Subscribe to new block event

src/client.ts

@@ -11,9 +11,29 @@
  *
  * Removal or modification of this copyright notice is prohibited.
  */
+import { resolve } from 'path';
 import { createIPCClient, APIClient } from '@liskhq/lisk-api-client';
+import { Block } from '@liskhq/lisk-chain';
+import { NEW_BLOCK_EVENT_NAME } from './constants';
+import { write } from './utils/fs';
 
 export const getAPIClient = async (liskCorePath: string): Promise<APIClient> => {
  const client = await createIPCClient(liskCorePath);
  return client;
 };
+
+export const subscribeToNewBlockEvent = (
+ client: APIClient,
+ snapshotHeight: number,
+ outputDir: string,
+) => {
+ client.subscribe(NEW_BLOCK_EVENT_NAME, async data => {
+ const { block: encodedBlock } = (data as unknown) as Record<string, string>;
+ const newBlock = client.block.decode(Buffer.from(encodedBlock, 'hex')) as Block;
+ if (newBlock.header.height === snapshotHeight) {
+ const forgingStatus = await client.invoke('app:getForgingStatus');
+ const forgingStatusJsonFilepath = resolve(outputDir, 'forgingStatus.json');
+ await write(forgingStatusJsonFilepath, JSON.stringify(forgingStatus));
+ }
+ });
+};

src/constants.ts

@@ -90,3 +90,4 @@ export const DEFAULT_LISK_CORE_PATH = '~/.lisk/lisk-core';
 export const LEGACY_DB_PATH = `${DEFAULT_LISK_CORE_PATH}/${DEFAULT_DATA_DIR}/legacy.db`;
 
 export const DEFAULT_VERSION = '0.1.0';
+export const NEW_BLOCK_EVENT_NAME = 'app:block:new';

src/index.ts

@@ -29,7 +29,7 @@ import {
  SNAPSHOT_TIME_GAP,
  LEGACY_DB_PATH,
 } from './constants';
-import { getAPIClient } from './client';
+import { getAPIClient, subscribeToNewBlockEvent } from './client';
 import {
  getConfig,
  migrateUserConfig,
@@ -140,6 +140,8 @@ class LiskMigrator extends Command {
  const networkConstant = NETWORK_CONSTANT[networkIdentifier] as NetworkConfigLocal;
  const outputDir = `${outputPath}/${networkIdentifier}`;
 
+ subscribeToNewBlockEvent(client, snapshotHeight, outputDir);
+
  if (autoStartLiskCoreV4) {
  if (!networkConstant) {
  this.error(

src/utils/fs.ts

@@ -67,3 +67,13 @@ export const copyDir = async (src: string, dest: string) => {
  : await fs.promises.copyFile(srcPath, destPath);
  }
 };
+
+export const write = async (filePath: string, content: string): Promise<boolean | Error> =>
+ new Promise((resolve, reject) => {
+ fs.writeFile(filePath, content, err => {
+ if (err) {
+ return reject(err);
+ }
+ return resolve(true);
+ });
+ });