A bedrock module that creates a simple MongoDB database and provides an easy API for creating and working with its collections.
- npm v3+
npm install bedrock-mongodb
Below is an example that simply opens a collection when the database is ready
and then runs a query and prints the result. A more common use case for a
module that uses bedrock-mongodb would be to expose its own API that hides
the details of using whatever collections it has opened.
var bedrock = require('bedrock');
var database = require('bedrock-mongodb');
// custom configuration
bedrock.config.mongodb.name = 'my_project_dev'; // default: bedrock_dev
bedrock.config.mongodb.host = 'localhost'; // default: localhost
bedrock.config.mongodb.port = 27017; // default: 27017
bedrock.config.mongodb.username = 'my_project'; // default: bedrock
bedrock.config.mongodb.password = 'password'; // default: password
// the mongodb database 'my_project_dev' and the 'my_project' user will
// be created on start up following a prompt for the admin user credentials
// alternatively, use `mongodb` URL format:
bedrock.config.mongodb.url = 'mongodb://localhost:27017/my_project_dev';
// enable local collection if a local database is available
// the local database has similar options to primary database
// see lib/config.js for details
// bedrock.config.mongodb.local.enable = true; // default: false
// open some collections once the database is ready
bedrock.events.on('bedrock-mongodb.ready', function(callback) {
database.openCollections(['collection1', 'collection2'], function(err) {
if(err) {
return callback(err);
}
// do something with the open collection(s)
database.collections.collection1.find({id: 'foo'}, function(err, result) {
if(err) {
return callback(err);
}
console.log('result', result);
callback();
});
});
});
bedrock.start();Below is an example demonstrating the use of a distributed ID generator.
var database = require('bedrock-mongodb');
database.getDistributedIdGenerator('mynamespace', function(err, idGenerator) {
if(err) {
console.error('Error', err);
return;
}
idGenerator.generateId(function(err, id) {
if(err) {
console.error('Error', err);
return;
}
console.log('ID generated', identifier);
});
});For documentation on database configuration, see config.js.
- Linux or Mac OS X (also works on Windows with some coaxing)
- node.js >= 4.x.x
- npm >= 1.4.x
- mongodb ~= 3.x
- libkrb5-dev >= 1.x.x
- Ensure an admin user is set up on mongodb. To do so, follow the instructions at mongodb.org for your version of MongoDB. Version 3.x is currently supported.
- [optional] Tweak your project's configuration settings; see Configuration or Quick Examples.
An object whose keys are the names of the collections that have been
opened via openCollections.
Opens a set of collections (creating them if necessary), if they aren't already
open. Once all of the collections are open, callback is called. If an error
occurs, callback is called immediately with the error. If no error occurs,
then once the callback has been called, collections object will have keys
that match the collection names and values that are instances of
mongodb-native
Collection.
Gets the DistributedIdGenerator for the given namespace. If the
DistributedIdGenerator does not exist, it will be created. The callback
will be passed an error if one occurred, otherwise it will be passed null
for the error and the DistributedIdGenerator instance. A
DistributedIdGenerator can be used to quickly generate unique identifiers
in a safe and distributed manner.
The underlying assumption that prevents identifier collisions is that there is a shared collection (amongst all machines) with synchronized write access. To ensure identifiers can be generated without waiting for a system-wide lock, this collection is only hit once a local identifier namespace is exhausted, which should be very rare.
A distributed ID looks like:
<version>.<globalId>.<localId>.<currentId>
Where '.' is the reserved separator character. The globalId is stored
in a shared database and can only be updated atomically.
The version is hardcoded to 1. The localId can be any combination of
alphanumeric characters not including .. The . character was chosen
instead of - or _ because those characters are used in URL-safe base64
encodings. This allows globalId and localId parts to be encoded in base64,
however, they are encoded in hex in the current implementation as is the
currentId.
Generates a new unique, URL-safe identifier. The identifier is guaranteed
not to conflict with any other identifier generated using the same namespace,
regardless of the machine used to generate it (provided that the machines
share the same database). If an error occurs, the callback will be called
with the error, otherwise, it will be called with null for the error and
the identifier.
When doing testing, it is often desirable to have empty collections at the beginning of test operations. This may be accomplished by the following configuration parameters IN ADDITION to specifying the test parameter on the command line. The test configuration in a project should ALWAYS specify a UNIQUE mongodb database.
// Always specify a unique mongodb database for testing
bedrock.config.mongodb.name = 'my_project_test';
bedrock.config.mongodb.host = 'localhost';
bedrock.config.mongodb.port = 27017;
bedrock.config.mongodb.username = 'test'; // default: bedrock
bedrock.config.mongodb.password = 'password';
// drop collections on initialization
bedrock.config.mongodb.dropCollections.onInit = true;
// if 'onInit' is specified, 'collections' must also be specified
// if collections is an empty array, ALL collections will be dropped
bedrock.config.mongodb.dropCollections.collections = [];