binder-module

Base class for a PM2-managed, Express-based Binder module

An instance of BinderModule implements a subset of the API defined in binder-protocol, with HTTP handlers defined for each implemented endpoint.

A BinderModule is initialized with a list of components it will implement (currently chosen from build, registry, and deploy). Once the desired API subset has been declared, the _makeBinderAPI method is responsible for binding instance methods (HTTP handlers) to their appropriate API endpoints.

_makeOtherRoutes lets you define other HTTP handlers external to the Binder API that will also be registered on the Express app at launch time.

install

binder-module is designed to make the lifecycles of independent Binder servers simpler to manage, but it has limited use outside of that context.

If you're modifying or extending the Binder API, and you'd like to make another module, from within that module's directory:

npm install binder-module --save

Then extend your existing module with

inherits(YourBinderModule, BinderModule)

usage

The correct behavior for every Binder API endpoint is described in the Binder protocol file. Handlers are registered in _makeBinderAPI as a list of mappings from handler name to instance method:

BinderBuild.prototype._makeBinderAPI = function () {
  return {
    statusAll: this._getAllBuilds.bind(this),
    status: this._getBuild.bind(this),
    start: this._startBuild.bind(this),
    fetch: this._fetchTemplate.bind(this),
    fetchAll: this._fetchAllTemplates.bind(this)
  }
}

Each handler is passed a reference to an API object, when provides success/error handlers matching the success/error conditions defined in the protocol file:

BinderBuild.prototype._getBuild = function (api) {
  var self = this
  if (!this.buildInfo) {
    return api._noBuildInfo()
  }
  console.log('api.params: {0}'.format(JSON.stringify(api.params)))
  this.buildInfo.findOne({ name: api.params['image-name'] }, function (err, info) {
    if (err) {
      return api._badQuery({ error: err })
    }
    if (!info || (info === {})) {
      return api._noBuildInfo()
    }
    return api._success({
      'name': info.name,
      'start-time': info.startTime,
      'status': info.status,
      'phase': info.phase,
      'repository': info.repo,
      'error': info.error
    })
  })
}

In this example from binder-build, the input/output properties of the noBuildInfo and badQuery error conditions are defined in the protocol file, as is the return value for the success condition. Additionally, the value of api.params is type-checked prior to the _getBuild method being invoked, and error handling for bad parameters are all handled in a single place.

examples

Currently, the binder-build and binder-deploy-kubernetes modules implement instances of BinderModule in their lib/server.js files.