dynogels-lambda
dynogels-lambda is a DynamoDB data mapper for node.js. This project has been forked from
Dynogels and republished to npm under a different name in order
to support a smaller lambda function build.
Features
Installation
npm install dynogels
Getting Started
First, you need to configure the AWS SDK with your credentials.
var dynogels = require('dynogels');
dynogels.AWS.config.loadFromPath('credentials.json');
When running on EC2 it's recommended to leverage EC2 IAM roles. If you have configured your instance to use IAM roles,
Vogels will automatically select these credentials for use in your application,
and you do not need to manually provide credentials in any other format.
var dynogels = require('dynogels');
dynogels.AWS.config.update({region: "REGION"});
You can also directly pass in your access key id, secret and region.
- It's recommended not to hard-code credentials inside an application.
Use this method only for small personal scripts or for testing purposes.
var dynogels = require('dynogels');
dynogels.AWS.config.update({accessKeyId: 'AKID', secretAccessKey: 'SECRET', region: "REGION"});
Currently the following region codes are available in Amazon:
Code | Name |
---|
ap-northeast-1 | Asia Pacific (Tokyo) |
ap-southeast-1 | Asia Pacific (Singapore) |
ap-southeast-2 | Asia Pacific (Sydney) |
eu-central-1 | EU (Frankfurt) |
eu-west-1 | EU (Ireland) |
sa-east-1 | South America (Sao Paulo) |
us-east-1 | US East (N. Virginia) |
us-west-1 | US West (N. California) |
us-west-2 | US West (Oregon) |
Define a Model
Models are defined through the toplevel define method.
var Account = dynogels.define('Account', {
hashKey : 'email',
timestamps : true,
schema : {
email : Joi.string().email(),
name : Joi.string(),
age : Joi.number(),
roles : dynogels.types.stringSet(),
settings : {
nickname : Joi.string(),
acceptedTerms : Joi.boolean().default(false)
}
}
});
Models can also be defined with hash and range keys.
var BlogPost = dynogels.define('BlogPost', {
hashKey : 'email',
rangeKey : ‘title’,
schema : {
email : Joi.string().email(),
title : Joi.string(),
content : Joi.binary(),
tags : dynogels.types.stringSet(),
}
});
You can pass through validation options to Joi like so:
var BlogPost = dynogels.define('BlogPost', {
hashKey : 'email',
rangeKey : 'title',
schema : {
email : Joi.string().email(),
title : Joi.string()
},
validation: {
allowUnknown: true
}
});
Create Tables for all defined models
dynogels.createTables(function(err) {
if (err) {
console.log('Error creating tables: ', err);
} else {
console.log('Tables have been created');
}
});
When creating tables you can pass specific throughput settings or stream specification for any defined models.
dynogels.createTables({
'BlogPost': {readCapacity: 5, writeCapacity: 10},
'Account': {
readCapacity: 20,
writeCapacity: 4,
streamSpecification: {
streamEnabled: true,
streamViewType: 'NEW_IMAGE'
}
}
}, function(err) {
if (err) {
console.log('Error creating tables: ', err);
} else {
console.log('Tables has been created');
}
});
You can also pass operational options using the $dynogels
key:
pollingInterval
: When creating a table, Dynogels must poll the DynamoDB server to detect when table creation has completed. This option specifies the minimum poll interval, in milliseconds. (Default: 1000)
dynogels.createTables({
$dynogels: { pollingInterval: 100 }
}, function(err) {
if (err) {
console.log('Error creating tables: ', err);
} else {
console.log('Tables has been created');
}
});
Delete Table
BlogPost.deleteTable(function(err) {
if (err) {
console.log('Error deleting table: ', err);
} else {
console.log('Table has been deleted');
}
});
Schema Types
Vogels provides the following schema types:
- String
- Number
- StringSet
- NumberSet
- Boolean
- Date
- UUID
- TimeUUID
UUID
UUIDs can be declared for any attributes, including hash and range keys. By
Default, the uuid will be automatically generated when attempting to create
the model in DynamoDB.
var Tweet = dynogels.define('Tweet', {
hashKey : 'TweetID',
timestamps : true,
schema : {
TweetID : dynogels.types.uuid(),
content : Joi.string(),
}
});
Configuration
You can configure dynogels to automatically add createdAt
and updatedAt
timestamp attributes when
saving and updating a model. updatedAt
will only be set when updating a record
and will not be set on initial creation of the model.
var Account = dynogels.define('Account', {
hashKey : 'email',
timestamps : true,
schema : {
email : Joi.string().email(),
}
});
If you want dynogels to handle timestamps, but only want some of them, or want your
timestamps to be called something else, you can override each attribute individually:
var Account = dynogels.define('Account', {
hashKey : 'email',
timestamps : true,
createdAt: false,
updatedAt: 'updateTimestamp'
schema : {
email : Joi.string().email(),
}
});
You can override the table name the model will use.
var Event = dynogels.define('Event', {
hashKey : 'name',
schema : {
name : Joi.string(),
total : Joi.number()
},
tableName: 'deviceEvents'
});
if you set the tableName to a function, dynogels will use the result of the function as the active table to use.
Useful for storing time series data.
var Event = dynogels.define('Event', {
hashKey : 'name',
schema : {
name : Joi.string(),
total : Joi.number()
},
tableName: function () {
var d = new Date();
return ['events', d.getFullYear(), d.getMonth() + 1].join('_');
}
});
After you've defined your model you can configure the table name to use.
By default, the table name used will be the lowercased and pluralized version
of the name you provided when defining the model.
Account.config({tableName: 'AccountsTable'});
You can also pass in a custom instance of the aws-sdk DynamoDB client
var dynamodb = new AWS.DynamoDB();
Account.config({dynamodb: dynamodb});
dynogels.dynamoDriver(dynamodb);
Saving Models to DynamoDB
With your models defined, we can start saving them to DynamoDB.
Account.create({email: 'foo@example.com', name: 'Foo Bar', age: 21}, function (err, acc) {
console.log('created account in DynamoDB', acc.get('email'));
});
You can also first instantiate a model and then save it.
var acc = new Account({email: 'test@example.com', name: 'Test Example'});
acc.save(function (err) {
console.log('created account in DynamoDB', acc.get('email'));
});
Saving models that require range and hashkeys are identical to ones with only
hashkeys.
BlogPost.create({
email: 'werner@example.com',
title: 'Expanding the Cloud',
content: 'Today, we are excited to announce the limited preview...'
}, function (err, post) {
console.log('created blog post', post.get('title'));
});
Pass an array of items and they will be saved in parallel to DynamoDB.
var item1 = {email: 'foo1@example.com', name: 'Foo 1', age: 10};
var item2 = {email: 'foo2@example.com', name: 'Foo 2', age: 20};
var item3 = {email: 'foo3@example.com', name: 'Foo 3', age: 30};
Account.create([item1, item2, item3], function (err, acccounts) {
console.log('created 3 accounts in DynamoDB', accounts);
});
Use expressions api to do conditional writes
var params = {};
params.ConditionExpression = '#i <> :x';
params.ExpressionAttributeNames = {'#i' : 'id'};
params.ExpressionAttributeValues = {':x' : 123};
User.create({id : 123, name : 'Kurt Warner' }, params, function (error, acc) { ... });
Use the overwrite
option to prevent over writing of existing records.
- By default
overwrite
is set to true, allowing create operations to overwrite existing records
User.create({id : 123, name : 'Kurt Warner' }, {overwrite : false}, function (error, acc) { ... });
Updating
When updating a model the hash and range key attributes must be given, all
other attributes are optional
Account.update({email: 'foo@example.com', name: 'Bar Tester'}, function (err, acc) {
console.log('update account', acc.get('name'));
});
Model.update
accepts options to pass to DynamoDB when making the updateItem request
Account.update({email: 'foo@example.com', name: 'Bar Tester'}, {ReturnValues: 'ALL_OLD'}, function (err, acc) {
console.log('update account', acc.get('name'));
});
Account.update({email: 'foo@example.com', name: 'Bar Tester'}, {expected: {age: 22}}, function (err, acc) {
console.log('update account', acc.get('name'));
});
Account.update({email: 'foo@example.com', age: null}, function (err, acc) {
console.log('update account', acc.get('age'));
});
To ensure that an item exists before updating, use the expected
parameter to check the existence of the hash key. The hash key must exist for every DynamoDB item. This will return an error if the item does not exist.
Account.update(
{ email: 'foo@example.com', name: 'FooBar Testers' },
{ expected: { email: { Exists: true } } },
(err, acc) => {
console.log(acc.get('name'));
}
);
Account.update(
{ email: 'baz@example.com', name: 'Bar Tester' },
{ expected: { email: { Exists: true } } },
(err, acc) => {
console.log(err);
}
);
This is essentially short-hand for:
var params = {};
params.ConditionExpression = 'attribute_exists(#hashKey)';
params.ExpressionAttributeNames = { '#hashKey' : 'email' };
You can also pass what action to perform when updating a given attribute
Use $add to increment or decrement numbers and add values to sets
Account.update({email : 'foo@example.com', age : {$add : 1}}, function (err, acc) {
console.log('incremented age by 1', acc.get('age'));
});
BlogPost.update({
email : 'werner@example.com',
title : 'Expanding the Cloud',
tags : {$add : 'cloud'}
}, function (err, post) {
console.log('added single tag to blog post', post.get('tags'));
});
BlogPost.update({
email : 'werner@example.com',
title : 'Expanding the Cloud',
tags : {$add : ['cloud', 'dynamodb']}
}, function (err, post) {
console.log('added tags to blog post', post.get('tags'));
});
$del will remove values from a given set
BlogPost.update({
email : 'werner@example.com',
title : 'Expanding the Cloud',
tags : {$del : 'cloud'}
}, function (err, post) {
console.log('removed cloud tag from blog post', post.get('tags'));
});
BlogPost.update({
email : 'werner@example.com',
title : 'Expanding the Cloud',
tags : {$del : ['aws', 'node']}
}, function (err, post) {
console.log('removed multiple tags', post.get('tags'));
});
Use the expressions api to update nested documents
var params = {};
params.UpdateExpression = 'SET #year = #year + :inc, #dir.titles = list_append(#dir.titles, :title), #act[0].firstName = :firstName ADD tags :tag';
params.ConditionExpression = '#year = :current';
params.ExpressionAttributeNames = {
'#year' : 'releaseYear',
'#dir' : 'director',
'#act' : 'actors'
};
params.ExpressionAttributeValues = {
':inc' : 1,
':current' : 2001,
':title' : ['The Man'],
':firstName' : 'Rob',
':tag' : dynogels.Set(['Sports', 'Horror'], 'S')
};
Movie.update({title : 'Movie 0', description : 'This is a description'}, params, function (err, mov) {});
Deleting
You delete items in DynamoDB using the hashkey of model
If your model uses both a hash and range key, then both need to be provided
Account.destroy('foo@example.com', function (err) {
console.log('account deleted');
});
BlogPost.destroy('foo@example.com', 'Hello World!', function (err) {
console.log('post deleted')
});
BlogPost.destroy({email: 'foo@example.com', title: 'Another Post'}, function (err) {
console.log('another post deleted')
});
Model.destroy
accepts options to pass to DynamoDB when making the deleteItem request
Account.destroy('foo@example.com', {ReturnValues: 'ALL_OLD'}, function (err, acc) {
console.log('account deleted');
console.log('deleted account name', acc.get('name'));
});
Account.destroy('foo@example.com', {expected: {age: 22}}, function (err) {
console.log('account deleted if the age was 22');
});
Use expression apis to perform conditional deletes
var params = {};
params.ConditionExpression = '#v = :x';
params.ExpressionAttributeNames = {'#v' : 'version'};
params.ExpressionAttributeValues = {':x' : '2'};
User.destroy({id : 123}, params, function (err, acc) {});
Loading models from DynamoDB
The simpliest way to get an item from DynamoDB is by hashkey.
Account.get('test@example.com', function (err, acc) {
console.log('got account', acc.get('email'));
});
Perform the same get request, but this time peform a consistent read.
Account.get('test@example.com', {ConsistentRead: true}, function (err, acc) {
console.log('got account', acc.get('email'));
});
Model.get
accepts any options that DynamoDB getItem request supports. For
example:
Account.get('test@example.com', {ConsistentRead: true, AttributesToGet : ['name','age']}, function (err, acc) {
console.log('got account', acc.get('email'))
console.log(acc.get('name'));
console.log(acc.get('age'));
console.log(acc.get('email'));
});
Get a model using hash and range key.
BlogPost.get('werner@example.com', 'dynamodb-keeps-getting-better-and-cheaper', function (err, post) {
console.log('loaded post by range and hash key', post.get('content'));
});
Model.get
also supports passing an object which contains hash and range key
attributes to load up a model
BlogPost.get({email: 'werner@example.com', title: 'Expanding the Cloud'}, function (err, post) {
console.log('loded post', post.get('content'));
});
Use expressions api to select which attributes you want returned
User.get({ id : '123456789'},{ ProjectionExpression : 'email, age, settings.nickname' }, function (err, acc) {});
Query
For models that use hash and range keys Vogels provides a flexible and
chainable query api
BlogPost
.query('werner@example.com')
.exec(callback);
BlogPost
.query('werner@example.com')
.loadAll()
.exec(callback);
BlogPost
.query('werner@example.com')
.limit(5)
.exec(callback);
BlogPost
.query('werner@example.com')
.where('title').beginsWith('Expanding')
.exec(callback);
BlogPost
.query('werner@example.com')
.where('title').beginsWith('Expanding')
.select('COUNT')
.exec(callback);
BlogPost
.query('werner@example.com')
.where('title').beginsWith('Expanding')
.attributes(['title', 'content'])
.limit(10)
.exec(callback);
BlogPost
.query('werner@example.com')
.ascending()
.exec(callback)
BlogPost
.query('werner@example.com')
.descending()
.exec(callback)
BlogPost
.query('werner@example.com')
.where('title').gt('Expanding')
.attributes(['title', 'content'])
.limit(10)
.ascending()
.loadAll()
.exec(callback);
Account
.query('werner@example.com')
.filter('settings.acceptedTerms').equals(true)
.exec(callback);
Warning, limit is applied first before the where filter. The limit value limits the scanned count,
not the number of returned items. See #12
Vogels supports all the possible KeyConditions that DynamoDB currently
supports.
BlogPost
.query('werner@example.com')
.where('title').equals('Expanding')
.exec();
BlogPost
.query('werner@example.com')
.where('title').lte('Expanding')
.exec();
BlogPost
.query('werner@example.com')
.where('title').lt('Expanding')
.exec();
BlogPost
.query('werner@example.com')
.where('title').gt('Expanding')
.exec();
BlogPost
.query('werner@example.com')
.where('title').gte('Expanding')
.exec();
BlogPost
.query('werner@example.com')
.where('title').null()
.exec();
BlogPost
.query('werner@example.com')
.where('title').exists()
.exec();
BlogPost
.query('werner@example.com')
.where('title').beginsWith('Expanding')
.exec();
BlogPost
.query('werner@example.com')
.where('title').between('foo@example.com', 'test@example.com')
.exec();
Query Filters allow you to further filter results on non-key attributes.
BlogPost
.query('werner@example.com')
.where('title').equals('Expanding')
.filter('tags').contains('cloud')
.exec();
Expression Filters also allow you to further filter results on non-key attributes.
BlogPost
.query('werner@example.com')
.filterExpression('#title < :t')
.expressionAttributeValues({ ':t' : 'Expanding' })
.expressionAttributeNames({ '#title' : 'title'})
.projectionExpression('#title, tag')
.exec();
See the queryFilter.js example for more examples of using query filters
Global Indexes
First, define a model with a global secondary index.
var GameScore = dynogels.define('GameScore', {
hashKey : 'userId',
rangeKey : 'gameTitle',
schema : {
userId : Joi.string(),
gameTitle : Joi.string(),
topScore : Joi.number(),
topScoreDateTime : Joi.date(),
wins : Joi.number(),
losses : Joi.number()
},
indexes : [{
hashKey : 'gameTitle', rangeKey : 'topScore', name : 'GameTitleIndex', type : 'global'
}]
});
Now we can query against the global index
GameScore
.query('Galaxy Invaders')
.usingIndex('GameTitleIndex')
.descending()
.exec(callback);
When can also configure the attributes projected into the index.
By default all attributes will be projected when no Projection pramater is
present
var GameScore = dynogels.define('GameScore', {
hashKey : 'userId',
rangeKey : 'gameTitle',
schema : {
userId : Joi.string(),
gameTitle : Joi.string(),
topScore : Joi.number(),
topScoreDateTime : Joi.date(),
wins : Joi.number(),
losses : Joi.number()
},
indexes : [{
hashKey : 'gameTitle',
rangeKey : 'topScore',
name : 'GameTitleIndex',
type : 'global',
projection: { NonKeyAttributes: [ 'wins' ], ProjectionType: 'INCLUDE' }
}]
});
Filter items against the configured rangekey for the global index.
GameScore
.query('Galaxy Invaders')
.usingIndex('GameTitleIndex')
.where('topScore').gt(1000)
.descending()
.exec(function (err, data) {
console.log(_.map(data.Items, JSON.stringify));
});
Local Secondary Indexes
First, define a model using a local secondary index
var BlogPost = dynogels.define('Account', {
hashKey : 'email',
rangeKey : 'title',
schema : {
email : Joi.string().email(),
title : Joi.string(),
content : Joi.binary(),
PublishedDateTime : Joi.date()
},
indexes : [{
hashKey : 'email', rangeKey : 'PublishedDateTime', type : 'local', name : 'PublishedIndex'
}]
});
Now we can query for blog posts using the secondary index
BlogPost
.query('werner@example.com')
.usingIndex('PublishedIndex')
.descending()
.exec(callback);
Could also query for published posts, but this time return oldest first
BlogPost
.query('werner@example.com')
.usingIndex('PublishedIndex')
.ascending()
.exec(callback);
Finally lets load all published posts sorted by publish date
BlogPost
.query('werner@example.com')
.usingIndex('PublishedIndex')
.descending()
.loadAll()
.exec(callback);
Learn more about secondary indexes
Scan
Vogels provides a flexible and chainable api for scanning over all your items
This api is very similar to the query api.
Account.scan().exec(callback);
Account
.scan()
.loadAll()
.exec(callback);
Account
.scan()
.limit(20)
.exec();
Account
.scan()
.limit(20)
.loadAll()
.exec();
Account
.scan()
.where('email').gte('f@example.com')
.attributes(['email','created'])
.returnConsumedCapacity()
.exec();
Account
.scan()
.where('settings.acceptedTerms').equals(true)
.exec();
Account
.scan()
.where('age').gte(21)
.select('COUNT')
.exec();
Account
.scan()
.where('age').notNull()
.startKey('foo@example.com')
.exec()
Vogels supports all the possible Scan Filters that DynamoDB currently supports.
Account
.scan()
.where('name').equals('Werner')
.exec();
Account
.scan()
.where('name').ne('Werner')
.exec();
Account
.scan()
.where('name').lte('Werner')
.exec();
Account
.scan()
.where('name').lt('Werner')
.exec();
Account
.scan()
.where('name').gte('Werner')
.exec();
Account
.scan()
.where('name').gt('Werner')
.exec();
Account
.scan()
.where('name').null()
.exec();
Account
.scan()
.where('name').notNull()
.exec();
Account
.scan()
.where('name').contains('ner')
.exec();
Account
.scan()
.where('name').notContains('ner')
.exec();
Account
.scan()
.where('name').in(['foo@example.com', 'bar@example.com'])
.exec();
Account
.scan()
.where('name').beginsWith('Werner')
.exec();
Account
.scan()
.where('name').between('Bar', 'Foo')
.exec();
Account
.scan()
.where('name').equals('Werner')
.where('age').notNull()
.exec();
You can also use the new expressions api when filtering scans
User.scan()
.filterExpression('#age BETWEEN :low AND :high AND begins_with(#email, :e)')
.expressionAttributeValues({ ':low' : 18, ':high' : 22, ':e' : 'test1'})
.expressionAttributeNames({ '#age' : 'age', '#email' : 'email'})
.projectionExpression('#age, #email')
.exec();
Parallel Scan
Parallel scans increase the throughput of your table scans.
The parallel scan operation is identical to the scan api.
The only difference is you must provide the total number of segments
Caution you can easily consume all your provisioned throughput with this api
var totalSegments = 8;
Account.parallelScan(totalSegments)
.where('age').gte(18)
.attributes('age')
.exec(callback);
Account
.parallelScan(totalSegments)
.exec()
More info on Parallel Scans
Batch Get Items
Model.getItems
allows you to load multiple models with a single request to DynamoDB.
DynamoDB limits the number of items you can get to 100 or 1MB of data for a single request.
Vogels automatically handles splitting up into multiple requests to load all
items.
Account.getItems(['foo@example.com','bar@example.com', 'test@example.com'], function (err, accounts) {
console.log('loaded ' + accounts.length + ' accounts');
});
var postKey1 = {email : 'test@example.com', title : 'Hello World!'};
var postKey2 = {email : 'test@example.com', title : 'Another Post'};
BlogPost.getItems([postKey1, postKey2], function (err, posts) {
console.log('loaded posts');
});
Model.getItems
accepts options which will be passed to DynamoDB when making the batchGetItem request
Account.getItems(['foo@example.com','bar@example.com'], {ConsistentRead: true}, function (err, accounts) {
console.log('loaded ' + accounts.length + ' accounts');
});
Streaming api
dynogels supports a basic streaming api in addition to the callback
api for query
, scan
, and parallelScan
operations.
var stream = Account.parallelScan(4).exec();
stream.on('readable', function () {
console.log('single parallel scan response', stream.read());
});
stream.on('end', function () {
console.log('Parallel scan of accounts finished');
});
var querystream = BlogPost.query('werner@dynogels.com').loadAll().exec();
querystream.on('readable', function () {
console.log('single query response', stream.read());
});
querystream.on('end', function () {
console.log('query for blog posts finished');
});
Dynamic Table Names
dynogels supports dynamic table names, useful for storing time series data.
var Event = dynogels.define('Event', {
hashKey : 'name',
schema : {
name : Joi.string(),
total : Joi.number()
},
tableName: function () {
var d = new Date();
return ['events', d.getFullYear(), d.getMonth() + 1].join('_');
}
});
Logging
A logger that implements info
and warn
methods (e.g Bunyan or Winston)
can be provided to either dynogels itself or individual models:
const logger = require('winston');
logger.level = 'warn';
dynogels.log = logger;
const accountLogger = require('winston');
accountLogger.level = 'info';
var Account = dynogels.define('Account', {
hashKey: 'email',
log: accountLogger
});
Examples
var dynogels = require('dynogels');
var Account = dynogels.define('Account', {
hashKey : 'email',
timestamps : true,
schema : {
email : Joi.string().email(),
name : Joi.string().required(),
age : Joi.number(),
}
});
Account.create({email: 'test@example.com', name : 'Test Account'}, function (err, acc) {
console.log('created account at', acc.get('created'));
acc.set({age: 22});
acc.update(function (err) {
console.log('updated account age');
});
});
See the examples for more working sample code.
Support
Dynogels is provided as-is, free of charge. For support, you have a few choices:
- Ask your support question on Stackoverflow.com, and tag your question with dynogels.
- If you believe you have found a bug in dynogels, please submit a support ticket on
the Github Issues page for dynogels. We'll get to them as soon as we can.
- For general feedback message me on twitter
- For more personal or immediate support, I’m available for hire to consult on your project.
Contact me for more detals.
Maintainers
License
(The MIT License)
Copyright (c) 2016 Ryan Fitzgerald
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
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