volos-quota-apigee

volos-quota-apigee

This is an implementation of API quotas for the Volos family of modules. It uses Apigee as a backing store to keep quotas synchronized across many nodes. Furthermore, this is the correct module to use if deploying the Node.js application to Apigee, because it will result in quotas that work in the same way as the quotas that are built in to the Apigee platform.

Once initialized, the interface to the module is exactly what is in the "volos-quota-common" module. See that module for detailed docs.

Installing the Adapter

This module depends on an "adapter," which is a special API that is deployed to Apigee for your specific organization in the Apigee cloud. This proxy is hosted in the Volos GitHub repo, which is here:

https://github.com/apigee/volos

The proxy is inside the "proxy" directory. Instructions for deploying it may be found here:

https://github.com/apigee/volos/blob/master/samples/basic/README.md

Initialization

To initialize a quota, you call "create" on the exported module and pass a single "options" object. It can contain the following parameters:

• timeUnit: How often the quota resets -- may be in minutes, hours, days, or weeks
• interval: Works with the timeUnit to determine how often the quota resets. For instance, every 5 days or 2 weeks.
• startTime: A time at which the quota calculations should begin. For instance, if there is no start time then a quota set to reset in "one day" will reset 24 hours after the first message is receiver, but if the start time is set to the top of the hour on some day, then the quota will always reset at the top of the hour.
• allow: The maximum number of requests to allow. This may be overridden on each "apply" call if desired.
• uri: The full URI of the Apigee adapter that you deployed in the last step. For instance, if the organization name is "foo" then this might be "https://foo-test.apigee.net/adapterproxy".
• key: An API consumer key for a valid "application" that is part of the same organization where the adapter was installed.
• bufferSize: (Number) optional, create a local memory buffer to hold up to bufferSize for quota elements
• bufferTimeout: (Number) optional, flush the memory buffer (if exists) every Number ms (default: 300)

Once the quota has been initialized, the module that is returned has the programming interface defined by the "volos-quota-common" module.

Example

var quotaModule = require('volos-quota-apigee');
var quota = quotaModule.create({
  timeUnit: 'day',
  interval: 1,
  allow: 10,
  uri: process.env.APIGEEURI,
  key: process.env.APIGEEKEY
  });

quota.apply({ identifier: 'Foo', weight: 1 }, function(err, result) {
  if (err) {
    throw err;
  } else {
    console.log('Quota status: %s', result.isAllowed);
  }
});