Abstracting Features Into Custom Reverse Proxies

Or: Making Better Lemonade From Chaos

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Nick Muerdter • RubyConf 2012 • November 1, 2012

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OKAY, BUT…

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WHY & HOW

A Story…

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6789204118

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Users Don’t Care

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• 1 entry point to all our APIs• 1 user account for all our APIs

• API key access to all our APIs• Rate limiting for all our APIs• Analytics for all our APIs

What We Wanted

• Changes required to each API

What We Didn’t Want

CUSTOMREVERSE

PROXY!!!

Better Lemonade?

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• 1 API key for all our services• Shielded from our internal

complexities

For API Users

• Old APIs: Do absolutely nothing• New APIs: Do absolutely nothing

• Get for free:–Authentication–Rate Limiting–Analytics

For Our Developers

• Reduced implementation code• Standardization is enforced• New features in the reverse proxy

benefit everyone• Reverse proxies can also be used

for scaling

Building these things…

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2179849680

• Ruby & EventMachine• Blazing fast• Flexible• Low-level

em-proxy

Proxy.start(:host => "0.0.0.0", :port => 80) do |conn| conn.server :srv, :host => "127.0.0.1", :port => 81

conn.on_data do |data| # Do something with the incoming data... data end

conn.on_response do |backend, resp| # Do something with the response... resp end

conn.on_finish do |backend, name| # Do something when finished... endend

conn.on_data do |data| # Modify the User-Agent on the incoming # request data.gsub(/User-Agent: .*?\r\n/, "User-Agent: em-proxy/0.1\r\n")end

redis = Redis.new(:host => "127.0.0.1")

conn.on_data do |data| # Fun things with Ruby! ip = peer[0] redis.incr(ip)

dataend

parser = Http::Parser.newparser.on_headers_complete = proc do |h| # Hello, friendlier HTTP headers... puts h["User-Agent"]end

conn.on_data do |data| parser << data dataend

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Transparency

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Speed & Efficiency

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Direct em-proxy rack-reverse-proxy0

0.5

1

1.5

2

2.5

3

3.5

4

Tim

e (m

illis

econ

ds)

(Terribly unscientific benchmarks)

Direct em-proxy rack-reverse-proxy1400

1500

1600

1700

1800

1900

2000

2100

2200

2300

2400

Tim

e (m

illis

econ

ds)

(Terribly unscientific benchmarks)

Flexibility

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What Else Can You Do?

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• Error handling?• Web page manipulation?

– Insert standard analytics JavaScript snippet?– Add a standard header and footer?

• Add JSONP callbacks for all JSON APIs?• Security checks?• More than HTTP…

– Intercept & manipulate e-mail?– Intercept & manipulate database calls?

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Buffering

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Content-Length

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gzip

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Want Bigger?

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WEBSERVICESBONANZA

• Make it easier for users to find and consume federal APIs

• Make it easier for federal agencies to develop & deploy more APIs

Main Objectives

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Same Problem

Same Solution?

Stay Tuned…

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SO………

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• Reverse Proxies: Fun for the whole family!

• Custom Reverse Proxies: You might be able to implement more functionality at this layer than you realize.

• Think Different: They can provide a different way to architect some features of your apps.

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Resources & Support

• Our full API management solution– Includes custom Event Machine based proxy

• Open source

API Umbrella

https://github.com/NREL/api-umbrella

(Just recently open sourced, so pardon the current state of things)

• em-proxy– https://github.com/igrigorik/em-proxy– Simple and very capable

• ProxyMachine– https://github.com/mojombo/proxymachine– Simpler, but can only act on requests, not responses

• Goliath– https://github.com/postrank-labs/goliath– More of a framework, uses em-synchrony (Fibers)

Ruby & Event Machine

• HAProxy– http://haproxy.1wt.eu/– General proxy and load balancing awesomeness

• Varnish Cache– https://www.varnish-cache.org/– Proxy caching layer coolness

• nginx– http://nginx.org/– Web server powerhouse and nice proxy

Other Reverse Proxies

• http://developer.nrel.gov/

Renewable Energy APIs

(Lots more APIs coming soon)

nick.muerdter@nrel.gov

@nickblah

http://bit.ly/rubystache

Enjoyed this presentation? Enjoyed this ‘stache?

Enjoy charity?

nick.muerdter@nrel.gov @nickblah