Merge pull request BitGo#5 from BitGo/BG-22216-Add-example-to-close-a…

…-CDP

Add example to close a CDP

examples/MakerDAO/closeCDP.ts

@@ -0,0 +1,72 @@
+import { BitGo } from 'bitgo';
+import * as ethUtil from 'ethereumjs-util';
+import { Contract } from '../../src/contract';
+
+const daiToken = new Contract('StandardERC20').instance('dai');
+
+async function sendBitGoTx(): Promise<void> {
+    // This assume you already have a CDP at Maker from our example createCDP
+    // It also assume you already have a CDP setup
+    // step 1 - Approve the number of tokens you would like the proxy to access
+
+    const bitGo = new BitGo({ env: 'prod' });
+    const baseCoin = bitGo.coin('eth');
+    const depositAmount = 5e18; // The amount of dai you want to deposit.
+    const withdrawAmount = 1e17; // The amount of eth you want to withdraw.
+    bitGo.authenticateWithAccessToken({ accessToken: 'access token' });
+    const bitGoWallet = await baseCoin.wallets().get({ id: 'wallet id' });
+    const walletPassphrase = 'password';
+
+    // your proxy
+    const proxyAddress = '0x17458bbdd96d6c19645457f5fae87ed5a07ad8fd';
+    const daiSavingsRateProxy = new Contract('DSProxy').address(proxyAddress);
+
+    let { data, amount, address } = daiToken.methods().approve.call(
+        {
+            _spender: proxyAddress,
+            _value: depositAmount.toString(10),
+        });
+    let transaction = await bitGoWallet.send({ data, amount, address, walletPassphrase });
+    console.dir(transaction);
+
+    // Note this step only needs to be done once based on the amount you approve
+
+    // ============================================ //
+    // ============================================ //
+
+    // step 2 - Deposit Dai and withdraw ETH
+
+    // Now we need to go get the cdp id of the cdp that you created. The easiest way to do this is go to
+    // the Etherscan page for the Dai manager contract, here: https://etherscan.io/address/0x5ef30b9986345249bc32d8928b7ee64de9435e39#readContract
+    // Enter your proxy address in the 'last' query, then press `Query`. It will return your cdpid
+    const cdp = '1913';
+
+    // The following two addresses are constants in the MakerDAO MCD ecosystem. You can look them up and verify on Etherscan
+    const daiJoin = '0x9759a6ac90977b93b58547b4a71c78317f391a28';
+    const ethJoin = '0x2f0b23f53734252bda2277357e97e1517d6b042a';
+    const manager = '0x5ef30b9986345249bc32d8928b7ee64de9435e39';
+
+    const dsProxyActionsContract = new Contract('DSProxyActions');
+
+    const { data: internalData, address: proxyActionsAddress } = dsProxyActionsContract.methods()
+        .wipeAndFreeETH.call({ manager, ethJoin, daiJoin, cdp, wadC: withdrawAmount.toString(10), wadD: depositAmount.toString(10) });
+
+    // Build the external call for our proxy to deposit dai and withdaw eth
+    ({ data, amount, address } = daiSavingsRateProxy.methods()
+        .execute.call({
+            _target: proxyActionsAddress,
+            _data: ethUtil.toBuffer(internalData),
+        }));
+    // send the transaction through BitGo
+
+    transaction = await bitGoWallet.send({
+        data,
+        address,
+        amount,
+        walletPassphrase,
+    });
+
+    console.dir(transaction);
+}
+
+sendBitGoTx();