Symfony-live 2010, Paris. Conference review. Day 2

Here are my conclusions and thoughts about information that was presented on the Symfony-live 2010 conference.

All presentation from the conference can be found at http://www.symfony-project.org/blog/2010/02/17/symfony-live-day-1 and http://www.symfony-project.org/blog/2010/02/19/symfony-live-day-2.

OkAPI meet symfony, symfony meet OkAPI

I'm not sure what this presentation was about.

PHP Performance

Quite an interesting speech, describing some PHP and Zend Engine internals.

The interesting information is that all array_* and is_array function of PHP are not performance efficient. It is better to use your own implementation of them.

Git 101 Presentation

Nice presentation of Git.
The main conclusion is that we need to use Git. Reasons for it are:

• It is more reliable. Each Git setup (developer's PC, server etc.) has full information about the project i.e. history, modifications etc. So loosing any of the installations will not cause troubles for the whole project.
• Repository's size is slower.
• Updates are quicker.
• Logic different from SVN allows more flexible development.
  

For the first time we'll implement SVN-like logic but later will try to use all Git's features.

Using Zend Framework with Symfony
There are some nice examples of using parts of Zend Framework with Symfiny. Zend PDF and others are quite useful. Lucene search is nice but quite slow.

Implementing a Symfony Based CMS in a Publishing Company
Practical example of using Symfony for building custom site. There are no know-hows. It shows that we usually do everything the same way (correctly?) as they do.
Nice example of improving performance using several web servers and load balancer together with Master-Slave MySQL servers. We can use the same configuration on our projects when needed.

symfony live 2010 - Using symfony events to create clean class interfaces
Nice presentation on events dispatcher. There were some example on when and how Events should be used and when it should not. My opinion is that we should limit using of events and do it very carefully. The realization of the dispatcher is not ideal yet. Using events can make the code quite complicated to understand.

Symfony in the Cloud
Speech has covered all aspects of developing high load application on a cloud servers. They use the Amazon EC2 and S3 on http://nebul.us/ service.

Key issues when developing site in cloud environment are:

• Database connections - as soon as there are several MySQL databases (Master and Slave) we need to route all Select SQLs to Slave and all Update/Insert/Delete to Master. We need to track that the changes are successfully transferred from master to slave etc. Such requests routing can be done on the ORM level. Speaker showed example with Doctrene but we've already done it with Propel as well.
• File upload - as soon as there are several Apache servers there is no one place where user's files will originally get if we keep the default functionality. There is a chance that user can get to Server1, upload file and tomorrow he'll get to ServerN that will not have file stored on Server1. So we need to have one centralized file storage for the whole project. They've user Amazon S3. On the elastic hosting where all servers are within one network we can simply mount the main storage server to each Apache server's upload folder by NFS.
• Session storage - should be done by storing session in the database. It is well done in both PHP and Symfony so it is simple to change default session storage to MySQL session storage.
• Local development - as soon as by default scripts are configured to work on multi-server environment then there is a problems with local development when everything is done on one computer. Hopefully Symfony offers a lot of possibilities to create various environment for running scripts. It is quite simple to set up development environment with its own configuration
• Deploying - deploying the same code and DB changes to multiple servers is quite tricky. There should be proper procedures developed to do it.

Speaker has shown the good practices in running Symfony on multi-server environment. We can use them. But anyway each project requires its own specific configuration and procedures.

Debugging and Profiling Symfony Apps

Author's team has developed and maintain large site with 2m members, 14000 req/min running on 28 servers. On such sites performance is always an issue. But it is difficult to find the bottleneck in the system.

There are several ways suggested/used:

• Log analysis. Logs contain a lot of information. The problem is that logs from multiple servers should be stored in one place
• sfTimer. Allows measuring various operation times. But it requires some code modifications. It doesn't actually fits the prod server. It is more useful on the development stage.
• XHProf profiler. Helps to see Walltime and Memory Usage. Has web interface
• Tsung. Can benchmark HTTP, MySQL, Ejabber.
• Using graphite for visualizing data.

There is a lot of things to discover yet.

Building A Platform From Open Source At Yahoo

Presentation on how Yahoo use Symfony.

Presentation of Yahoo services. Ideas and techniques on making the scalable sites and performance optimization used on Yahoo.

From all Yahoo development tool we need to have a look at:

• YUI, that offers a lot of templates for common page and form elements.
• YQL. it is SQL-like query language for searching in internet.

The threats in using Yahoo tools is that as far as I know Yahoo is not in good financial condition this days and it can stop supporting tools to reduce expenses once.

Symfony 2.0 revealed

More details on Symfony 2 can be found at http://symfony-reloaded.org/

The main things are updated low-level architecture and usage of php 5.3 object oriented features (namespaces etc.).

There is no backward compatibility. It's not problem as soon as 1.3 - 1.4 are going to be supported for 3 more years.

My concern is the possibility to configure everything in Symfony. We liked symfony because it was well structured. There were rules that all developers working on Symfony should follow. It was simple then to understand code that someone has created and continue development. I hope Symfony developers will keep good default settings in Symfony 2.0 so that not many people will have to change it. Otherwise we'll have to work out our own development standards. We'll try to stick to symfony 1.4 experience as much as possible.

We need to keep in mind that Doctrene 2 will be included in Symfony and it will make huge step forward in developing on PHP.

We'll see what it is going to be at the and of 2010.

That's it for Day 2.