gremlin-migrate

Runs gremlin-groovy scripts in-order to upgrade the DB schema

This library can be used to run a sequence of groovy scripts, which are submitted to gremlin-javascript, to perform changes on the target database. Most likely these will be schema changes.

The files are ordered based on semver naming conventions.

Installation

npm install gremlin-migrate --save

Usage

The library exports a function taking configuration parameters and returning an ES6 promise.

import upgradeDbToLatest from 'gremlin-migrate';
...
upgradeDbToLatest(janusGraphDbAddress, portNumber, pathToUpgradeScriptDirectory).then(() => {
    console.log('SUCCESS!');
});

Script library

If you want to use common functions across your groovy files, you can put them in a 'common.groovy' file in the update script directory. These will be available in all of the upgrade files.

Example

0.0.1.groovy (in 'upgradeScripts' subdir)

// I am an example of a comment!
graph.addVertex(label, 'person').property('name', 'john').iterate();
person2 = graph.addVertex(label, 'person');
// NOTE: Don't forget to add the '.next()' else the step won't necessarily take effect!
person2.property('name', 'john').next();
// DON'T put transactions in your upgrade scripts. The scripts are automatically wrapped in a transaction.
// graph.tx().commit();

Example.ts

import { createClient } from 'gremlin';
import upgradeDbToLatest from 'gremlin-migrate';
const client = createClient(8182, '192.168.99.100');

export default class Example {
  public test() {
    client.execute('g.V().hasLabel(\'person\').has(\'name\', \'john\')', (err, results) => {
      console.log('BEFORE UPGRADE: ' + JSON.stringify(results)); // []
      upgradeDbToLatest('192.168.99.100', 8182, __dirname + '/upgradeScripts/').then(() => {
        client.execute('g.V().hasLabel(\'person\').has(\'name\', \'john\')', (err, results) => {
          console.log('AFTER UPGRADE: ' + JSON.stringify(results)); // [ {vertex with person 'john'} ]
        });
      });
    });
  }
}

Tests

The tests are run against a janus-graph/dynamoDb backend configuration to exercise the transaction locking. They spin up docker containers using docker-compose with an empty DB so you will need docker set up on your system.

Run 'docker-compose build' and wait until that finishes (this is a one-off step)

Run 'gulp build' to build the app.

Then run 'gulp test' to run the tests.

To Publish

1. Build and test the app.
2. Run 'gulp export' to prepare for the release
3. Commit and push your changes up to github
4. npm publish!

About

My specific use-case was for flyway-like migrations for janus-graph, but I couldn't find a tool that did that.

Contributions

Pull requests will be gratefully received. Please ensure you have a test around the change/improvement you are proposing.