Add keepers example using function selector checkData

contracts/KeepersCounter.sol

@@ -8,27 +8,83 @@ contract Counter is KeeperCompatibleInterface {
     */
     uint public counter;
 
+    /**
+    * Public multiplier boolean variable
+    */
+    bool public multiplierEnabled;
+
     /**
     * Use an interval in seconds and a timestamp to slow execution of Upkeep
     */
     uint public immutable interval;
     uint public lastTimeStamp;
+
+	// keccak256 hash of empty checkData
+	bytes32 constant public emptyCheckDataHash = 0xc5d2460186f7233c927e7db2dcc703c0e500b653ca82273b7bfad8045d85a470;
 
-    constructor(uint updateInterval) {
+    constructor(uint updateInterval, bool _multiplierEnabled) {
       interval = updateInterval;
       lastTimeStamp = block.timestamp;
-
       counter = 0;
+      multiplierEnabled = _multiplierEnabled;
+    }
+
+	function setMultiplierEnabled(bool _enabled) external {
+		multiplierEnabled = _enabled;
+	}
+
+    function checkMultiplier() external view returns (bool upkeepNeeded, bytes memory performData) {
+        upkeepNeeded = multiplierEnabled && (counter == 3 || counter == 10);
+        if (upkeepNeeded) {
+            uint256 multiplier = counter % 2 == 0 ? 10 : 3;
+            performData = abi.encodeWithSelector(this.multiplyCounter.selector, multiplier);
+        }
+        return (upkeepNeeded, performData);
     }
 
-    function checkUpkeep(bytes calldata /* checkData */) external override returns (bool upkeepNeeded, bytes memory /* performData */) {
-        upkeepNeeded = (block.timestamp - lastTimeStamp) > interval;
-        // We don't use the checkData in this example. The checkData is defined when the Upkeep was registered.
+    function checkReset() external view returns (bool upkeepNeeded, bytes memory performData) {
+        upkeepNeeded = counter > 100;
+        performData = abi.encodePacked(bytes4(abi.encodeWithSelector(this.resetCounter.selector, "")));
+        return (upkeepNeeded, performData);
+    }
+
+    function multiplyCounter(uint256 _amount) external {
+        require(multiplierEnabled && (counter == 3 || counter == 10), "Upkeep not satisfied");
+        require(counter == _amount, "Only valid multiplier");
+        counter *= _amount;
+    }
+
+    function resetCounter() external {
+        require(counter > 100, "Too early");
+        counter = 0;
+    }
+
+    function checkUpkeep(bytes calldata checkData)
+		external
+		view
+		override
+		returns (bool upkeepNeeded, bytes memory performData)
+	{
+		if (keccak256(checkData) == emptyCheckDataHash) {
+			// We don't use the checkData in this example. The checkData is defined when the Upkeep was registered.
+			upkeepNeeded = (block.timestamp - lastTimeStamp) > interval;
+			performData = "";
+		} else {
+            (bool success, bytes memory returnedData) = address(this).staticcall(checkData);
+            require(success);
+
+            (upkeepNeeded, performData) = abi.decode(returnedData, (bool, bytes));
+        }
     }
 
-    function performUpkeep(bytes calldata /* performData */) external override {
-        lastTimeStamp = block.timestamp;
-        counter = counter + 1;
-        // We don't use the performData in this example. The performData is generated by the Keeper's call to your checkUpkeep function
+    function performUpkeep(bytes calldata performData) external override {
+		lastTimeStamp = block.timestamp;
+        if (keccak256(performData) == emptyCheckDataHash) {
+			// We don't use the performData in this example. The performData is generated by the Keeper's call to your checkUpkeep function
+			counter = counter + 1;
+		} else {
+            (bool success, ) = address(this).call(performData);
+            require(success);
+        }
     }
 }

deploy/04_Deploy_KeepersCounter.js

@@ -10,11 +10,12 @@ module.exports = async ({
     const { deployer } = await getNamedAccounts()
     const chainId = await getChainId()
     let keepersUpdateInterval = networkConfig[chainId]['keepersUpdateInterval']
+    let multiplierEnabled = networkConfig[chainId]['multiplierEnabled']
     // Price Feed Address, values can be obtained at https://docs.chain.link/docs/reference-contracts
     // Default one below is ETH/USD contract on Kovan
     const keepersCounter = await deploy('Counter', {
         from: deployer,
-        args: [keepersUpdateInterval],
+        args: [keepersUpdateInterval, multiplierEnabled],
         log: true
     })
     log("Head to https://keepers.chain.link/ to register your contract for upkeeps. Then run the following command to track the counter updates")

helper-hardhat-config.js

@@ -5,15 +5,17 @@ const networkConfig = {
         keyHash: '0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4',
         jobId: '29fa9aa13bf1468788b7cc4a500a45b8',
         fundAmount: "1000000000000000000",
-        keepersUpdateInterval: "30"
+        keepersUpdateInterval: "30",
+        multiplierEnabled: "true"
     },
     31337: {
         name: 'localhost',
         fee: '100000000000000000',
         keyHash: '0x6c3699283bda56ad74f6b855546325b68d482e983852a7a82979cc4807b641f4',
         jobId: '29fa9aa13bf1468788b7cc4a500a45b8',
         fundAmount: "1000000000000000000",
-        keepersUpdateInterval: "30"
+        keepersUpdateInterval: "30",
+        multiplierEnabled: "true"
     },
     42: {
         name: 'kovan',
@@ -25,7 +27,8 @@ const networkConfig = {
         jobId: 'd5270d1c311941d0b08bead21fea7747',
         fee: '100000000000000000',
         fundAmount: "1000000000000000000",
-        keepersUpdateInterval: "30"
+        keepersUpdateInterval: "30",
+        multiplierEnabled: "true"
     },
     4: {
         name: 'rinkeby',
@@ -37,13 +40,15 @@ const networkConfig = {
         jobId: '6b88e0402e5d415eb946e528b8e0c7ba',
         fee: '100000000000000000',
         fundAmount: "1000000000000000000",
-        keepersUpdateInterval: "30"
+        keepersUpdateInterval: "30",
+        multiplierEnabled: "true"
     },
     1: {
         name: 'mainnet',
         linkToken: '0x514910771af9ca656af840dff83e8264ecf986ca',
         fundAmount: "0",
-        keepersUpdateInterval: "30"
+        keepersUpdateInterval: "30",
+        multiplierEnabled: "true"
     },
     5: {
         name: 'goerli',

package.json

@@ -14,6 +14,7 @@
     "@nomiclabs/hardhat-etherscan": "^2.1.7",
     "@nomiclabs/hardhat-waffle": "^2.0.1",
     "@nomiclabs/hardhat-web3": "^2.0.0",
+    "@openzeppelin/test-helpers": "^0.5.15",
     "chai": "^4.3.4",
     "chai-bignumber": "^3.0.0",
     "chai-bn": "^0.2.1",

test/unit/KeepersCounter_unit_test.js

@@ -5,6 +5,7 @@ const skipIf = require('mocha-skip-if')
 chai.use(require('chai-bn')(BN))
 const { deployments, getChainId } = require('hardhat')
 const { networkConfig, developmentChains } = require('../../helper-hardhat-config')
+const { expectRevert } = require('@openzeppelin/test-helpers')
 
 skip.if(!developmentChains.includes(network.name)).
   describe('Keepers Counter Unit Tests', async function () {
@@ -14,19 +15,118 @@ skip.if(!developmentChains.includes(network.name)).
       await deployments.fixture(['mocks', 'keepers'])
       const Counter = await deployments.get("Counter")
       counter = await ethers.getContractAt("Counter", Counter.address)
+      chainId = await getChainId()
     })
 
-    it('should be able to call checkUpkeep', async () => {
-      const checkData = ethers.utils.keccak256(ethers.utils.toUtf8Bytes(""));
-      const { upkeepNeeded, performData } = await counter.checkUpkeep(checkData);
-    })
+    context("Basic upkeep", async () => {
+      it('should be able to call checkUpkeep', async () => {
+        const checkData = ethers.utils.hexlify("0x");
+        const { upkeepNeeded, performData } = await counter.checkUpkeep(checkData);
+      })
 
-    it('should be able to call performUpkeep', async () => {
-        const checkData = ethers.utils.keccak256(ethers.utils.toUtf8Bytes(""));
+      it('should be able to call performUpkeep', async () => {
+        const checkData = ethers.utils.hexlify("0x");
         await counter.performUpkeep(checkData);
         //now get the new counter value
         const result = await counter.counter()
         console.log("Keepers Counter value: ", new ethers.BigNumber.from(result._hex).toString())
         expect(new ethers.BigNumber.from(result).toString()).to.be.a.bignumber.that.is.greaterThan(new ethers.BigNumber.from(0).toString())
       })
+    })
+
+    context("Upkeep with checkData - unhappy paths", async () => {
+      before(function() {
+        if(networkConfig[chainId].multiplierEnabled == "false") this.skip();
+      });
+      it("Should not require upkeep from checkMultiplier if not enabled", async () => {
+        await counter.setMultiplierEnabled(false);
+        const returnData = await counter.checkMultiplier()
+        expect(returnData[0]).to.be.equal(false)
+      })
+
+      it("Should not multiply counter if not enabled", async () => {
+        await expectRevert(counter.multiplyCounter(3), "Upkeep not satisfied")
+      })
+
+      it("Should not require upkeep from checkMultiplier if not valid value", async () => {
+        await counter.setMultiplierEnabled(true);
+        const returnData = await counter.checkMultiplier()
+        expect(returnData[0]).to.be.equal(false)
+      })
+
+      it("Should not multiply counter if not valid value", async () => {
+        for(let i=0; i<3; i++) {
+          await counter.performUpkeep(ethers.utils.hexlify("0x"));
+        }
+        await expectRevert(counter.multiplyCounter(2), "Only valid multiplier")
+      })
+
+      it("Should not require upkeep from checkReset if too early", async () => {
+        const returnData = await counter.checkReset()
+        expect(returnData[0]).to.be.equal(false)
+      })
+
+      it("Should not reset counter if too early", async () => {
+        await expectRevert(counter.resetCounter(), "Too early")
+      })
+    })
+
+    context("Upkeep with checkData - happy paths", async () => {
+      before(function() {
+        if(networkConfig[chainId].multiplierEnabled == "false") this.skip();
+      });
+      beforeEach(async () => {
+        for(let i=0; i<3; i++) {
+          await counter.performUpkeep(ethers.utils.hexlify("0x"));
+        }
+      })
+
+      it("Should be able to call checkUpkeep for checkMultiplier", async () => {
+        const abi = ["function checkMultiplier()", "function multiplyCounter(uint)"]
+        const iface = new ethers.utils.Interface(abi)
+        const checkData = iface.encodeFunctionData("checkMultiplier", [])
+        console.log(`checkMultiplier checkData: ${checkData}`)
+        const { upkeepNeeded, performData } = await counter.checkUpkeep(checkData)
+        const calldata = iface.encodeFunctionData("multiplyCounter", ["3"])
+        expect(upkeepNeeded).to.be.equal(true)
+        expect(performData).to.be.equal(calldata)
+      })
+
+      it("Should call performUpkeep for multiplyCounter", async () => {
+        const abi = ["function multiplyCounter(uint)"]
+        const iface = new ethers.utils.Interface(abi)
+        const checkData = iface.encodeFunctionData("multiplyCounter", ["3"])
+        await counter.performUpkeep(checkData)
+        const result = await counter.counter()
+        expect(result).to.be.equal(new ethers.BigNumber.from("9"))
+      })
+
+      it("Should be able to call checkUpkeep for checkReset", async () => {
+        await counter.multiplyCounter(3);
+        await counter.performUpkeep(ethers.utils.hexlify("0x"));
+        await counter.multiplyCounter(10);
+        await counter.performUpkeep(ethers.utils.hexlify("0x"));
+        const abi = ["function checkReset()", "function resetCounter()"]
+        const iface = new ethers.utils.Interface(abi)
+        const checkData = iface.encodeFunctionData("checkReset", [])
+        console.log(`checkReset checkData: ${checkData}`)
+        const { upkeepNeeded, performData } = await counter.checkUpkeep(checkData)
+        const calldata = iface.encodeFunctionData("resetCounter", [])
+        expect(upkeepNeeded).to.be.equal(true)
+        expect(performData).to.be.equal(calldata)
+      })
+
+      it("Should call performUpkeep for resetCounter", async () => {
+        await counter.multiplyCounter(3);
+        await counter.performUpkeep(ethers.utils.hexlify("0x"));
+        await counter.multiplyCounter(10);
+        await counter.performUpkeep(ethers.utils.hexlify("0x"));
+        const abi = ["function resetCounter()"]
+        const iface = new ethers.utils.Interface(abi)
+        const checkData = iface.encodeFunctionData("resetCounter", [])
+        await counter.performUpkeep(checkData)
+        const result = await counter.counter()
+        expect(result).to.be.equal(new ethers.BigNumber.from("0"))
+      })
+    })
   })