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Is
EventMachine
a worthy alternative to
Node.js
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Andrew Nesbitt
github.com/andrew
@teabass
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forwardtechnology.co.uk
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Node.js
nodejs.org
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"Evented I/O for V8 JavaScript"
Concurrent, scalable network programs
Speaks HTTP natively
Asynchronous, non-blocking by design
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"Realtime" applications
Proxy servers
Web APIs
What would you use it for?
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Synchronous I/O
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Asynchronous I/O
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var p_client = new Db('integration_tests_20', new Server("127.0.0.1", 27017, {}),
{'pk':CustomPKFactory});
p_client.open(function(err, p_client) {
p_client.dropDatabase(function(err, done) {
p_client.createCollection('test_custom_key', function(err, collection) {
collection.insert({'a':1}, function(err, docs) {
collection.find({'_id':new ObjectID("aaaaaaaaaaaa")}, function(err, cursor) {
cursor.toArray(function(err, items) {
test.assertEquals(1, items.length);
// Let's close the db
p_client.close();
});
});
});
});
});
});
Callback hell
gist.github.com/1309020
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EventMachine
github.com/eventmachine/eventmachine
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"Realtime" applications
Proxy servers
Web APIs
What would you use it for?
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Goliath
github.com/postrank-labs/goliath
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Rack API
Middleware support
Ruby fibers
No callback hell
1.9.2, jruby, rubinius
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Fight!
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Hello world
github.com/andrew/helloworlds
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Rack Example
class HelloWorld
def call(env)
[200, {'Content-Type' => 'text/html'}, ["Hello Rack"]]
end
end
run HelloWorld.new
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Node.js Example
var http = require('http');
http.createServer(function (req, res) {
res.writeHead(200, {'Content-Type': 'text/plain'});
res.end('Hello Node\n');
}).listen(9292, "127.0.0.1");
console.log('Server running at http://127.0.0.1:9292/');
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EventMachine Example
require 'rubygems'
require 'eventmachine'
require 'evma_httpserver'
class HelloWorld < EM::Connection
include EM::HttpServer
def post_init
super
no_environment_strings
end
def process_http_request
response = EM::DelegatedHttpResponse.new(self)
response.status = 200
response.content_type 'text/html'
response.content = 'Hello EventMachine'
response.send_response
end
end
EM.run{
EM.start_server '0.0.0.0', 9292, HelloWorld
}
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Goliath Example
require 'rubygems'
require 'goliath'
class Proxy < Goliath::API
def response(env)
[200, {}, "Hello Goliath"]
end
end
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Rack Example
class HelloWorld
def call(env)
[200, {'Content-Type' => 'text/html'}, ["Hello Rack"]]
end
end
run HelloWorld.new
require 'rubygems'
require 'goliath'
class Proxy < Goliath::API
def response(env)
[200, {}, "Hello Goliath"]
end
end
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rack => 423
goliath => 2125
node => 6084
em => 8814
Performance (requests/s)
ab -n 1000 -c 100 http://localhost:9000/
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URL Shortener
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var http = require('http'),
connect = require('connect'),
redis = require("redis"),
client = redis.createClient(),
b62 = require('base62');
var server = connect.createServer(connect.query());
server.use('/',
connect.router(function(app){
app.get('/', function(req, res, next){
res.writeHead(200, {'Content-Type': 'text/html'});
if (req.query.url){
client.keys('*',function(err, result){
key = b62.encode(result.length)
client.set(key, req.query.url, function(err, result){
res.write('http://localhost:9000/'+key)
res.end()
});
});
} else {
res.write('Hi')
res.end()
}
});
app.get('/:key', function(req, res, next){
client.get(req.params.key, function(err, result){
res.writeHead(302, {'Location': result});
res.end()
});
});
})
);
server.listen(9000);
console.log('Server running at http://127.0.0.1:9000/');
Node Example
github.com/andrew/node-shortener
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class Shortener < EM::Connection
include EM::HttpServer
attr_reader :http_request_uri, :http_query_string
def post_init
super
no_environment_strings
end
def process_http_request
redis = EM::Protocols::Redis.connect
path = @http_request_uri.to_s
query = @http_query_string.to_s
response = EM::DelegatedHttpResponse.new(self)
case path
when '/'
if @http_query_string
params = URI.decode_www_form(query)
url = params.assoc('url').last.chomp
redis.keys '*' do |result|
key = result.size.base62_encode
redis.set key, url do |result|
response.status = 200
response.content_type 'text/html'
response.content = "http://localhost:9000/#{key}"
response.send_response
end
end
else
response.status = 200
response.content_type 'text/html'
response.content = 'Hi'
response.send_response
end
else
redis.get path[1..-1] do |result|
response.status = 302
response.headers["Location"] = result
response.send_response
end
end
end
end
EM.run{
EM.start_server '0.0.0.0', 9000, Shortener
}
EM Example
github.com/andrew/em-shortener
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REDIS = EventMachine::Synchrony::ConnectionPool.new(:size => 5) do
Redis.connect
end
class Redirect < Goliath::API
use Goliath::Rack::Params
def response(env)
url = REDIS.get params[:key]
if url
[302, {:location => url}, nil]
else
[404, {}, 'Not Found']
end
end
end
class Create < Goliath::API
use Goliath::Rack::Params
def response(env)
if params['url']
key = REDIS.keys.size.base62_encode
REDIS.set(key, params['url'])
[200, {}, "http://#{env['HTTP_HOST']}/#{key}"]
else
[200, {}, "Hi!"]
end
end
end
class Shortener < Goliath::API
map "/" do
run Create.new
end
map "/:key" do
run Redirect.new
end
end
Goliath Example
github.com/andrew/goliath-shortener
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goliath => 1048
node => 3660
em => 7943
Performance (requests/s)
ab -n 1000 -c 100 http://localhost:9000/2W
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Things to consider
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Testing
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vowsjs.org
github.com/tmm1/em-spec
Node
EM
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DSLs
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Sinatra
get '/hi' do
"Hello World!"
end
sinatrarb.com
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Express.js
app.get('/', function(req, res){
res.send('Hello World');
});
expressjs.com
app.get "/", (req, res) ->
res.send "Hello World"
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class HomeAction < Cramp::Action
def start
render "Hello World"
finish
end
end
Cramp
cramp.in
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Libraries
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Deployment
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Coffeescript
jashkenas.github.com/coffee-script
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var http = require('http'),
connect = require('connect'),
redis = require("redis"),
client = redis.createClient(),
b62 = require('base62');
var server = connect.createServer(connect.query());
server.use('/',
connect.router(function(app){
app.get('/', function(req, res, next){
res.writeHead(200, {'Content-Type': 'text/html'});
if (req.query.url){
client.keys('*',function(err, result){
key = b62.encode(result.length)
client.set(key, req.query.url, function(err, result){
res.write('http://localhost:9000/'+key)
res.end()
});
});
} else {
res.write('Hi')
res.end()
}
});
app.get('/:key', function(req, res, next){
client.get(req.params.key, function(err, result){
res.writeHead(302, {'Location': result});
res.end()
});
});
})
);
server.listen(9000);
console.log('Server running at http://127.0.0.1:9000/');
Node Example
github.com/andrew/node-shortener
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http = require("http")
connect = require("connect")
redis = require("redis")
client = redis.createClient()
b62 = require("base62")
server = connect.createServer(connect.query())
server.use "/", connect.router((app) ->
app.get "/", (req, res, next) ->
res.writeHead 200,
"Content-Type": "text/html"
if req.query.url
client.keys "*", (err, result) ->
key = b62.encode(result.length)
client.set key, req.query.url, (err, result) ->
res.write "http://localhost:9000/" + key
res.end()
else
res.write "Hi"
res.end()
app.get "/:key", (req, res, next) ->
client.get req.params.key, (err, result) ->
res.writeHead 302,
Location: result
res.end()
)
server.listen 9000
console.log "Server running at http://127.0.0.1:9000/"
Coffeescript Example
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Rails
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async-rails
github.com/igrigorik/async-rails
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Conclusion
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Node
Pros
Shared code between client and server
Vibrant Community
Lightning Fast
Cons
Javascript
Callback hell
Less mature
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EventMachine
Pros
It’s ruby!
Mature
Clever DSLs
Also fast
Cons
More difficult to write than normal ruby
Restricted to EM libraries
Not the new hotness
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Is
EventMachine
a worthy alternative to
Node.js
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Yes
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Node or EM are not a
magic bullets
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Go - http://golang.org/
Erlang - http://erlang.org/
Twisted - http://twistedmatrix.com
Other languages
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Fin.
speakerdeck.com/u/andrew/p/em-vs-node