hydros

Hydros

Hydros creates and regularly updates a SQL table given a datasource and a transform function. Typically this is used to keep an analytics SQL database up-to-date from production databases.

For example, you might need to JOIN across user accounts in MongoDB and usage counters in Redis. Hydros makes it easy to keep a SQL table synced with each of those production databases, and then run the JOIN query without hitting production resources.

A hydros implementation of an "Active Users" table might work like this:

• list user IDs from Mongo
• get each user's activity by pulling counters from Redis

A hydros table pulls data from a source via the list and get methods, which you implement. The list method generates a complete list of ids. Then get generates all the rows associated with each id.

Usage

Hydros is an abstract module. It handles table creation and syncing. You just need to specify the name, columns, list and get functions:

var Hydros = require('Hydros');

var APIUsage = Hydros('API Usage')
  .column('Today', 'INTEGER')
  .column('Past Month', 'INTEGER')
  .list(function (callback) {
    // Get a complete list of Project IDs, pass the array
    // to the callback.
    // callback(err, [...array of ids...]);
  })
  .get(function (id, callback) {
    // Get the API Usage data for this Project, pass it
    // to the callback as a dictionary.
    // callback(err, {...dictionary of columns...});
    // OR
    // callback(err, [...array of rows, each a dict of columns...]);
  });

new APIUsage(connection)
  .refresh(2 * 3600 * 1000) // every two hours
  .on('error', function (err) {
    console.log(err);
  })
  .start();

License

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(The MIT License)

Copyright (c) 2013 Segment.io Inc. [e-mail]

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the 'Software'), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.