Programmable proxies enable devops patterns and introduce flexibility into the network.

1. PROGRAMMING PROXIES
TO DO WHAT WE NEED SO
WE DON'T HAVE TO TALK
TO THE NETWORK GUYS
AGAIN
@lmacvittie from @f5networks at #gluecon
Lori MacVittie
Sr. Product Manager, Emerging Technologies
F5 Networks

2. Deployment
patterns
WHY WOULD YOU NEED
TO TALK TO THE
NETWORK GUYS
ANYWAY?
@lmacvittie #gluecon

3. DEPLOYMENT PATTERNS USE LAYER 7 ROUTING
Canary Deployments Blue/Green Deployments
A/B Testing
v.1
v.2
v.3
API Management
Redirection Replication
(Dark Architecture)
@lmacvittie #gluecon

4. ROUTING IS A NETWORK THING
Router Switch FirewallDDoS Protection Load BalancingDNS
CORE NETWORK (SHARED)
THE NETWORK GUYS ARE GENERALLY RESPONSIBLE FOR LAYER 7 ROUTING
@lmacvittie #gluecon

5. THEY DON’T WANT YOU TOUCHING THEIR TOYS
@lmacvittie #gluecon

6. proxiesSO WHAT DO YOU DO?
@lmacvittie #gluecon

7. Go forward and
backwards.
PROXIES
A Reverse Proxy sits between the user and an
application and can do things like caching, load
balancing, and security on behalf of the app.
A Forward Proxy sits between the user and an
application and does things like caching and
stopping you from using Facebook at work.
Today we’re (mostly) talking about the Reverse kind of Proxy.
@lmacvittie #gluecon

8. Proxies are
application-
aware with
network chops.
They are fluent
in both the
language of
applications
and networks.
PROXIES
THIS IS WHERE NETWORK STUFFS LIVE
THIS IS WHERE PROXIES LIVE
THIS IS WHERE APPLICATIONS LIVE
DATA
NETWORK
TRANSPORT
SESSION
PRESENTATION
APPLICATION
MAC ADDRESS
IP ADDRESS
TCP
SOCKS
SSL
HTTP / SPDY
L2-3 SERVICES
L4-7 SERVICES
HTML JSON XMLCSS
@lmacvittie #gluecon

9. WEB SERVER
PROXY
MODEL
VERSUS
PROGRAMMABLE
PROXY
MODEL
Proxy
Code
Config
Web Server Proxy Model
Application Stuffs
Network Stuffs
Programmable Proxy Model
Proxy
Code
Config
Application Stuffs
Network Stuffs
@lmacvittie #gluecon

10. A programmable
proxy is a proxy
that lets you
write code that
interacts with
both application
and network
stuffs like load
balancing and
application (L7)
routing and
databases.
PROGRAMMABLE
PROXIES
var onRequest = function(request, response, next ) {
var cookie = new Cookies( request, response );
var bugz_login = cookie.get("Bugzilla_login");
if( !logged_in || !bugz_login ) {
vs_a.newRequest(request, response, next);
return;
}
connection.query('SELECT opt_in from abtest where
userid=' + bugz_login, function(err, rows, fields) {
if (err) throw err;
var opt_in = rows[0].opt_in;
if( !opt_in ) {
vs_a.newRequest(request, response, next);
return;
} else {
vs_b.newRequest(request, response, next);
return;
}
});
Bugzilla
Bugzilla-A
Bugzilla-B
APPLICATION
STUFFS
NETWORK
STUFFS
@lmacvittie #gluecon

11. Deployment
patterns with
programmable
proxies
EXAMPLES
@lmacvittie #gluecon

12. A/B TESTING
Devices
Internet
Service Pool A
Service Pool B
serverGroupA
serverGroupB
vs1
vs2
• Transparently direct users to either version “A” or version “B”
• Increase or decrease traffic to each version in an instant
• Customize the selection criteria to your needs with a short Node.js script
• Use resources like databases or web APIs as part of the decision
@lmacvittie #gluecon
MySQL
Database

13. var assert = require('assert');
var os = require('os');
var http = require('http');
var fpm = require('lrs/forwardProxyModule');
var vsm = require('lrs/virtualServerModule');
var mysql = require('mysql');
var Cookies = require('cookies');
var proxyhost = os.hostname();
var vs = vsm.find('Bugzilla');
var vs_a = vsm.find('Bugzilla-A');
var vs_b = vsm.find('Bugzilla-B');
var logged_in = false;
// Log to a database
var connection = mysql.createConnection({
host : '192.168.22.22',
user : ‘xxxx',
password : ‘yyyyyyyyy',
database : 'abtesting'
});
var onRequest = function(request, response, next ) {
var cookie = new Cookies( request, response );
var bugz_login = cookie.get("Bugzilla_login");
if( !logged_in || !bugz_login ) {
// Default action: Send to A
vs_a.newRequest(request, response, next);
return;
}
// Add the user to the database automatically if they don't already exist
connection.query('INSERT INTO abtest (userid, ip) select * FROM (SELECT ' +
bugz_login + ', "' + request.connection.remoteAddress + '") as tmp
WHERE NOT EXISTS(SELECT userid from abtest where userid=' +
bugz_login + ')', function(err, rows, fields) {
if (err) throw err;
// Use the database to decide which server to send this request to
connection.query('SELECT opt_in from abtest where userid=' + bugz_login,
function(err, rows, fields) {
if (err) throw err;
var opt_in = rows[0].opt_in;
if( !opt_in ) { vs_a.newRequest(request, response, next);
return;
} else { vs_b.newRequest(request, response, next);
return;
}
});
});
};
// onRequest
var onExist = function(vs) {
if(vs.id == 'Bugzilla') {
vs.on('request', onRequest);
connection.connect();
logged_in = true;
setInterval(keepAlive, 60000);
}
};
vsm.on('exist', 'Bugzilla', onExist);

14. URI MANAGEMENT (REDIRECTION)
Devices
Internet
• Manage hundreds of redirects/rewrites
(www.example.com/app2  www.example.com/app/v2)
• Update redirects without incurring potential outages
• Turn over management to the business folks because updating http conf files
every other day isn’t exactly the job you signed up for @lmacvittie #gluecon
serverGroupA
serverGroupB
vs1
vs2

15. TRAFFIC REPLICATION
Devices
Internet
Production
Staging
serverGroupA
serverGroupB
LB
LB
• Selected requests are replicated to both environments
• Selection criteria can be custom logic or network or application variables
@lmacvittie #gluecon

16. TRAFFIC REPLICATION
Devices
Internet
Production
Staging
serverGroupA
serverGroupB
LB
LB
• Production response flows back to user immediately
• Staging response is blocked from clients
• Custom code can compare production and staging response, report errors,
slowness, etc. and can log for later analysis @lmacvittie #gluecon

17. function forwardRequest(request, response, next) {
"use strict";
var vsm = require('lrs/virtualServerModule');
var http = require('http');
var mgmt = require('lrs/managementRest');
function ReplicateTraffic(scenarioName, primaryVSName, secondaryPort) {
var self = this;
self.scenarioName = scenarioName;
self.primaryVS = primaryVSName;
self.port = secondaryPort;
//We need a secondary port that we expect is a loopback virtual IP that
//goes to the secondary virtual server
vsm.on('exist', primaryVSName, function(vs) {
vs.on('request', function(req, res, next) {
self.replicate(req, res, next);
});
});
}
ReplicateTraffic.prototype.cloneReq = function(req) {
var newReq = http.request({ host: "127.0.0.1",
port: this.port,
method: req.method,
path: req.url,
headers: req.headers},
function() {});
return newReq;
}
ReplicateTraffic.prototype.replicate = function(req, res, next) {
if(req.method == 'GET' || req.method == 'HEAD') {
// Only do GET and HEAD
var newReq = this.cloneReq(req);
// I want to do vsB.newRequest(newReq) but cannot
// so I loop it through a dummy vip in cloneReq
newReq.on('response', function(res)
{ console.log('saw B resp'); });
newReq.end();
}
next();
}
var repl = new ReplicateTraffic("xxx",
'vsAandB',
15000);

18. Network
stuffs
belong in
the network.
WHEN SHOULD I USE A
PROGRAMMABLE
PROXY?
@lmacvittie #gluecon

19. How to choose
between proxy
and app
NETWORK
STUFFS
• chooses an application instance based on HTTP header
• Content-type, URI, device (user-agent), API version, HTTP
CRUD operation, etc…
• chooses an application instance based on payload
• Value of a key in a JSON payload, XML element value,
HTML form data, etc…
• would force you to use an HTTP redirect
• Changing URLs
• Deprecated API calls
• is enforcing a quota (rate limiting) to avoid overwhelming
applications
• needs to do a network thing (e.g. app routing, load balancing,
service chaining) that requires application data from an
external source (database, API call, etc…)
Put the logic in a proxy if the logic ….
@lmacvittie #gluecon

20. Use
programmable
proxies to
implement
deployment
patterns that
require more
logic than basic
conditionals or
data from
external sources
DEVOPS
PATTERNS
@lmacvittie #gluecon
Canary Deployments
Blue/Green Deployments
A/B Testing
v.1
v.2
v.3
API Management
Redirection
Replication
(Dark Architecture)

21. If you can code
it, you can do it
(probably)
PROGRAMMABLE
PROXIES
More things you can do with a programmable proxy
Application
security
Broker
authentication
Identity
devices and
users
v1.04
API version
matching
Rate Limiting /
API quota
enforcement
@lmacvittie #gluecon

22. Programmability in the Network: Traffic Replication
Programmability in the Network: Canary Deployments
Programmability in the Network: Blue-Green Deployment Pattern
Devops.com - Code in Flight
Gluecon 2013 - Dark Architecture and How to Forklift Upgrade Your System
Dyn's CTO Cory von Wallenstein:
LineRate Proxy Download (https://linerate.f5.com/)
@lmacvittie #gluecon