Adapter for Chainlink oracles.

artifacts/index.ts

@@ -1,3 +1,4 @@
+export { ChainlinkOracleAdapter } from './ts/ChainlinkOracleAdapter';
 export { ConstantPriceOracle } from './ts/ConstantPriceOracle';
 export { CTokenOracle } from './ts/CTokenOracle';
 export { DydxOracleAdapter } from './ts/DydxOracleAdapter';
@@ -24,6 +25,7 @@ export { UpdatableOracleMock } from './ts/UpdatableOracleMock';
 // Export abi-gen contract wrappers
 export {
 	BaseContract,
+	ChainlinkOracleAdapterContract,
 	ConstantPriceOracleContract,
 	CTokenOracleContract,
 	DydxOracleAdapterContract,

contracts/meta-oracles/proxies/ChainlinkOracleAdapter.sol

@@ -0,0 +1,70 @@
+/*
+    Copyright 2020 Set Labs Inc.
+
+    Licensed under the Apache License, Version 2.0 (the "License");
+    you may not use this file except in compliance with the License.
+    You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+    Unless required by applicable law or agreed to in writing, software
+    distributed under the License is distributed on an "AS IS" BASIS,
+    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+    See the License for the specific language governing permissions and
+    limitations under the License.
+*/
+
+pragma solidity 0.5.7;
+
+import { SafeMath } from "openzeppelin-solidity/contracts/math/SafeMath.sol";
+import { AggregatorInterface } from "chainlink/v0.5/contracts/dev/AggregatorInterface.sol";
+
+
+/**
+ * @title ChainlinkOracleAdapter
+ * @author Set Protocol
+ *
+ * Coerces outputs from Chainlink oracles to uint256 and adapts value to 18 decimals.
+ */
+contract ChainlinkOracleAdapter {
+    using SafeMath for uint256;
+
+    /* ============ Constants ============ */
+    uint256 public constant PRICE_MULTIPLIER = 1e10;
+
+    /* ============ State Variables ============ */
+    AggregatorInterface public oracle;
+
+    /* ============ Constructor ============ */
+    /*
+     * Set address of aggregator being adapted for use
+     *
+     * @param  _oracle    The address of medianizer being adapted from bytes to uint256
+     */
+    constructor(
+        AggregatorInterface _oracle
+    )
+        public
+    {
+        oracle = _oracle;
+    }
+
+    /* ============ External ============ */
+
+    /*
+     * Reads value of oracle and coerces return to uint256 then applies price multiplier
+     *
+     * @returns         Chainlink oracle price in uint256
+     */
+    function read()
+        external
+        view
+        returns (uint256)
+    {
+        // Read value of medianizer and coerce to uint256
+        uint256 oracleOutput = uint256(oracle.latestAnswer());
+
+        // Apply multiplier to create 18 decimal price (since Chainlink returns 8 decimals)
+        return oracleOutput.mul(PRICE_MULTIPLIER);
+    }
+}

contracts/mocks/ChainlinkAggregatorMock.sol

@@ -0,0 +1,15 @@
+pragma solidity 0.5.7;
+
+contract ChainlinkAggregatorMock {
+  int256 public latestAnswer;
+  uint256 public latestTimestamp;
+
+  constructor(int256 _latestAnswer) public {
+    setLatestAnswer(_latestAnswer);
+  }
+
+  function setLatestAnswer(int256 _latestAnswer) public {
+    latestAnswer = _latestAnswer;
+    latestTimestamp = now;
+  }
+}

package.json

@@ -1,6 +1,6 @@
 {
   "name": "set-protocol-oracles",
-  "version": "1.0.1",
+  "version": "1.0.2",
   "main": "dist/artifacts/index.js",
   "typings": "dist/typings/artifacts/index.d.ts",
   "files": [
@@ -91,6 +91,7 @@
   "dependencies": {
     "bn-chai": "^1.0.1",
     "canonical-weth": "^1.3.1",
+    "chainlink": "^0.7.10",
     "dotenv": "^6.2.0",
     "eth-gas-reporter": "^0.1.10",
     "ethlint": "^1.2.3",

test/contracts/oracles/proxies/chainlinkOracleAdapter.spec.ts

@@ -0,0 +1,96 @@
+require('module-alias/register');
+
+import * as _ from 'lodash';
+import * as chai from 'chai';
+
+import { Address } from 'set-protocol-utils';
+import { BigNumber } from 'bignumber.js';
+import { ether } from '@utils/units';
+
+import ChaiSetup from '@utils/chaiSetup';
+import { BigNumberSetup } from '@utils/bigNumberSetup';
+import { Blockchain } from '@utils/blockchain';
+
+import {
+  ChainlinkAggregatorMockContract,
+  ChainlinkOracleAdapterContract,
+} from '@utils/contracts';
+
+import { getWeb3 } from '@utils/web3Helper';
+
+import { OracleHelper } from '@utils/helpers/oracleHelper';
+
+BigNumberSetup.configure();
+ChaiSetup.configure();
+const web3 = getWeb3();
+const { expect } = chai;
+const blockchain = new Blockchain(web3);
+
+contract('chainlinkOracleAdapter', accounts => {
+  const [
+    deployerAccount,
+  ] = accounts;
+
+  let customDollarValue: number;
+  let customOracleValue: BigNumber;
+  let chainlinkAggregatorMock: ChainlinkAggregatorMockContract;
+
+  let chainlinkOracleAdapter: ChainlinkOracleAdapterContract;
+
+
+  const oracleHelper = new OracleHelper(deployerAccount);
+
+  beforeEach(async () => {
+    blockchain.saveSnapshotAsync();
+
+    customDollarValue = 100;
+    // Equal to 100 since Chainlink numbers are 8 decimal
+    customOracleValue = new BigNumber(10 ** 8).mul(customDollarValue);
+    chainlinkAggregatorMock = await oracleHelper.deployChainlinkAggregatorMockAsync(
+      customOracleValue
+    );
+  });
+
+  afterEach(async () => {
+    blockchain.revertAsync();
+  });
+
+  describe('#constructor', async () => {
+    let subjectChainlinkOracleAddress: Address;
+
+    beforeEach(async () => {
+      subjectChainlinkOracleAddress = chainlinkAggregatorMock.address;
+    });
+
+    async function subject(): Promise<ChainlinkOracleAdapterContract> {
+      return oracleHelper.deployChainlinkOracleAdapterAsync(
+        subjectChainlinkOracleAddress,
+      );
+    }
+
+    it('sets the correct Chainlink Oracle Address', async () => {
+      chainlinkOracleAdapter = await subject();
+
+      const actualChainlinkOracleAddress = await chainlinkOracleAdapter.oracle.callAsync();
+
+      expect(actualChainlinkOracleAddress).to.be.bignumber.equal(subjectChainlinkOracleAddress);
+    });
+  });
+
+  describe('#read', async () => {
+    beforeEach(async () => {
+      chainlinkOracleAdapter = await oracleHelper.deployChainlinkOracleAdapterAsync(
+        chainlinkAggregatorMock.address,
+      );
+    });
+
+    async function subject(): Promise<BigNumber> {
+      return chainlinkOracleAdapter.read.callAsync();
+    }
+
+    it('returns the correct price in uint256', async () => {
+      const actualTokenPrice = await subject();
+      expect(actualTokenPrice).to.be.bignumber.equal(ether(customDollarValue));
+    });
+  });
+});

utils/contracts.ts

@@ -1,9 +1,11 @@
 export { BaseContract } from '../types/base_contract';
+export { ChainlinkAggregatorMockContract } from '../types/generated/chainlink_aggregator_mock';
+export { ChainlinkOracleAdapterContract } from '../types/generated/chainlink_oracle_adapter';
+export { ConstantPriceOracleContract } from '../types/generated/constant_price_oracle';
+export { CTokenOracleContract } from '../types/generated/c_token_oracle';
 export {
   DataSourceLinearInterpolationLibraryMockContract
 } from '../types/generated/data_source_linear_interpolation_library_mock';
-export { ConstantPriceOracleContract } from '../types/generated/constant_price_oracle';
-export { CTokenOracleContract } from '../types/generated/c_token_oracle';
 export { DydxConstantPriceOracleMockContract } from '../types/generated/dydx_constant_price_oracle_mock';
 export { DydxOracleAdapterContract } from '../types/generated/dydx_oracle_adapter';
 export { EMALibraryMockContract } from '../types/generated/e_m_a_library_mock';

utils/helpers/oracleHelper.ts

@@ -8,6 +8,8 @@ import { Blockchain } from '@utils/blockchain';
 import { ether } from '@utils/units';
 
 import {
+  ChainlinkAggregatorMockContract,
+  ChainlinkOracleAdapterContract,
   ConstantPriceOracleContract,
   CTokenOracleContract,
   DydxConstantPriceOracleMockContract,
@@ -41,6 +43,8 @@ import { FeedCreatedArgs } from '../contract_logs/oracle';
 
 const web3 = getWeb3();
 
+const ChainlinkAggregatorMock = artifacts.require('ChainlinkAggregatorMock');
+const ChainlinkOracleAdapter = artifacts.require('ChainlinkOracleAdapter');
 const ConstantPriceOracle = artifacts.require('ConstantPriceOracle');
 const CTokenOracle = artifacts.require('CTokenOracle');
 const DydxConstantPriceOracleMock = artifacts.require('DydxConstantPriceOracleMock');
@@ -481,6 +485,36 @@ export class OracleHelper {
     );
   }
 
+  public async deployChainlinkOracleAdapterAsync(
+    oracle: Address,
+    from: Address = this._contractOwnerAddress
+  ): Promise<ChainlinkOracleAdapterContract> {
+    const oracleAdapter = await ChainlinkOracleAdapter.new(
+      oracle,
+      txnFrom(from),
+    );
+
+    return new ChainlinkOracleAdapterContract(
+      getContractInstance(oracleAdapter),
+      txnFrom(from),
+    );
+  }
+
+  public async deployChainlinkAggregatorMockAsync(
+    oracleValue: BigNumber,
+    from: Address = this._contractOwnerAddress
+  ): Promise<ChainlinkAggregatorMockContract> {
+    const oracleAMock = await ChainlinkAggregatorMock.new(
+      oracleValue,
+      txnFrom(from),
+    );
+
+    return new ChainlinkAggregatorMockContract(
+      getContractInstance(oracleAMock),
+      txnFrom(from),
+    );
+  }
+
   /* ============ Transactions ============ */
 
   public async addPriceFeedOwnerToMedianizer(