bedrock

bedrock

A core foundation for rich Web applications.

Overview

When creating a Web app, you need a foundation on which to build. There are a lot of disparate technologies out there that can be brought together into a cohesive whole to make this happen. The trouble is in finding, vetting, testing, and combining these technologies -- all of which needs to happen before you can begin to make serious progress on your own project.

Bedrock helps you launch your ideas faster by bundling all the best-of-breed tooling that's necessary to build a modern, scalable Web app. It creates a solid foundation on which you can build, letting you focus on your project-specific needs.

Bedrock uses a modular design to help keep code well-organized and to allow an ecosystem to grow without unnecessary hindrance. Bedrock keeps its core simple: it provides a powerful configuration system, an event-based API, Linked Data-capabilities, and testing infrastructure that makes writing interactive modules easy. Bedrock is an opinionated, but flexible framework; it tells developers that there's one recommended way to accomplish a task, but if need be, a developer can go in another direction. Many of Bedrock's modules attempt to emulate this approach, creating organizing priniciples and clear guidelines for developers to follow that help break down problems and reduce cognitive load.

Bedrock uses node.js and runs on Linux, Mac OS X, and Windows. It can run on a low-powered laptop all the way up to an enterprise server.

Runnable Examples

A very basic, runnable "Hello World" bedrock example can be found at bedrock-hello-world.

More complex, runnable examples can be found at bedrock-examples.

Quick Examples

npm install bedrock

Create a MEAN stack application:

var bedrock = require('bedrock');

// modules
require('bedrock-express');
require('bedrock-docs');
require('bedrock-i18n');
require('bedrock-mongodb');
require('bedrock-protractor');
require('bedrock-request-limiter');
require('bedrock-requirejs');
require('bedrock-server');
require('bedrock-session-mongodb');
require('bedrock-validation');
require('bedrock-views');

bedrock.start();

To include the AngularJS-based frontend, bower install these modules:

bedrock-angular
bedrock-angular-alert
bedrock-angular-filters
bedrock-angular-form
bedrock-angular-lazy-compile
bedrock-angular-modal
bedrock-angular-model
bedrock-angular-selector
bedrock-angular-ui

Create a simple express-based bedrock application:

var bedrock = require('bedrock');

// modules
require('bedrock-express');

bedrock.events.on('bedrock-express.configure.routes', function(app) {
  app.get('/', function(req, res) {
    res.send('Hello World!');
  });
});

bedrock.start();

Create a bedrock REST application with an express server, mongodb database, and mongodb-backed session storage:

var bedrock = require('bedrock');

// modules
require('bedrock-express');
require('bedrock-mongodb');
require('bedrock-session-mongodb');

bedrock.events.on('bedrock-mongodb.ready', function(callback) {
  database.openCollections(['people'], function(err) {
    if(err) {
      return callback(err);
    }
    callback();
  });
});

bedrock.events.on('bedrock-express.configure.routes', function(app) {
  app.get('/people', function(req, res, next) {
    database.collections.people.find({}).toArray(function(err, docs) {
      if(err) {
        return next(err);
      }
      res.send(docs);
    });
  });

  app.get('/people/:name', function(req, res, next) {
    database.collections.people.findOne(
      {name: req.param('name')}, function(err, result) {
        if(err) {
          return next(err);
        }
        res.send(result);
      });
  });

  app.post('/people/:name', function(req, res){
    database.collections.people.insert(
      [{name: req.param('name')}], function(err, result) {
        if(err) {
          return next(err);
        }
        res.send(result.result);
      });
  });

  app.delete('/people/:name', function(req, res){
    database.collections.people.remove(
      {name: req.param('name')}, function(err, result) {
        if(err) {
          return next(err);
        }
        res.send(result.result);
      });
  });
});

bedrock.start();

To create a MEAN stack application with identity management and authentication, see the bedrock-seed project.

Comphrehensive Module Example

Below is an example that demonstrates Bedrock's event API. It creates a module with an http server that other modules can attach listeners to. It also registers a debug subcommand that displays the listeners that attached to the http server. The example also creates a module that attaches a simple "hello world" listener to the http server. The example demonstrates how to use Bedrock's event API to:

1. Register a subcommand and handle it if is detected when the command line is parsed.
2. Create a modular http server, listen to a privileged port (80), and emit a custom event to allow other modules to attach listeners to the server only after process privileges have been dropped.
3. Execute custom behavior (eg: print the server's registered event listeners) after all other modules have started, if a subcommand was detected.

Module bedrock-example-server.js:

var bedrock = require('bedrock');
var http = require('http');

// setup default module config
bedrock.config['example-server'] = {port: 80};

var server = http.createServer();

// emitted prior to command line parsing
bedrock.events.on('bedrock-cli.init', function() {
  // add a new subcommand executed via: node project.js debug
  var command = bedrock.program
    .command('debug')
    .description('display registered http listeners')
    .option(
      '--debug-event <event>',
      'The event to print listeners for. [request]')
    .action(function() {
      // save the parsed command information
      bedrock.config.cli.command = command;
    });
});

// emitted after the command line has been parsed
bedrock.events.on('bedrock-cli.ready', function() {
  var command = bedrock.config.cli.command;
  if(command.name() !== 'debug') {
    // `debug` not specified on the command line, return early
    return;
  }

  // emitted after all bedrock.start listeners have run
  bedrock.events.on('bedrock.ready', function() {
    // print out all the listeners that registered with the server
    var event = command.debugEvent || 'request';
    var listeners = server.listeners(event);
    console.log('listeners for event: ' + event);
    listeners.forEach(function(listener, index) {
      console.log(index, listener.toString());
    });
  });
});

// emitted before initialization, to allow any further configuration
bedrock.events.on('bedrock.configure', function() {
  if(bedrock.config.foo) {
    bedrock.config.foo.bar = true;
  }
});

// emitted for early initialization, prior to dropping process privileges
bedrock.events.on('bedrock.admin.init', function(callback) {
  // listen on port 80
  server.listen(bedrock.config['example-server'].port, function() {
    // ready, call callback to allow bedrock to continue processing events
    callback();
  });
});

// emitted for modules to do or schedule any unprivileged work on start up
bedrock.events.on('bedrock.start', function(callback) {
  // emit a custom event giving other modules access to the example server
  bedrock.events.emit('example.server.ready', server, function() {
    callback();
  });
});

// emitted after all bedrock.ready listeners have run
bedrock.events.on('bedrock.started', function() {
  console.log('everything is running now');
});

Module bedrock-example-listener.js:

var bedrock = require('bedrock');
require('./bedrock-example-listener');

// emitted to allow listeners to be attached to the example server
bedrock.events.on('example.server.ready', function(server) {
  server.on('request', function(request, response) {
    response.writeHead(200, {'Content-Type': 'text/plain'});
    response.end('Hello World\n');
  });
});

Example Main Project project.js:

var bedrock = require('bedrock');

// bedrock modules to load
require('./bedrock-example-server');
require('./bedrock-example-listener');

// change the port to use
// bedrock.config['example-server'].port = 8123;

bedrock.start();

Run the main project and display the debug information with:

node project.js debug --debug-event request

Example output:

2015-03-05T21:59:23.727Z - info: starting bedrock...
2015-03-05T21:59:23.729Z - info: running bedrock master process pid=7705
2015-03-05T21:59:23.904Z - info: running bedrock worker process workerPid=7711
2015-03-05T21:59:23.906Z - info: startup time: 6ms workerPid=7711
listeners for event: request
0 'function (request, response) {\n    response.writeHead(200, {\'Content-Type\': \'text/plain\'});\n    response.end(\'Hello World\\n\');\n  }'
everything is running now

Configuration

For documentation on Bedrock's core configuration, see config.js.

How It Works

Bedrock is a modular system built on node.js. Node.js modules typically communicate with each other using the CommonJS API (eg: require and module.exports, etc.), and Bedrock modules are no different. However, Bedrock also provides some additional low-level subsystems to help modules coordinate. These include: bedrock.config, bedrock.events, bedrock.jsonld, bedrock.loggers, bedrock.test, and bedrock.util.

To create a Bedrock project, all you need to do is create a JavaScript file, for example project.js, that requires bedrock, any other Bedrock modules you're interested in, and that then calls bedrock.start(). To run your project, run:

node project.js

If you're developing your project and you have installed all of the development packages for the Bedrock modules you're using, you can also easily test your project and any of the modules it has included by running:

node project.js test

This will execute Bedrock's built-in test framework, running all of the tests that each module has written. This approach ensures you're running tests for your entire project and its dependencies.

bedrock.config

Bedrock has a simple, but highly-customizable configuration system. All configuration variables are stored in a shared JavaScript object bedrock.config. The object is partitioned into separate configuration objects that are identified by the object's keys. For example Bedrock introduces the cli, core, constants, jsonld, and loggers object keys. The best practice for modules to claim their own area in the configuration object is to insert their default configuration object using a key that either matches their module name or that matches their module name minus any bedrock- prefix. For example, the bedrock-server module's specific configuration object can be found under bedrock.config.server. Modules may define whatever configuration variables they want to using whatever format is appropriate for their own use.

bedrock.events

It's sometimes necessary to allow modules to coordinate with each other in an orderly fashion. To achieve this, Bedrock provides an event API. Bedrock's event API is very similar to node's built-in EventEmitter, but it provides a few additional features.

In particular, when emitting an event, Bedrock can wait for a listener to run asynchronous code before executing the next listener. This allows each listener to run synchronously or asynchronously, depending on their individual needs, without worrying that the next listener or the next event will be emitted before they have completed what they need to do.

Bedrock's event system also provides another feature, which is the ability to cancel events. Event cancelation allows modules to build-in default behavior that can be canceled by other modules. Whenever a synchronous listener returns false or an asynchronous listener passes false to its callback, the event will not be emitted to the remaining listeners, and, if a callback was given when the event was emitted, it will be given the false value allowing the emitter to take a different action.

To a emit an event:

bedrock.events.emit('example-module.foo', data, function(err, result) {
  if(err) {
    console.log('an error occurred in a listener and the event was canceled');
    return;
  }
  if(result === false) {
    console.log('the event was canceled, but not due to an error');
    return;
  }
  console.log('the event was not canceled');
});

To create a synchronous listener:

bedrock.events.on('example-module.foo', function(data) {
  if(anErrorOccured) {
    throw new Error('foo');
  }
  if(shouldCancel) {
    return false;
  }
  // do something synchronous
});

To create an asynchronous listener:

bedrock.events.on('example-module.foo', function(data, callback) {
  // because an additional parameter was added to the listener function,
  // it is assumed it should be a function and a callback will be passed
  // that *must* be called
  if(anErrorOccurred) {
    return callback(new Error('foo'));
  }
  if(shouldCancel) {
    return callback(null, false);
  }
  // do something asynchronous, other listeners won't execute and event
  // emission won't continue until you call the callback
  process.nextTick(function() {
    callback();
  });
});

Note that the asynchronous analog for throwing an error is calling the callback with an error as its first parameter and the analog for returning a value (typically only used for event cancelation) is to pass null for the first parameter and the return value for the second parameter of the callback. This API matches the "error-first" callback continuation-style that is standard practice in node.

Bedrock core emits several events that modules may listen for. These events fall into two possible namespaces: bedrock-cli and bedrock. The bedrock-cli events are emitted to allow coordination with Bedrock's command line interface. The bedrock events are emitted after the bedrock-cli events, unless a listener cancels the bedrock-cli.ready event or causes the application to exit early.

• bedrock-cli.init
  • Emitted before command line parsing. Allows registration of new subcommands.
• bedrock-cli.ready
  • Emitted after command line parsing. Allows execution of subcommands or the prevention of bedrock events from being emitted, either by canceling this event or by exiting the application early.
• bedrock-cli.test.configure
  • Emitted during bedrock-cli.init after test subcommand has been registered. Listeners receive the test command object. Allows modules that define new test frameworks to add new test command line options via the test command object.
• bedrock.test.configure
  • Emitted during bedrock-cli.ready, before bedrock.configure. Allows listeners to make configuration changes for running tests.
• bedrock.configure
  • Emitted after bedrock-cli.ready and before bedrock.admin.init. Allows additional custom configuration before Bedrock initializes but after command line parsing.
• bedrock.admin.init
  • Emitted after bedrock.configure and before elevated process privileges are dropped. Allows listeners to perform early initialization tasks that require special privileges. Note that, if Bedrock is started with elevated privileges (ie: as root), listeners will execute with those privileges. Any early initialization that needs to execute before bedrock.start but does not require elevated privileges should be deferred to bedrock.init. Most modules should find binding to bedrock.init to be sufficient for any initialization work.
• bedrock.init
  • Emitted after bedrock.admin.init and just after elevated process privileges are dropped. Allows listeners to perform early initialization tasks that do not require special privileges. This event should be used to ensure, for example, that a module's API has the required supporting data structures in memory prior to another module's use of it. For example, a validation module may need to load validation schemas from files on disk before they can be accessed via its API, but this loading must occur after the configuration events have passed and after special process privileges have been dropped. As a best practice, modules should not emit custom events during bedrock.init because it may cause scenarios where two unrelated modules can't be easily combined. For example, if a module emits a custom event during bedrock.init, then a listener of that event would be unable to use the API of an unrelated module that hasn't been initialized yet. Deferring custom event emitting to bedrock.start solves this problem; it ensures all modules have had a chance to complete initialization before attempting to interact with one another through the event system.
• bedrock.start
  • Emitted after bedrock.init. This is the event modules should use to execute or schedule their main background behavior and to emit any custom events they would like to make available to their dependents.
• bedrock.ready
  • Emitted after bedrock.start. Allows listeners to execute custom behavior after all modules have handled the bedrock.start event. This event is useful for turning on external access to web services or other modular systems that should now be fully ready for use. It can also be used to run analysis on modules that have started, for example, to build live documentation.
• bedrock.started
  • Emitted after bedrock.ready. External access to web services or other features provided by modules should now be available. Allows custom subcommands or behavior to run after Bedrock has fully started, eg: tests.
• bedrock.tests.run
  • Emitted during bedrock.started. Once Bedrock has fully started, this event is emitted to inform test frameworks to run their tests. Listeners are passed a test state object with a pass property that they can set to false to indicate to the test subsystem that at least one test did not pass. Test frameworks may add their own information to the state object using a property matching their framework name.

bedrock.jsonld

Bedrock is intended to provide a foundation for Linked Data applications, and as such, it provides a JSON-LD processor (via jsonld.js) that is integrated with its configuration system. Any JSON-LD context that is inserted into the bedrock.config.constants.CONTEXTS object (where keys are the URL for the context and the values are the context itself), will be served from disk instead of retrieved from the Web. This is a useful feature for both developing Linked Data applications and for ensuring contexts are available in offline mode.

bedrock.loggers

Bedrock has a built-in logging subsystem based on winston. Anything you can do with winston, you can do with Bedrock. Bedrock provides a set of default loggers that are suitable for most applications. The main application logger can be retrieved via bedrock.loggers.get('app').

bedrock.test

Bedrock comes with test support built-in. It provides a test framework based on mocha that integrates with bedrock.config. To add a mocha test to a Bedrock module, you simply push a directory or a file path onto the config.mocha.tests array. Bedrock also makes it easy to add other test frameworks via Bedrock modules. For example, bedrock-protractor integrates the AngularJS protractor test framework with Bedrock. Whenever you run tests against your project, your project and all of its dependencies will be tested, using whatever test frameworks they have registered with. Bedrock also provides command line options to limit the tests that run as desired.

bedrock.util

Bedrock provides a number of helpful general purpose utilities. For example, Bedrock defines a BedrockError class that extends the default Error class. A BedrockError can keep track of a series of "causes" (other errors) that allow developers to better understand why an error occured. BedrockErrors can also be marked as public, which allows modules that may, for example, serve error information over the Web to display more error details. bedrock.util also contains tools for formatting dates, extending/merging/cloning objects, and generating UUIDs.

Recommended Modules

bedrock-server provides a core, cluster-based HTTPS server.

bedrock-express provides an Express server with reasonable defaults and extra features like the ability to layer static files and directories to support overrides.

bedrock-mongodb provides an API for connecting to a MongoDB database and creating and using collections.

bedrock-jobs provides a background job scheduler.

bedrock-requirejs provides a client-side module loader and autoconfiguration capabilities for bower components.

bedrock-views provides server-rendered views with HTML5 + Bootstrap3.

bedrock-angular layers on top of bedrock-views to provide client-rendered AngularJS views.

bedrock-idp provides user identity and public key management.

bedrock-protractor integrates protractor with Bedrock, exposing a powerful end-to-end AngularJS test framework to Bedrock modules.

Other Bedrock modules provide REST APIs, user account management, strong cryptography support, DoS protection, digital signatures, Linked Data, and tons of other FEATURES. If you don't need all the fancy features, Bedrock is modular, so you can use only the modules you want.

Quickstart

You can follow the following tutorial to setup and use Bedrock on a Linux or Mac OS X development machine.

Requirements

• Linux, Mac OS X, Windows
• node.js >= 0.10.x
• npm >= 1.4.x

Running Bedrock

Run the following to start up a development server from the source directory:

node index.js

To add more verbose debugging, use the --log-level option:

node index.js --log-level debug

Running the Tests

Run all tests:

npm test

Run only the mocha test framework:

node index.js test --framework mocha

Run a specific mocha test:

node index.js test --framework mocha --mocha-test tests/test.js

Running the Code Coverage Tool

npm run coverage

Look at 'coverage.html' using a web browser

Features

For an example list of features provided by Bedrock modules, see the FEATURES file.

FAQ

See the FAQ file for answers to frequently asked questions.

Hacking

See the CONTRIBUTING file for various details for coders about hacking on this project.

Authors

See the AUTHORS file for author contact information.

License

Bedrock and all Bedrock modules are:

Copyright (c) 2011-2015 Digital Bazaar, Inc.
All Rights Reserved

You can use Bedrock for non-commercial purposes such as self-study, research, personal projects, or for evaluation purposes. See the LICENSE file for details about the included non-commercial license information.

Changelog

1.0.3 - 2015-07-16

Fixed

• Bug that caused workers to not be restarted.