Migrate Elasticsearch stored scripts

README.md

Migrate Elasticsearch stored scripts

This is a standalone migration script to export and imports Elasticsearch Stored Scripts.

Usage

Export scripts from your ES cluster:

node migrate.js export http://localhost:9200

This will create a es-stored-scripts.json file containing the scripts.

Then you can import them:

node migrate.js import http://localhost:9200

migrate.js

const fs = require('fs');

// Embedded "min-req-promise" package
const http = require('http');
const https = require('https');
const URL = require('url');

const client = (url) => /^https/.test(url) ? https : http;

const httpRequest = (url, method, options = {}) => new Promise((resolve, reject) => {
  const u = URL.parse(url);

  const req = client(url).request(Object.assign({}, options, {
    method,
    hostname: u.hostname,
    port: u.port,
    path: u.path,
  }), res => {
    let buffer = new Buffer.alloc(0);

    res.on('data', chunk => {
      buffer = Buffer.concat([buffer, chunk]);
    });
    res.on('end',() => {
      if (options.responseEncoding
        || !res.headers['content-type']
        || /^(text|application\/json)/.test(res.headers['content-type'])
      ) {
        let charset = 'utf-8';

        if (options.responseEncoding) {
          charset = options.responseEncoding;
        }
        else if (res.headers['content-type']) {
          const match = /;\s*charset=(.*)/.exec(res.headers['content-type']);
          if (match) {
            charset = match[1];
          }
        }

        charset = charset.toLowerCase()
          .replace(/^iso-?8859(-1)?$/, 'latin1');

        if ([
            'ascii',
            'base64',
            'binary',
            'hex',
            'ucs2',
            'ucs-2',
            'utf16le',
            'utf-16le',
            'utf8',
            'utf-8',
            'latin1'
          ].indexOf(charset) < 0) {
          // unsupported charset, fallback to utf-8
          charset = 'utf-8';
        }

        res.body = buffer.toString(charset);
      }
      else {
        // assume binary content
        res.body = buffer;
      }

      resolve(res);
    });

    res.on('error', reject);

    res.on('timeout', () => reject(req));
  });

  req.on('error', reject);
  req.write(options.body || '');
  req.end();
});
const httpGet = (url, options = {}) => httpRequest(url, 'GET', options);
const httpPut = (url, options = {}) => httpRequest(url, 'PUT', options);
// End "min-req-promise" package

const action = process.argv[2];
const target = process.argv[3];

async function exportScripts (target) {
  console.log(`Export scripts from ${target} to "es-stored-scripts.json"`);

  const response = await httpGet(`${target}/_cluster/state/metadata?pretty&filter_path=**.stored_scripts`);

  const scripts = JSON.parse(response.body).metadata.stored_scripts;

  fs.writeFileSync('es-stored-scripts.json', JSON.stringify(scripts, null, 2));
}

async function importScripts (target) {
  console.log(`Import scripts from "es-stored-scripts.json" to ${target}`);

  const scripts = JSON.parse(fs.readFileSync('es-stored-scripts.json'));

  for (const [name, script] of Object.entries(scripts)) {
    await httpPut(`${target}/_scripts/${name}`, {
      headers: {
        'Content-Type': 'application/json',
      },
      body: JSON.stringify({ script })
    });
  }
}

if (action === 'export') {
  exportScripts(target);
}
else {
  importScripts(target);
}