kube-service-bindings

kube-service-bindings

Service bindings is kubernetes spec on how to communicate service secrets to applications in an automated way. The spec is available here.

The goal of this package is to make it easy for Node.js applications to consume these secrets, without requiring developers to be familiar with service bindings.

The package provides the getBinding method which does roughly the following:

• Looks for the $SERVICE_BINDING_ROOT variable in order to determine if bindings are available.
• Reads the info from the files.
• Maps the names of the files to the options names needed by the Node.js clients that will connect to the service.

The parameters for getBinding include:

• type - The type of service for which a binding is being requested. Currently the supported types are:

  • 'KAFKA'
  • 'POSTGRESQL'
  • 'REDIS'
  • 'MONGODB'

• client - the package the application is using to connect to the service. kube-service-bindings is aware of a subset of possible packages. For those that it is aware of, it can map the service bindings into the form required by the client. Currently the following clients are recognized based on the supported types:

  • KAFKA
    • node-rdkafka
    • kafkajs
  • POSTGRESQL
    • pg
  • REDIS
    • redis
    • ioredis
  • MONGODB
    • mongodb

  If you don't specify a client, the object returned will be a direct map from the bindings, with the keys corresponding to the name of each file provided by the binding.

• id - option id that is used to filter the available bindings in the search. Most useful for testing where you might have more than one binding of a given type available.

This is an example of how kube-service-bindings might be used:

const Kafka = require('node-rdkafka');
const serviceBindings = require('kube-service-bindings');

try {
  // check if the deployment has been bound to a kafka instance through
  // service bindings. If so use that connect info
  kafkaConnectionBindings = serviceBindings.getBinding('KAFKA', 'node-rdkafka');
} catch (err) { // proper error handling here
};

const stream = Kafka.KafkaConsumer.createReadStream(
  Object.assign({
    'group.id': 'consumer-test', // identifier to use to help trace activity in Kafka
    'socket.keepalive.enable': true, // Enable TCP keep-alives on broker sockets
    'enable.auto.commit': false // Automatically and periodically commit offsets in the background.
  }, kafkaConnectionBindings),
  {},
  {
    topics: 'countries'
  }
);