1 files changed, 96 insertions, 0 deletions
diff --git a/packages/pipeline/src/scripts/pull_erc20_events.ts b/packages/pipeline/src/scripts/pull_erc20_events.ts
new file mode 100644
index 000000000..bd520c610
--- /dev/null
+++ b/packages/pipeline/src/scripts/pull_erc20_events.ts
@@ -0,0 +1,96 @@
+import { getContractAddressesForNetworkOrThrow } from '@0x/contract-addresses';
+import { web3Factory } from '@0x/dev-utils';
+import { Web3ProviderEngine } from '@0x/subproviders';
+import { logUtils } from '@0x/utils';
+import { Web3Wrapper } from '@0x/web3-wrapper';
+import 'reflect-metadata';
+import { Connection, ConnectionOptions, createConnection } from 'typeorm';
+
+import { ERC20EventsSource } from '../data_sources/contract-wrappers/erc20_events';
+import { ERC20ApprovalEvent } from '../entities';
+import * as ormConfig from '../ormconfig';
+import { parseERC20ApprovalEvents } from '../parsers/events';
+import { handleError, INFURA_ROOT_URL } from '../utils';
+
+const NETWORK_ID = 1;
+const START_BLOCK_OFFSET = 100; // Number of blocks before the last known block to consider when updating fill events.
+const BATCH_SAVE_SIZE = 1000; // Number of events to save at once.
+const BLOCK_FINALITY_THRESHOLD = 10; // When to consider blocks as final. Used to compute default endBlock.
+
+let connection: Connection;
+
+interface Token {
+    // name is used for logging only.
+    name: string;
+    address: string;
+    defaultStartBlock: number;
+}
+
+const tokensToGetApprovalEvents: Token[] = [
+    {
+        name: 'WETH',
+        address: getContractAddressesForNetworkOrThrow(NETWORK_ID).etherToken,
+        defaultStartBlock: 4719568, // Block when the WETH contract was deployed.
+    },
+    {
+        name: 'ZRX',
+        address: getContractAddressesForNetworkOrThrow(NETWORK_ID).zrxToken,
+        defaultStartBlock: 4145415, // Block when the ZRX contract was deployed.
+    },
+    {
+        name: 'DAI',
+        address: '0x89d24a6b4ccb1b6faa2625fe562bdd9a23260359',
+        defaultStartBlock: 4752008, // Block when the DAI contract was deployed.
+    },
+];
+
+(async () => {
+    connection = await createConnection(ormConfig as ConnectionOptions);
+    const provider = web3Factory.getRpcProvider({
+        rpcUrl: INFURA_ROOT_URL,
+    });
+    const endBlock = await calculateEndBlockAsync(provider);
+    for (const token of tokensToGetApprovalEvents) {
+        await getAndSaveApprovalEventsAsync(provider, token, endBlock);
+    }
+    process.exit(0);
+})().catch(handleError);
+
+async function getAndSaveApprovalEventsAsync(
+    provider: Web3ProviderEngine,
+    token: Token,
+    endBlock: number,
+): Promise<void> {
+    logUtils.log(`Getting approval events for ${token.name}...`);
+    logUtils.log('Checking existing approval events...');
+    const repository = connection.getRepository(ERC20ApprovalEvent);
+    const startBlock = (await getStartBlockAsync(token)) || token.defaultStartBlock;
+
+    logUtils.log(`Getting approval events starting at ${startBlock}...`);
+    const eventsSource = new ERC20EventsSource(provider, NETWORK_ID, token.address);
+    const eventLogs = await eventsSource.getApprovalEventsAsync(startBlock, endBlock);
+
+    logUtils.log(`Parsing ${eventLogs.length} approval events...`);
+    const events = parseERC20ApprovalEvents(eventLogs);
+    logUtils.log(`Retrieved and parsed ${events.length} total approval events.`);
+    await repository.save(events, { chunk: Math.ceil(events.length / BATCH_SAVE_SIZE) });
+}
+
+async function calculateEndBlockAsync(provider: Web3ProviderEngine): Promise<number> {
+    const web3Wrapper = new Web3Wrapper(provider);
+    const currentBlock = await web3Wrapper.getBlockNumberAsync();
+    return currentBlock - BLOCK_FINALITY_THRESHOLD;
+}
+
+async function getStartBlockAsync(token: Token): Promise<number | null> {
+    const queryResult = await connection.query(
+        `SELECT block_number FROM raw.erc20_approval_events WHERE token_address = $1 ORDER BY block_number DESC LIMIT 1`,
+        [token.address],
+    );
+    if (queryResult.length === 0) {
+        logUtils.log(`No existing approval events found for ${token.name}.`);
+        return null;
+    }
+    const lastKnownBlock = queryResult[0].block_number;
+    return lastKnownBlock - START_BLOCK_OFFSET;
+}