feat!: make Treasury use ParamManagers for loan & fee parameters

packages/governance/src/exported.js

@@ -0,0 +1 @@
+import './types';

packages/treasury/package.json

@@ -37,6 +37,7 @@
     "@agoric/deploy-script-support": "^0.2.9",
     "@agoric/ertp": "^0.11.2",
     "@agoric/eventual-send": "^0.13.14",
+    "@agoric/governance": "^0.1.0",
     "@agoric/marshal": "^0.4.11",
     "@agoric/nat": "^4.0.0",
     "@agoric/notifier": "^0.3.14",

packages/treasury/src/paramKeys.js

@@ -0,0 +1,13 @@
+// @ts-check
+
+export const POOL_FEE_KEY = 'poolFee';
+export const PROTOCOL_FEE_KEY = 'protocolFee';
+
+export const CHARGING_PERIOD_KEY = 'chargingPeriod';
+export const RECORDING_PERIOD_KEY = 'recordingPeriod';
+
+export const INITIAL_MARGIN_KEY = 'initialMargin';
+export const LIQUIDATION_MARGIN_KEY = 'liquidationMargin';
+export const INITIAL_PRICE_KEY = 'initialPrice';
+export const INTEREST_RATE_KEY = 'interestRate';
+export const LOAN_FEE_KEY = 'loanFee';

packages/treasury/src/stablecoinMachine.js

@@ -2,6 +2,7 @@
 
 import '@agoric/zoe/exported';
 import '@agoric/zoe/src/contracts/exported';
+import '@agoric/governance/src/exported';
 
 // The StableCoinMachine owns a number of VaultManagers, and a mint for the
 // "RUN" stablecoin. This overarching SCM will hold ownershipTokens in the
@@ -32,10 +33,26 @@ import {
   makeRatioFromAmounts,
 } from '@agoric/zoe/src/contractSupport/ratio';
 import { AmountMath } from '@agoric/ertp';
+import {
+  buildParamManager,
+  ParamType,
+} from '@agoric/governance/src/param-manager';
+
 import { makeTracer } from './makeTracer';
 import { makeVaultManager } from './vaultManager';
 import { makeLiquidationStrategy } from './liquidateMinimum';
 import { makeMakeCollectFeesInvitation } from './collectRewardFees';
+import {
+  PROTOCOL_FEE_KEY,
+  POOL_FEE_KEY,
+  RECORDING_PERIOD_KEY,
+  CHARGING_PERIOD_KEY,
+  INITIAL_MARGIN_KEY,
+  LIQUIDATION_MARGIN_KEY,
+  INITIAL_PRICE_KEY,
+  INTEREST_RATE_KEY,
+  LOAN_FEE_KEY,
+} from './paramKeys';
 
 const trace = makeTracer('ST');
 
@@ -64,6 +81,22 @@ export async function start(zcf) {
     )}) must be a BigInt`,
   );
 
+  const {
+    publicFacet: paramManagerPublic,
+    manager: paramManager,
+  } = buildParamManager([
+    {
+      name: POOL_FEE_KEY,
+      value: loanParams.poolFee,
+      type: ParamType.BIGINT,
+    },
+    {
+      name: PROTOCOL_FEE_KEY,
+      value: loanParams.protocolFee,
+      type: ParamType.BIGINT,
+    },
+  ]);
+
   const [runMint, govMint] = await Promise.all([
     zcf.makeZCFMint('RUN', undefined, harden({ decimalPlaces: 6 })),
     zcf.makeZCFMint('Governance', undefined, harden({ decimalPlaces: 6 })),
@@ -114,11 +147,15 @@ export async function start(zcf) {
     { Central: runIssuer },
     {
       timer: timerService,
-      poolFee: loanParams.poolFee,
-      protocolFee: loanParams.protocolFee,
+      // TODO(hibbert): make the AMM use a paramManager. For now, the values
+      //  are fixed after creation of an autoswap instance.
+      poolFee: paramManagerPublic.lookup(POOL_FEE_KEY),
+      protocolFee: paramManagerPublic.lookup(PROTOCOL_FEE_KEY),
     },
   );
 
+  const rateManagers = makeStore('brand'); // Brand -> rateManager
+
   // We process only one offer per collateralType. They must tell us the
   // dollar value of their collateral, and we create that many RUN.
   // collateralKeyword = 'aEth'
@@ -131,6 +168,49 @@ export async function start(zcf) {
     const collateralBrand = zcf.getBrandForIssuer(collateralIssuer);
     assert(!collateralTypes.has(collateralBrand));
 
+    const {
+      publicFacet: rateManagerPublic,
+      manager: rateManager,
+    } = buildParamManager([
+      {
+        name: CHARGING_PERIOD_KEY,
+        value: loanParams.chargingPeriod,
+        type: ParamType.BIGINT,
+      },
+      {
+        name: RECORDING_PERIOD_KEY,
+        value: loanParams.recordingPeriod,
+        type: ParamType.BIGINT,
+      },
+      {
+        name: INITIAL_MARGIN_KEY,
+        value: rates.initialMargin,
+        type: ParamType.RATIO,
+      },
+      {
+        name: LIQUIDATION_MARGIN_KEY,
+        value: rates.liquidationMargin,
+        type: ParamType.RATIO,
+      },
+      {
+        name: INITIAL_PRICE_KEY,
+        value: rates.initialPrice,
+        type: ParamType.RATIO,
+      },
+      {
+        name: INTEREST_RATE_KEY,
+        value: rates.interestRate,
+        type: ParamType.RATIO,
+      },
+      {
+        name: LOAN_FEE_KEY,
+        value: rates.loanFee,
+        type: ParamType.RATIO,
+      },
+    ]);
+    assert(!rateManagers.has(collateralBrand));
+    rateManagers.init(collateralBrand, rateManager);
+
     const { creatorFacet: liquidationFacet } = await E(zoe).startInstance(
       liquidationInstall,
       { RUN: runIssuer },
@@ -147,7 +227,8 @@ export async function start(zcf) {
         want: { Governance: _govOut }, // ownership of the whole stablecoin machine
       } = seat.getProposal();
       assert(!collateralTypes.has(collateralBrand));
-      const runAmount = multiplyBy(collateralIn, rates.initialPrice);
+      const initialPrice = rateManagerPublic.lookup(INITIAL_PRICE_KEY);
+      const runAmount = multiplyBy(collateralIn, initialPrice);
       // arbitrarily, give governance tokens equal to RUN tokens
       const govAmount = AmountMath.make(runAmount.value, govBrand);
 
@@ -223,10 +304,10 @@ export async function start(zcf) {
         runMint,
         collateralBrand,
         priceAuthority,
-        rates,
+        rateManagerPublic,
         reallocateReward,
         timerService,
-        loanParams,
+        paramManagerPublic,
         liquidationStrategy,
       );
       collateralTypes.init(collateralBrand, vm);
@@ -318,8 +399,6 @@ export async function start(zcf) {
     return getBootstrapPayment;
   }
 
-  const getBootstrapPayment = mintBootstrapPayment();
-
   const publicFacet = harden({
     getAMM() {
       return autoswapInstance;
@@ -331,6 +410,7 @@ export async function start(zcf) {
     getRunIssuer() {
       return runIssuer;
     },
+    getParamManager: () => paramManagerPublic,
   });
 
   const { makeCollectFeesInvitation } = makeMakeCollectFeesInvitation(
@@ -348,8 +428,10 @@ export async function start(zcf) {
     },
     getCollaterals,
     getRewardAllocation,
-    getBootstrapPayment,
+    getBootstrapPayment: mintBootstrapPayment(),
     makeCollectFeesInvitation,
+    getParamManager: () => paramManager,
+    getRateManager: rateManagers.get,
   });
 
   return harden({ creatorFacet: stablecoinMachine, publicFacet });

packages/treasury/src/types.js

@@ -32,6 +32,9 @@
  * @property {(collateralIssuer: Issuer, collateralKeyword: Keyword, rates: Rates) => Promise<Invitation>} makeAddTypeInvitation
  * @property {() => Instance} getAMM
  * @property {() => Promise<Array<Collateral>>} getCollaterals
+ * @property {() => Payment} getBootstrapPayment
+ * @property {() => ParamManager} paramManager
+ * @property {() => ParamManager} getRateManager
  */
 
 /**
@@ -65,6 +68,10 @@
  * @property {() => Promise<PriceQuote>} getCollateralQuote
  * @property {() => Ratio} getInitialMargin
  * @property {() => Ratio} getInterestRate - The annual interest rate on a loan
+ * @property {() => RelativeTime} getChargingPeriod - The period (in seconds) at
+ *   which interest is charged to the loan.
+ * @property {() => RelativeTime} getRecordingPeriod - The period (in seconds)
+ *   at which interest is recorded to the loan.
  * @property {ReallocateReward} reallocateReward
  */
 
@@ -113,6 +120,12 @@
  * @property {RelativeTime} recordingPeriod
  */
 
+/**
+ * @typedef {Object} AMMFees
+ * @property {bigint} poolFee
+ * @property {bigint} protocolFee
+ */
+
 /**
  * @typedef {Object} LiquidationStrategy
  * @property {() => KeywordKeywordRecord} keywordMapping
@@ -127,10 +140,10 @@
  * @param {ZCFMint} runMint
  * @param {Brand} collateralBrand
  * @param {ERef<PriceAuthority>} priceAuthority
- * @param {Rates} rates
- * @param {StageReward} rewardPoolStaging
+ * @param {ParamManagerPublic} rateManager
+ * @param {ReallocateReward} reallocateReward
  * @param {TimerService} timerService
- * @param {LoanParams} loanParams
+ * @param {ParamManagerPublic} paramManager
  * @param {LiquidationStrategy} liquidationStrategy
  * @returns {VaultManager}
  */
@@ -142,7 +155,7 @@
  * @param {ZCFMint} runMint
  * @param {ERef<MultipoolAutoswapPublicFacet>} autoswap
  * @param {ERef<PriceAuthority>} priceAuthority
- * @param {LoanParams} loanParams
+ * @param {ParamManagerPublic} paramManager
  * @param {Timestamp} startTimeStamp
  * @returns {VaultKit}
  */

packages/treasury/src/vault.js

@@ -27,7 +27,7 @@ export function makeVaultKit(
   runMint,
   autoswap,
   priceAuthority,
-  loanParams,
+  loanParamManager,
   startTimeStamp,
 ) {
   const trace = makeTracer('VV');
@@ -57,8 +57,8 @@ export function makeVaultKit(
   const interestCalculator = makeInterestCalculator(
     runBrand,
     manager.getInterestRate(),
-    loanParams.chargingPeriod,
-    loanParams.recordingPeriod,
+    manager.getChargingPeriod(),
+    manager.getRecordingPeriod(),
   );
 
   function getCollateralAllocated(seat) {

packages/treasury/src/vaultManager.js

@@ -17,6 +17,14 @@ import { makeVaultKit } from './vault';
 import { makePrioritizedVaults } from './prioritizedVaults';
 import { liquidate } from './liquidation';
 import { makeTracer } from './makeTracer';
+import {
+  RECORDING_PERIOD_KEY,
+  LIQUIDATION_MARGIN_KEY,
+  INITIAL_MARGIN_KEY,
+  LOAN_FEE_KEY,
+  INTEREST_RATE_KEY,
+  CHARGING_PERIOD_KEY,
+} from './paramKeys';
 
 const trace = makeTracer(' VM ');
 
@@ -32,28 +40,34 @@ export function makeVaultManager(
   runMint,
   collateralBrand,
   priceAuthority,
-  rates,
+  rateManager,
   reallocateReward,
   timerService,
-  loanParams,
+  loanParamManager,
   liquidationStrategy,
 ) {
   const { brand: runBrand } = runMint.getIssuerRecord();
 
   const shared = {
     // loans below this margin may be liquidated
     getLiquidationMargin() {
-      return rates.liquidationMargin;
+      return rateManager.lookup(LIQUIDATION_MARGIN_KEY);
     },
     // loans must initially have at least 1.2x collateralization
     getInitialMargin() {
-      return rates.initialMargin;
+      return rateManager.lookup(INITIAL_MARGIN_KEY);
     },
     getLoanFee() {
-      return rates.loanFee;
+      return rateManager.lookup(LOAN_FEE_KEY);
     },
     getInterestRate() {
-      return rates.interestRate;
+      return rateManager.lookup(INTEREST_RATE_KEY);
+    },
+    getChargingPeriod() {
+      return rateManager.lookup(CHARGING_PERIOD_KEY);
+    },
+    getRecordingPeriod() {
+      return rateManager.lookup(RECORDING_PERIOD_KEY);
     },
     async getCollateralQuote() {
       // get a quote for one unit of the collateral
@@ -174,7 +188,7 @@ export function makeVaultManager(
 
   const periodNotifier = E(timerService).makeNotifier(
     0n,
-    loanParams.recordingPeriod,
+    rateManager.lookup(RECORDING_PERIOD_KEY),
   );
   const { zcfSeat: poolIncrementSeat } = zcf.makeEmptySeatKit();
 
@@ -211,7 +225,7 @@ export function makeVaultManager(
       runMint,
       autoswap,
       priceAuthority,
-      loanParams,
+      loanParamManager,
       startTimeStamp,
     );
 

packages/treasury/test/test-bootstrapPayment.js

@@ -35,6 +35,8 @@ test('bootstrap payment', async t => {
   const loanParams = {
     chargingPeriod: 2n,
     recordingPeriod: 10n,
+    poolFee: 24n,
+    protocolFee: 6n,
   };
   const manualTimer = buildManualTimer(console.log);
   // This test value is not a statement about the actual value to
@@ -81,6 +83,8 @@ test('bootstrap payment - only minted once', async t => {
   const loanParams = {
     chargingPeriod: 2n,
     recordingPeriod: 10n,
+    poolFee: 24n,
+    protocolFee: 6n,
   };
   const manualTimer = buildManualTimer(console.log);
   // This test value is not a statement about the actual value to
@@ -136,6 +140,8 @@ test('bootstrap payment - default value is 0n', async t => {
   const loanParams = {
     chargingPeriod: 2n,
     recordingPeriod: 10n,
+    poolFee: 24n,
+    protocolFee: 6n,
   };
   const manualTimer = buildManualTimer(console.log);
   const { creatorFacet: stablecoinMachine, instance } = await E(

packages/treasury/test/test-stablecoin.js

@@ -311,8 +311,8 @@ test('price drop', async t => {
   const loanParams = {
     chargingPeriod: 2n,
     recordingPeriod: 10n,
-    poolFee: 24,
-    protocolFee: 6,
+    poolFee: 24n,
+    protocolFee: 6n,
   };
   const manualTimer = buildManualTimer(console.log);
   const { creatorFacet: stablecoinMachine, publicFacet: lender } = await E(