Search code examples
phpcloudsaas

How is the Twelve-Factor App manifesto applied to PHP projects?

I just read the Twelve-Factor App, which looks like a pretty comprehensive set of rules to apply in a web-based application. It uses python or rails in its examples, but never php... I was wondering which factors of the manifesto can be applied to PHP projects and how?

Thanks

Solution

  • Short answer:

    All points apply to PHP as the twelve factor app manifesto refers specifically for web apps.

    PHP has a very hard time complying to twelve factor, in particular in the items 2, 7, 8 9 (as a side effect of 7 and 8) and 12 (partially). Actually that's the first really grounded argument I have heard in the whole "PHP sucks" rant that is common on the Ruby and Python communities (don't get me wrong, I think Ruby and Python are better languages, but I don't hate PHP, and definitively hate the "my language is better" rants.)

    Being that said, it may be that your PHP project is not a web app or SaaS, but just a simple website, so you may just deem that twelve factor is not a need.

    Long answer: A point-by-point analysis would be:

    1. Codebase: not an issue

    2. Dependencies: the way PEAR works goes quite against this point, as pear dependencies are installed system wide and usually you don't have a consolidated manifesto to declare them. Is also usual for a PHP setup to require you to add packages to your OS installation to get some libraries available. Finally AFAIK there isn't a tool in PHP to provide isolation like "virtualenv", "rbenv" or "rvm" (or if it exists is not popular among the PHP community) Edit: Composer (http://getcomposer.org/) seems to do the right regarding dependencies, it still doesn't isolate the PHP version, but for all the rest it should be fine.

    3. Config: some PHP frameworks are not very well suited to do this, but there are certainly others that do well, so it's not a flaw of the platform itself

    4. Backing Services: shouldn't be much of an issue, despite maybe having to hack some frameworks a little in order to manage the services as resources

    5. Build, release, run: this is totally appliable to PHP as this definitively doesn't concern only "compiling". One may argue that several projects and hosting platforms on the PHP community abuse of direct FTP, etc. but that's not a flaw of PHP itself, and there is no real impediment on doing things right regarding this item.

    6. Processes: This definitively concerns to PHP. PHP is quite capable of running purely stateless processes (the emphasis is on the word stateless), and actually several frameworks make your life easy for it. For example, symfony provides out-of-the-box session management with memcached or database storage instead of regular sessions

    7. Port binding: Over simplyfing it, this point basically demands you to reverse proxy and have the actual webserver embedded on the app instead of being a separated component. This puts PHP in a very hard position to comply. Despite there are ways to do this (see the reply about using PHP as FastCGI) that's definitively not the most common nor the best supported way to serve a PHP app as it is on other communities (e.g. Ruby, Node.js).

    8. Processes: This is not impossible in PHP. However several elements put PHP in a hard position to comply. Namely the lack of good support for items 6 and 7; the fact that the PHP API to spawn new processes isn't really very nice to work with; and specially the way Apache's mod_php handles their workers (which is by far the most common deployment schema for PHP)

    9. Disposability: If you use the right tools there is nothing inherent on PHP to prevent you from creating fast, disposable, tidy web and worker processes. However I believe that since the underlying process model is hard to implement as per points 7 and 8, then 9 becomes a bit cumbersome as a side effect

    10. Dev/prod parity: This is very platform agnostic, and I would say one of the hardest to get done right. PHP is no exception to this rule, but it doesn't have a particular impediment either. Actually most of the tools named on the manifesto can be applied to a PHP project

    11. Logs: Having your app agnostic of the log system on the execution environment is totally doable on PHP

    12. Admin processes: The most important flaw of PHP regarding this point is its lack of a REPL shell. Regarding the rest, several frameworks like Symfony allow you to program admin tasks (e.g Doctine-based database migrations) and run them on the same environment as your "regular" web envionrment.

    Since the PHP community is evolving, it may be that it has already righted some of the wrongs mentioned.