Registry

• Introduction
• Setup
• API
• Registry configuration
• Registry events
• Plugins

Introduction

The registry is a REST api that serves the components. You can have multiple registries connected to a library, but you can't have multiple libraries connected to a registry.

Setup

First, create a dir and install oc:

mkdir oc-registry && cd oc-registry
npm init
npm install oc --save
touch index.js

For Google Storage registry configuration's documentation, look at this page.

This is the index.js content:

var oc = require('oc');

var configuration = {
  verbosity: 0,
  baseUrl: 'https://my-components-registry.mydomain.com/',
  port: 3000,
  tempDir: './temp/',
  refreshInterval: 600,
  pollingInterval: 5,
  s3: {
    key: 'your-s3-key',
    secret: 'your-s3-secret',
    bucket: 'your-s3-bucket',
    region: 'your-s3-region',
    path: '//s3.amazonaws.com/your-s3-bucket/',
    componentsDir: 'components'
  },
  env: { name: 'production' }
};

var registry = new oc.Registry(configuration);

registry.start(function(err, app){
  if(err){
    console.log('Registry not started: ', err);
    process.exit(1);
  }
});

API

var registry = new oc.Registry(configuration);

Creates an instance of the registry. Configuration is an object that contains the registry configuration parameters.

registry.start(callback)

Starts the registry.

registry.off(eventName, callback);

For unsubscribing to an event.

registry.on(eventName, callback);

For subscribing to an event.

registry.register(plugin [, callback]);

Register a plugin. The plugin parameter has to be a valid plugin.

registry.register({
  name: 'doSomething',
  register: require('my-oc-plugin'),
  options: {
    configuration: 'value'
  }
});

registry.reset(eventName);

For unsuscribing to all events.

Registry configuration

Parameter	Type	Mandatory	Description
baseUrl	string	yes	sets the URL which will be used to compose the components' URLs. This needs to be the registry's public url
customHeadersToSkipOnWeakVersion	array	no	the custom headers to skip when serving a component requested by a weak version (eg. 1.x.x rather than 1.2.3). This is useful, for instance, in case of components that have quite static logic, setting cache headers - so that it makes sense in order to implement reactive consumers' caches
dependencies	array	no	the npm modules available for components logic
discovery	boolean	no	Enable registry UI. Default: true
env	object	no	sets the registry environment
env.name	string	no	sets the environment name
executionTimeout	number (seconds)	no	timeout for component's server execution time
fallbackRegistryUrl	string (url)	no	Url to another registry which will be used by current registry when component cannot be found in current registry
keepAliveTimeout	number (milliseconds)	no	Keep Alive Timeout for HTTP server. Default: 5000
pollingInterval	number (seconds)	no	When the components' list cache will be refreshed. This is required for distributing the components on each registry instance. Given the polling mechanism is quite efficient, this number should be very low. Suggested is around 5-10 seconds.
port	number	no	default 3000, sets the port where to start the registry
postRequestPayloadSize	string	no	Sets the limit for the post body size. Example: 50mb. When unset, the limit is 100KB
prefix	string	no	sets the href prefix, for example: /v2/
publishAuth	object	no	sets the authentication parameters for publishing a component to the registry. When undefined, no authorisation is required.
publishAuth.type	string	no	The authorisation type. Only basic is supported at the moment.
publishAuth.username	string	no	sets the user name
publishAuth.password	string	no	sets the user password
publishValidation	function	no	Used to validate package.json when components is published. Look at the example
refreshInterval	number (seconds)	no	When the components' data cache will be refreshed. Given the data is immutable, this should be high and just for robustness.
routes	array of objects	no	sets additional actions via URL mapping to specific action handlers
routes[index].route	string	no	sets URL pattern. Routes should be outside of the components' namespace (which you can set by using the prefix parameter.)
routes[index].method	string	no	sets verb
routes[index].handler	function	no	sets function handler for routed action Look at the example
s3	object	yes	sets the Amazon S3 credentials
s3.agentProxy	instance of http agent	no	allows to interact with aws API via a custom agent and a proxy. Usage: agentProxy = require('proxy-agent')('https://yourproxy.com');
s3.bucket	string	yes	sets S3 bucket
s3.componentsDir	string	yes	the path where the data will be saved inside the bucket
s3.key	string	no	sets S3 access key. User should either specify both key/secret or skip both when leveraging IAM Role based S3 access from EC2
s3.path	string	yes	sets the path that will be used for composing static resources' urls. Can be the s3 url, or, when using cloudfront, it can be //cloudfront-id.cloudfront.net/. Signature should not include the protocol
s3.region	string	yes	sets S3 region
s3.secret	string	no	sets S3 secret. User should either specify both key/secret or skip both when leveraging IAM Role based S3 access from EC2
s3.timeout	number (milliseconds)	no	default 10000, optionally sets the timeout for s3 requests.
tempDir	string	no	default ./temp/, sets the directory where the components' packages are temporarily stored during the publishing phase inside the registry box
templates	array	no	the templates available allowed on the registry. Will extend the default base templates of [require('oc-template-jade'), require('oc-template-handlebars')]
timeout	number (milliseconds)	no	Socket timeout for HTTP server. Default: 0
verbosity	number	no	default 0, sets the console.log verbosity during the execution

Publish validation example

options.publishValidation = function(package){
  var isValid = !!package.author &&
                !!package.repository &&
                !!package.description;

  if(isValid){
    // Can return boolean
    return true;
  } else {
    // Can return object with error so that it will be propagated to the user
    return {
      isValid: false,
      error: 'Package.json is missing mandatory params: author, repository, description'
    };
  }
};

Routes example

options.routes = [{
  route: '/example-route',
  method: 'get',
  handler: function(req, res){
    // Handling function content
  }
}];

Registry events

Event name	Callback Data Type	Description
cache-poll	object	Fired when the components list is refreshed. The callback data contains the last edit unix utc timestamp.
component-retrieved	object	Fired when the component is retrieved. This includes the component's validation, data gathering and execution, view retrieving, and (when requested) rendering. The callback data contains the duration, component details, and, in case, the error details.
error	object	Fired when an internal operation errors.
request	object	Fired every time the registry receives a request. The callback data contains some request and response details.
start	undefined	Fired when the registry starts

Plugins

Plugins are a way to extend registry's context allowing components to inherit custom functionalities.

This is a plugin example:

// ./registry/oc-plugins/hobknob.js
var connection,
    client = require('./hobknob-client');

module.exports.register = function(options, dependencies, next){
  client.connect(options.connectionString, function(err, conn){
    connection = conn;
    next();
  });
};

module.exports.execute = function(featureName){
  return connection.get(featureName);
};

This is how to register it in a registry:

// ./registry/init.js
...
var registry = new oc.Registry(configuration);

registry.register({
  name: 'getFeatureSwitch',
  register: require('./oc-plugins/hobknob'),
  options: {
      connectionString: connectionString
  }
});
...

This is how to use a plugin from a component:

// ./my-component/server.js
module.exports.data = function(context, callback){
  callback(null, {
    variable: context.plugins.getFeatureSwitch('AbTestHomePage')
  });
};

This is how to depend on (and use) other plugins:

// ./registry/oc-plugins/hobknob.js
var connection,
    client = require('./hobknob-client');

module.exports.dependencies = ['log', 'otherplugin'];

module.exports.register = function(options, dependencies, next){
  // this register function is only called after all dependencies are registered
  client.connect(options.connectionString, function(err, conn){
    connection = conn;
    dependencies.log('hobknob client initialised');
    next();
  });
};

module.exports.execute = function(featureName){
  return connection.get(featureName);
};