Evolving Archetecture

Evolving architecture make development easy and your site faster Leo Lapworth @ YAPC::EU 2007 http://leo.cuckoo.org/

Covering

Covering How running websites has evolved

Covering How running websites has evolved Servers improved

Covering How running websites has evolved Servers improved Architecture improved

Covering How running websites has evolved Servers improved Architecture improved Development tools improved

Covering How running websites has evolved Servers improved Architecture improved Development tools improved Code (and code libraries) got better

but not...

but not... Covering anything in depth

Concepts stolen from

Concepts stolen from Mod_perl guide

Concepts stolen from Mod_perl guide Léon Brocard

Concepts stolen from Mod_perl guide Léon Brocard Six Apart

Concepts stolen from Mod_perl guide Léon Brocard Six Apart Yahoo!

Concepts stolen from Mod_perl guide Léon Brocard Six Apart Yahoo! + many other people...

Concepts stolen from Mod_perl guide Léon Brocard Six Apart Yahoo! + many other people... ... this is social Perl

Templates

Templates An example of how things have improved...

Recognise this?

Recognise this? use CGI; $q = CGI->new(); $name = $q->param('name'); print $q->header('text/html'); $link = 'http://foo.com/'; print \"<html><head><title>HTML and code together</title></head><body>\"; print \"<a href=\\\"$link/$name\\\">\"; print \"Click here $name</a><br />\\n\"; print \"<table>\" . join(\"\\n\", map { \"<tr><td>$_</td></tr>\" } qw(this is hard to maintain)); print \"</table>\";

How about...

How about... Now, was it cellspacing, or cellpadding I need for ie4.02?

and...

and... I'm a developer, not a designer. I shouldn't have to know this £@$%!

Use templates...

Use templates... use Template;

Code, not HTML

Code, not HTML use CGI; use Template; $q = CGI->new(); print $q->header('text/html'); my %vals = ( name = $q->param('name'), ); $template = Template->new({ INCLUDE => '/path/' }); $template->process('hello.html',\\%vals);

I just code, I have clean code and I don't have to know HTML or browser compatibility issues

Simple changes make a huge difference

Servers

Single server

Single server Internet Web server (static & dynamic) All editing Database server

Lots of...

and... I thought I only changed one thing, but it's still broken

1 live server 1 development server

1 live server 1 development server Internet Live server Development server Web server Web server All editing (static & dynamic) (static & dynamic) Database server Database server

Does not solve: What did I change last? Who changed what / when?

You need...

Version control & docs

Version control & docs Use SVK with Subversion

Version control & docs Use SVK with Subversion Clkao - SVK

Version control & docs Use SVK with Subversion Use Trac (http://trac.edgewall.org) Clkao - SVK

Version control & docs Use SVK with Subversion Use Trac (http://trac.edgewall.org) - wiki Clkao - SVK

Version control & docs Use SVK with Subversion Use Trac (http://trac.edgewall.org) - wiki - task tracker Clkao - SVK

Version control & docs Use SVK with Subversion Use Trac (http://trac.edgewall.org) - wiki - task tracker - web interface to Subversion Clkao - SVK

Tests - all you need on one slide

Tests - all you need on one slide Write tests, write tests often

Tests - all you need on one slide Write tests, write tests often Run tests, run tests often

Tests - all you need on one slide Write tests, write tests often Run tests, run tests often Tests are good

Tests - all you need on one slide Write tests, write tests often Run tests, run tests often Tests are good Found a bug? - write the test that replicates it. You know it's ﬁxed when your test passes

Tests - all you need on one slide Write tests, write tests often Run tests, run tests often Tests are good Found a bug? - write the test that replicates it. You know it's ﬁxed when your test passes Use Test::More, and then test some more!

Making your site faster

mod_perl

mod_perl Code caching (loaded/compiled once)

mod_perl Code caching (loaded/compiled once) Server only spends time running the code

mod_perl Code caching (loaded/compiled once) Server only spends time running the code Apache::Registry for old/existing code

mod_perl Code caching (loaded/compiled once) Server only spends time running the code Apache::Registry for old/existing code Apache::SizeLimit (safety net)

mod_perl Code caching (loaded/compiled once) Server only spends time running the code Apache::Registry for old/existing code Apache::SizeLimit (safety net) Set it high

mod_perl Code caching (loaded/compiled once) Server only spends time running the code Apache::Registry for old/existing code Apache::SizeLimit (safety net) Set it high Check it

Front/back end split

Front/back end split Internet Slow Back end Front end (application server) Fast Web server Web server (static & proxy to (dynamic) application server) Database server Development server

or put another way...

or put another way... Internet slow and demanding kids (users)

or put another way... Canteen Internet Front end slow and Dinner-ladies - good at demanding serving precooked kids (static) food. Can order (users) from à la carte chefs and then serve

or put another way... Canteen Kitchen Internet Front end Back end slow and Dinner-ladies - good at Chefs - good at demanding serving precooked making à la carte kids (static) food. Can order (dynamic) food (users) from à la carte chefs and then serve

Internet Slow Back end Front end (application server) Fast Web server Web server (static & proxy to (dynamic) application server) Database server Development server

Speed up the frequent...

Speed up the frequent... Are you re-creating the same objects/data structures again and again?

Speed up the frequent... Are you re-creating the same objects/data structures again and again? Can this information persist for a period of time?

Add caching

Add caching Persisting data for a period of time

Add caching Persisting data for a period of time Simple to implement:

Add caching Persisting data for a period of time Simple to implement: Does cache exist?

Add caching Persisting data for a period of time Simple to implement: Does cache exist? YES -> retrieve it and return it

Add caching Persisting data for a period of time Simple to implement: Does cache exist? YES -> retrieve it and return it NO -> create data/object, store in cache and return it

Things you might cache

Things you might cache Search result sets (a list of ids)

Things you might cache Search result sets (a list of ids) Individual items

Things you might cache Search result sets (a list of ids) Individual items Look-ups of information from a database

Things you might cache Search result sets (a list of ids) Individual items Look-ups of information from a database Fetching of information from external sources

Centralise

Centralise Put caching methods in one package

Centralise Put caching methods in one package Put any generic methods in a package

We now have a cache Internet Slow Back end Front end (application server) Fast Web server Web server (static & proxy to Cache (dynamic) application server) Database server Development server

We now have a cache Internet Slow Back end Front end (application server) Fast Web server Web server (static & proxy to Cache Cache (dynamic) application server) Database server Development server

Adding in the cache...

Adding in the cache... Internet Kids

Adding in the cache... Internet Front end Kids Dinner-ladies

Adding in the cache... Internet Back end Front end Kids Chefs Dinner-ladies

Adding in the cache... Cache Internet Back end Front end Magic Kids Chefs Dinner-ladies freezer

Coping with more trafﬁc

Coping with more trafﬁc Development Internet Stage server server (in the ofﬁce) Front end Back end Web server (application server) Database (static & proxy server to application Web server server) (dynamic) Back end (application server) Web server (dynamic)

That's two separate disks

That's two separate disks Development Internet Stage server server (in the ofﬁce) Front end Back end Web server (application server) Database (static & proxy server to application Web server Cache server) (dynamic) Back end (application server) Web server Cache (dynamic)

Second kitchen, two freezers...

Second kitchen, two freezers... Internet Kids

Second kitchen, two freezers... Internet Front end Kids Dinner-ladies

Second kitchen, two freezers... Kitchen 1 Kitchen 2 Internet Front end Back end Kids Dinner-ladies Chefs

Second kitchen, two freezers... Kitchen 1 Kitchen 2 Internet Front end Back end Cache Kids Dinner-ladies Chefs Freezers

We want a cache across servers...

We want a cache across servers... Enter Memcache

We want a cache across servers... Enter Memcache See Léon Brocard's talk at 16:20 for the details

Development Internet Stage server server (in the ofﬁce) Front end Back end Web server (application server) Database (static & proxy server to application Web server server) (dynamic) Cache Back end (application server) Web server (dynamic)

Shared freezer

Shared freezer Internet Kids

Shared freezer Internet Front end Kids Dinner-ladies

Shared freezer Kitchen 1 Kitchen 2 Internet Front end Kids Dinner-ladies Back end Chefs

Shared freezer Kitchen 1 Kitchen 2 Internet Front end Kids Dinner-ladies Back end Cache Chefs Freezer

Maintaining servers

Maintaining servers Keep all servers identical where possible

Maintaining servers Keep all servers identical where possible Package your code (e.g. .debs)

Maintaining servers Keep all servers identical where possible Package your code (e.g. .debs) Centralise your crontabs and conﬁguration ﬁles (and put in version control)

Maintaining servers Keep all servers identical where possible Package your code (e.g. .debs) Centralise your crontabs and conﬁguration ﬁles (and put in version control) Deploy with one script: rsync + ssh + apt-get update & apt-get upgrade (or your OS equivalent) to each server

Simplify further Development Internet Stage server server (in the ofﬁce) Front end Back end Perlbal Web server load balancer / (static+dynamic) proxy Database Cache server Back end Web server (static+dynamic)

Waiters: cheaper, faster and less demanding

Waiters: cheaper, faster and less demanding Internet Kids

Waiters: cheaper, faster and less demanding Front end Internet Waiters - good at serving Kids quickly and dealing with annoying customers or Kitchens

Waiters: cheaper, faster and less demanding Kitchen 1 Kitchen 2 Front end Internet Waiters - good at serving Kids Back end quickly and dealing with annoying customers or Chefs - simple and complex meals (static and dynamic) Kitchens

Waiters: cheaper, faster and less demanding Kitchen 1 Kitchen 2 Front end Internet Waiters - good at serving Kids Back end quickly and dealing with Cache annoying customers or Chefs - simple and complex meals Freezer (static and dynamic) Kitchens

More tips for faster user experience

mod_gzip

mod_gzip HTML/css/xml

mod_gzip gzip HTML/css/xml

mod_gzip gzip HTML/css/xml Users

mod_gzip gzip HTML/css/xml Users If a browser support compressions... compress (javascript can be tricky - at least minify)

Cache headers (expiry)

Cache headers (expiry) Let web browsers know how long to cache

Cache somethings forever

Cache somethings forever /includes/js/<VERSION>/common.js

Cache somethings forever /includes/js/<VERSION>/common.js Ensures user has version which matches HTML (client could have cache of old HTML)

Cache somethings forever /includes/js/<VERSION>/common.js Ensures user has version which matches HTML (client could have cache of old HTML) Use include ﬁle to update all pages

Handling images: MogileFS

Handling images: MogileFS Store images by group (replication levels)

Handling images: MogileFS Store images by group (replication levels) Spread IO across disks & servers

Handling images: MogileFS Store images by group (replication levels) Spread IO across disks & servers Retrieve from fastest server

Handling images: MogileFS Store images by group (replication levels) Spread IO across disks & servers Retrieve from fastest server Integrate with Perlbal, hidden from the user

Handling images: MogileFS Store images by group (replication levels) Spread IO across disks & servers Retrieve from fastest server Integrate with Perlbal, hidden from the user Automatic resilience

Basic rules to consider

Basic rules to consider Centralise (code/templates/conﬁguration/ deployment etc)

Basic rules to consider Centralise (code/templates/conﬁguration/ deployment etc) Test, run lots of them

Basic rules to consider Centralise (code/templates/conﬁguration/ deployment etc) Test, run lots of them Cache if you need it; memcache is great

Basic rules to consider Centralise (code/templates/conﬁguration/ deployment etc) Test, run lots of them Cache if you need it; memcache is great Keep is simple (perlbal especially)

Basic rules to consider Centralise (code/templates/conﬁguration/ deployment etc) Test, run lots of them Cache if you need it; memcache is great Keep is simple (perlbal especially) Sometimes it's just easier to buy another server (this is not always true)

We covered...

We covered... perlbal

We covered... perlbal memcached

We covered... perlbal memcached svk (subversion)

We covered... perlbal memcached svk (subversion) trac

We covered... perlbal memcached svk (subversion) trac rsync

We covered... perlbal memcached svk (subversion) trac rsync gzip

We covered... perlbal mogileFS memcached svk (subversion) trac rsync gzip

We covered... perlbal mogileFS server architecture memcached svk (subversion) trac rsync gzip

We covered... perlbal mogileFS server architecture memcached Test::More svk (subversion) trac rsync gzip

We covered... perlbal mogileFS server architecture memcached Test::More svk (subversion) mod_perl trac rsync gzip

We covered... perlbal mogileFS server architecture memcached Test::More svk (subversion) mod_perl trac Template::Toolkit rsync gzip

We covered... perlbal mogileFS server architecture memcached Test::More svk (subversion) mod_perl trac Template::Toolkit rsync HTTP Cache headers gzip

We covered... perlbal mogileFS server architecture memcached Test::More svk (subversion) mod_perl trac Template::Toolkit rsync HTTP Cache headers gzip and...

...how a kitchen should run

...how a kitchen should run Any questions?

Evolving architecture http://leo.cuckoo.org/projects/ea/ Leo Lapworth http://leo.cuckoo.org/

Evolving Archetecture

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