue;
+              }
+              getGroupedMetric(`swingset_meter_usage`, group, {
+                // The meterType is an instance-specific label--a change in it
+                // will result in the old value being discarded.
+                ...(meterUsage.meterType && {
+                  meterType: meterUsage.meterType,
+                }),
+                stat: key,
+              }).record(value || 0);
             }
-            getGroupedMetric(`swingset_meter_usage`, group, {
-              // The meterType is an instance-specific label--a change in it
-              // will result in the old value being discarded.
-              ...(usage.meterType && { meterType: usage.meterType }),
-              stat: key,
-            }).record(value || 0);
           }
-        }
-      });
+        },
+      );
     },
   };
 

packages/xsnap/src/xsnap.js

@@ -18,10 +18,6 @@ import * as node from './node-stream';
 // This will need adjustment, but seems to be fine for a start.
 const DEFAULT_CRANK_METERING_LIMIT = 1e7;
 
-// The version identifier for our meter type.
-// TODO Bump this whenever there's a change to metering semantics.
-const METER_TYPE = 'xs-meter-1';
-
 const OK = '.'.charCodeAt(0);
 const ERROR = '!'.charCodeAt(0);
 const QUERY = '?'.charCodeAt(0);
@@ -155,7 +151,9 @@ export function xsnap(options) {
           compute = JSON.parse(decoder.decode(meterData));
         }
         const crankStats = {
-          meterType: METER_TYPE,
+          // The version identifier for our meter type.
+          // TODO Bump this whenever there's a change to metering semantics.
+          meterType: 'xs-meter-1',
           allocate: null, // No allocation meter yet.
           compute,
         };