index.js

const axios = require('axios');

// Epoch to data to send to the finalize endpoint
const knownCheckpoints = {
  "117136": {
    "epoch": "117136",
    "state_root": "0x6d92a3a81ce8b90ad71c11d7bcd80c551866c0dcf334f843e0234df216d90770",
    "block_root": "0xe48389dee2da56c7101f0dacc4c5020ec91eb425ff40d16e3b924271eef53edd",
  },
  "117729": {
    "epoch": "117729",
    "state_root": "0x1505b771a01bd5991b0ad3d412f26aaefe1bc03ee40369467d5ced9d85c6e243",
    "block_root": "0x5b1a381ca774dd62ba3a7061d356c2e66d6c19a405d082236ef87c6b522f8111",
  }
};

const hosts = process.env.LIGHTHOUSE_HOSTS.split(";").map(host => {
  if (!host.startsWith('http')) {
    host = `http://${host}`;
  }
  return host;
})
const SLOTS_PER_EPOCH = 32;

async function singleHostLogic(host) {
  try {
    // Ask the beacon about its known head
    const lastCheckpoint = await axios.get(`${host}/eth/v1/beacon/headers/head`)
      .then(r => r.data.data)
      .then(r => r.header.message.slot)
      .then(r => Math.floor(r / SLOTS_PER_EPOCH) - 3);
    console.log(`${host} is at epoch ${lastCheckpoint}`)

    let lastCheckpointData, tryCheckpoint = lastCheckpoint;
    while (!lastCheckpointData) {
      lastCheckpointData = knownCheckpoints[tryCheckpoint];
      if (lastCheckpointData) {
        break;
      }
      lastCheckpointData = await axios.get(`${host}/eth/v1/beacon/headers/${tryCheckpoint * SLOTS_PER_EPOCH}`)
        .then(r => r.data.data)
        .then(r => r.header.message.slot && r) // Ensure the data is present
        .then(r => knownCheckpoints[tryCheckpoint] = {
          epoch: tryCheckpoint,
          block_root: r.root,
          state_root: r.header.message.state_root,
        })
        .catch(e => {
          console.warn(`Could not fetch data for epoch ${tryCheckpoint} from ${host}, trying older: ${e}`);
        });

      // Some epochs don't have a valid checkpoint. In that case try the epoch before
      tryCheckpoint--;

      if (lastCheckpoint > tryCheckpoint + 10) {
        throw new Error("Could not find a working checkpoint in the last 10 epochs. Can't force finalize for now");
      }
    }
    console.log(`Asking Lighthouse to finalize with data ${JSON.stringify(lastCheckpointData)}`);

    // Now, send a finalize request
    await axios.post(`${host}/lighthouse/finalize`, lastCheckpointData)
      .then(r => r.data)
      .then(r => console.log(`${host} finalization request result: ${JSON.stringify(r)}`))

    await axios.post(`${host}/lighthouse/compaction`)
    .then(r => r.data)
    .then(r => console.log(`${host} compaction request result: ${JSON.stringify(r)}`));
  } catch (e) {
    console.error(`Host error for ${host}`, e);
  }
}

async function lightHouseLoop() {
  console.log("Loop start");

  await Promise.all(hosts.map(singleHostLogic));

  console.log("Loop end");
}

const loopInterval = setInterval(lightHouseLoop, 600e3);
lightHouseLoop();

process.on('SIGINT', () => {
  clearInterval(loopInterval);
});

k8s.yaml

apiVersion: apps/v1
kind: StatefulSet
metadata:
  name: tmp-lighthouse-sync-helper
spec:
  selector:
    matchLabels:
      app: tmp-lighthouse-sync-helper
  serviceName: tmp-lighthouse-sync-helper
  replicas: 1
  template:
    metadata:
      labels:
        app: tmp-lighthouse-sync-helper
        author: kiln-fi
        details: lighthouse_holesky_sync_helper
    spec:
      nodeSelector:
        k8s.scaleway.com/role: metal
      containers:
      - name: tmp-lighthouse-sync-helper
        image: node:23
        command:
        - /bin/bash
        - -c
        - npm i --no-package-lock && node index.js
        workingDir: /app
        env:
        - name: LIGHTHOUSE_HOSTS
          value: holesky-lighthouse-beacon-rbx-1-0.holesky-lighthouse-beacon-rbx-1:5052;holesky-lighthouse-beacon-rbx-4-0.holesky-lighthouse-beacon-rbx-4:5052;holesky-lighthouse-beacon-rbx-5-0.holesky-lighthouse-beacon-rbx-5:5052;holesky-lighthouse-beacon-sbg-1-0.holesky-lighthouse-beacon-sbg-1:5052
        resources:
          limits:
            cpu: 500m
            memory: 128Mi
          requests:
            cpu: 250m
            memory: 128Mi
        volumeMounts:
        - name: app
          mountPath: /app
        - name: node-modules
          mountPath: /app/node_modules
      volumes:
      - name: app
        configMap:
          name: tmp-lighthouse-sync-helper
  volumeClaimTemplates:
  - metadata:
      name: node-modules
    spec:
      # storageClassName: k8s-storage
      accessModes: [ "ReadWriteOnce" ]
      resources:
        requests:
          storage: 1Gi
---
apiVersion: v1
kind: ConfigMap
metadata:
  name: tmp-lighthouse-sync-helper
data:
  package.json: |
    {
     "name": "tmp-lighthouse-sync-helper",
      "version": "1.0.0",
      "description": "A script forcing Lighthouse to prune its storage, useful to handle holesky pectra forks.",
      "main": "index.js",
      "scripts": {
        "test": "echo \"Error: no test specified\" && exit 1"
      },
      "author": "Kiln.fi",
      "license": "ISC",
      "dependencies": {
        "axios": "^1.8.2"
      }
    }
  index.js: |
    const axios = require('axios');

    // Epoch to data to send to the finalize endpoint
    const knownCheckpoints = {
      "117136": {
        "epoch": "117136",
        "state_root": "0x6d92a3a81ce8b90ad71c11d7bcd80c551866c0dcf334f843e0234df216d90770",
        "block_root": "0xe48389dee2da56c7101f0dacc4c5020ec91eb425ff40d16e3b924271eef53edd",
      },
      "117729": {
        "epoch": "117729",
        "state_root": "0x1505b771a01bd5991b0ad3d412f26aaefe1bc03ee40369467d5ced9d85c6e243",
        "block_root": "0x5b1a381ca774dd62ba3a7061d356c2e66d6c19a405d082236ef87c6b522f8111",
      }
    };

    const hosts = process.env.LIGHTHOUSE_HOSTS.split(";").map(host => {
      if (!host.startsWith('http')) {
        host = `http://${host}`;
      }
      return host;
    })
    const SLOTS_PER_EPOCH = 32;

    async function singleHostLogic(host) {
      try {
        // Ask the beacon about its known head
        const lastCheckpoint = await axios.get(`${host}/eth/v1/beacon/headers/head`)
          .then(r => r.data.data)
          .then(r => r.header.message.slot)
          .then(r => Math.floor(r / SLOTS_PER_EPOCH) - 3);
        console.log(`${host} is at epoch ${lastCheckpoint + 3} - working with epoch ${lastCheckpoint}`)

        let lastCheckpointData, tryCheckpoint = lastCheckpoint;
        while (!lastCheckpointData) {
          lastCheckpointData = knownCheckpoints[tryCheckpoint];
          if (lastCheckpointData) {
            break;
          }
          lastCheckpointData = await axios.get(`${host}/eth/v1/beacon/headers/${tryCheckpoint * SLOTS_PER_EPOCH}`)
            .then(r => r.data.data)
            .then(r => r.header.message.slot && r) // Ensure the data is present
            .then(r => knownCheckpoints[tryCheckpoint] = {
              epoch: tryCheckpoint,
              block_root: r.root,
              state_root: r.header.message.state_root,
            })
            .catch(e => {
              console.warn(`Could not fetch data for epoch ${tryCheckpoint} from ${host}, trying older: ${e}`);
            });

          // Some epochs don't have a valid checkpoint. In that case try the epoch before
          tryCheckpoint--;

          if (lastCheckpoint > tryCheckpoint + 10) {
            throw new Error("Could not find a working checkpoint in the last 10 epochs. Can't force finalize for now");
          }
        }
        console.log(`Asking Lighthouse to finalize with data ${JSON.stringify(lastCheckpointData)}`);

        // Now, send a finalize request
        await axios.post(`${host}/lighthouse/finalize`, lastCheckpointData)
          .then(r => r.data)
          .then(r => console.log(`${host} finalization request result: ${JSON.stringify(r)}`))

        await axios.post(`${host}/lighthouse/compaction`)
        .then(r => r.data)
        .then(r => console.log(`${host} compaction request result: ${JSON.stringify(r)}`));
      } catch (e) {
        console.error(`Host error for ${host}`, e);
      }
    }

    async function lightHouseLoop() {
      console.log("Loop start");

      await Promise.all(hosts.map(singleHostLogic));

      console.log("Loop end");
    }

    const loopInterval = setInterval(lightHouseLoop, 600e3);
    lightHouseLoop();

    process.on('SIGINT', () => {
      clearInterval(loopInterval);
    });

package.json

{
  "name": "tmp-lighthouse-sync-helper",
  "version": "1.0.0",
  "description": "A script forcing Lighthouse to prune its storage, useful to handle holesky pectra forks.",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "Kiln.fi",
  "license": "ISC",
  "dependencies": {
    "axios": "^1.8.2"
  }
}