Php: Add redis to installable extensions

[wernight]

Related to #262, I often want to install the very popular Redis client for PHP. This isn't trivial on Alpine Linux. If you could please support it, it'd help greatly.

[wernight]

Steps:

$ apk add --update --no-cache autoconf g++ make
$ pecl install redis
$ docker-php-ext-enable redis

[shouze]

Hi @wernight redis is not shipped within php source code so, you should just follow explained steps in https://github.com/docker-library/php/issues/262#issuecomment-233108680.

[wernight]

Could there be a place for people to include ways to install common extensions, or some docker-php-ext-install run a script that does the install?

[tianon]

See https://github.com/docker-library/php/issues/75#issuecomment-353673374, which describes how I determine what's necessary to install extensions (and really compiled software in general).

Given that redis is not a built-in extension (as noted above), there's nothing for us to do here. Installing redis from PECL _is_ the appropriate solution. :+1:

[vladkras]

apk add --update --no-cache autoconf g++ make
adds extra 200Mb to the 179Mb alpine package so I prefere to install it from source

ENV REDIS_VERSION 4.0.2

RUN curl -L -o /tmp/redis.tar.gz https://github.com/phpredis/phpredis/archive/$REDIS_VERSION.tar.gz \
    && tar xfz /tmp/redis.tar.gz \
    && rm -r /tmp/redis.tar.gz \
    && mkdir -p /usr/src/php/ext \
    && mv phpredis-* /usr/src/php/ext/redis

RUN docker-php-ext-install redis

(last command purges all runtime packages after installation)
inspired by #77