parity auto-kill script

.gitignore

/node_modules
*.log

README.md

auto kill parity to work around parity issue #11737

auto kills / restarts a parity node when it is out of date by more than 7 mins (which should never happen normally) or down

if node does not exit gracefully, sigkill it

start parity either using an auto-restarting manager like systemd or using

while true; do parity --foo --params; sleep 1m; done

When node is synced, run the kill script using this:

npm install
parity_url=http://localhost:8545 npm run auto-kill-parity | tee -a log$(date -I).log

auto-kill-parity.ts

/**
 * shitty script to kill parity because it keeps getting stuck after a few hours to a few days
 */

import { JsonRpcProvider } from "ethers/providers";
import { exec as _exec } from "child_process";
import { promisify } from "util";

const exec = promisify(_exec);

function sleep(time_ms: number): Promise<void> {
	return new Promise(resolve => setTimeout(resolve, time_ms));
}

async function getBlockAgeMinutes(localBackend: JsonRpcProvider) {
	const blkHeight = await localBackend.getBlockNumber();
	const blk = await localBackend.getBlock(blkHeight);
	const blockAge = new Date().getTime() - blk.timestamp * 1000;
	const blockAgeMinutes = blockAge / 1000 / 60;
	return blockAgeMinutes;
}
function log(...args: any[]) {
	console.log(new Date(), ...args);
}

async function go() {
	const url = process.env.parity_url;
	if (!url) {
		throw Error("supply backend in env parity_url");
	}
	const localBackend = new JsonRpcProvider(url);

	while (true) {
		const blockAgeMinutes = await Promise.race([
			getBlockAgeMinutes(localBackend),
			sleep(60 * 1000).then(() => Promise.reject("timeout")),
		]).catch(e => {
			log("error", e);
			return "down" as const;
		});

		if (blockAgeMinutes === "down" || blockAgeMinutes > 7) {
			log(`block is ${blockAgeMinutes} min old, killing node`);
			try {
				// safeguard: if process has been running for less than an hour, maybe it's still syncing up?
				await exec("killall parity --older-than 60m");
			} catch (e) {
				log("pkill 1 fail", e);
			}
			await sleep(60 * 1000);
			// if it takes more than 60s to exit, sigkill
			try {
				await exec("killall parity --older-than 60m --signal KILL");
			} catch (e) {
				log("pkill 2 fail", e);
			}
			await sleep(600 * 1000);
		} else {
			log(`parity is current (${blockAgeMinutes.toFixed(1)} min)`);
		}

		await sleep(20 * 1000);
	}
}

go();

package.json

{
  "scripts": {
    "auto-kill-parity": "ts-node --transpile-only auto-kill-parity.ts"
  },
  "dependencies": {
    "ethers": "^4.0.47",
    "ts-node": "^8.9.0",
    "typescript": "^3.8.3",
    "web3": "^1.2.7"
  }
}

@phiresky awesome work. i would recommend run this script on something like pm2, for keep it alive all the time.