Build mysql as shared extension for PHP 5.5 and 5.6

[thaJeztah]

Updated Dockerfiles for PHP 5.5 and 5.6 to build mysql as a shared extension and not enable it by default.
The mysql extension is deprecated since PHP 5.5 and using it is discouraged.

Users requiring the mysql extension can still enable it by adding extension=mysql.so to their php.ini, which should be added to the README because this breaks backwards compatibility with previous versions of this image.

closes #28

[yosifkit]

Sounds reasonable to me.

[tianon]

Is the ,/usr bit documented somewhere so we can read about why that's the correct value we should be using here? 😄

[md5]

It seems like it should be ,/usr/local.

[thaJeztah]

@tianon good question, think I picked it from the php internals book, but haven't checked what the best path would be there.

I think picking a path could be important because (if this gets merged), future extensions should probably set the same path as well.

[thaJeztah]

@md5 just checked; when building with ,/usr, the extension is put here;

/usr/local/lib/php/extensions/no-debug-non-zts-20131226/mysql.so

possibly, using the ,/usr is not even required, because php should use the globally defined 'extension-dir'. I will check what the result is when leaving it out and let you know.

[thaJeztah]

hm.. getting some gpg errors, first build;

gpg: directory `/root/.gnupg' created
gpg: new configuration file `/root/.gnupg/gpg.conf' created
gpg: WARNING: options in `/root/.gnupg/gpg.conf' are not yet active during this run
gpg: keyring `/root/.gnupg/secring.gpg' created
gpg: keyring `/root/.gnupg/pubring.gpg' created
gpg: requesting key 90D90EC1 from hkp server pgp.mit.edu
gpg: requesting key 7267B52D from hkp server pgp.mit.edu

then;

gpg --verify php.tar.bz2.asc
gpg: Signature made Thu Oct 16 08:17:09 2014 UTC using RSA key ID 90D90EC1
gpg: Good signature from "Julien Pauli <[email protected]>"
gpg: WARNING: This key is not certified with a trusted signature!
gpg:          There is no indication that the signature belongs to the owner.
Primary key fingerprint: 0BD7 8B5F 9750 0D45 0838  F95D FE85 7D9A 90D9 0EC1

Are these safe to ignore?

[tianon]

Yes, those are normal.

[thaJeztah]

Rebased the PR and removed the ,/usr.

Turns out that if the ,/usr is omitted, the global --extension-dir is used and the
shared extension is in the same location.

Just rebuilt the 5.6-apache Dockerfile to test after the rebase and afaics, it works correctly. (5.5-apache was tested before rebase)

PTAL, @tianon @yosifkit

[yosifkit]

LGTM

[thaJeztah]

Still needs the docs change in the README, perhaps this could be included in the changes you're working on wrt php.ini.

[tianon]

So, this should be covered now by just adding something like this to the Dockerfile of a project that needs mysql:

RUN docker-php-ext-install mysql

I know mysqli definitely works (see docker-library/wordpress#26).

[thaJeztah]

Yes, I've seen a lot of progress going on (sorry to be quiet a bit), quite a new approach. I haven't had the time yet to test the new system, but I think that will cover this.

I'll close the PR, thanks for an excellent job!