Block the installation of Debian's PHP packages

[tianon]

This will hopefully help folks with the confusion around installing packages like "php-apcu" and then wondering why they don't actually "work" (because they pull in Debian's PHP, and that's not what this image packages).

[tianon]

The suggested workaround for users who know what they're doing and are crazy enough to want two copies of PHP in their images would be to simply remove this file.

[tianon]

For Google's sake, here's what this looks like when a user tries to install something that doesn't make sense in this image:

root@212b2ae4fcdd:/# apt-get install php-apcu
Reading package lists... Done
Building dependency tree       
Reading state information... Done
Package php-apcu is not available, but is referred to by another package.
This may mean that the package is missing, has been obsoleted, or
is only available from another source

E: Package 'php-apcu' has no installation candidate

root@212b2ae4fcdd:/# apt-cache policy php-apcu
php-apcu:
  Installed: (none)
  Candidate: (none)
  Version table:
     5.1.8+4.0.11-1 -1
        500 http://deb.debian.org/debian stretch/main amd64 Packages

[PanMan]

This also prevents our php-imagick from installing, which worked before :(.

[tianon]

@PanMan it likely installed, but couldn't/shouldn't have been actually working with the proper PHP installation -- you likely got Debian's PHP instead, and simply didn't notice the swap

You want to install imagick from PECL instead: https://pecl.php.net/package/imagick

[mstenta]

I need to install phpunit and php5-geos in my image. What is the recommended approach to doing so now? GEOS was working for me before. Now it's causing build errors on Docker hub: farmOS/farmOS#49

[mstenta]

Let's focus discussion in this new issue: #551

[tianon]

See docker-library/docs#1111 for a documentation PR which explains the reasons for the change, the intended behavior, the workaround, and the proper fix.

[zerho]

The point for blocking the install is really clear but sorry what is not clear is the proper way that you suggest to install the different modules

[yosifkit]

@zerho, that depends on the extension that you need. We have a whole section in the Docker Hub docs that show different ways to install extensions: https://github.com/docker-library/docs/tree/5c5113376819629b6cc856de8ae1133e4c978bf0/php#how-to-install-more-php-extensions. Those use the scripts that we provide docker-php-ext-install, docker-php-ext-configure, and docker-php-ext-enable. You can see what is already enabled with php -m, and you can see the other core extensions available in the help output:

$ docker run -it --rm php:7.2 docker-php-ext-install
usage: /usr/local/bin/docker-php-ext-install [-jN] ext-name [ext-name ...]
   ie: /usr/local/bin/docker-php-ext-install gd mysqli
       /usr/local/bin/docker-php-ext-install pdo pdo_mysql
       /usr/local/bin/docker-php-ext-install -j5 gd mbstring mysqli pdo pdo_mysql shmop

if custom ./configure arguments are necessary, see docker-php-ext-configure

Possible values for ext-name:
bcmath bz2 calendar ctype curl dba dom enchant exif fileinfo filter ftp gd gettext gmp hash iconv imap interbase intl json ldap mbstring mysqli oci8 odbc opcache pcntl pdo pdo_dblib pdo_firebird pdo_mysql pdo_oci pdo_odbc pdo_pgsql pdo_sqlite pgsql phar posix pspell readline recode reflection session shmop simplexml snmp soap sockets sodium spl standard sysvmsg sysvsem sysvshm tidy tokenizer wddx xml xmlreader xmlrpc xmlwriter xsl zend_test zip

Some of the above modules are already compiled into PHP; please check
the output of "php -i" to see which modules are already loaded.

If you can live with the version of PHP in Debian or Ubuntu so that you can just install packages like php5-gd from apt, then you don't need the php image and can just build FROM the Debian or Ubuntu version of your choice.

[PeterBocan]

Yeah, the I'm currently trying to install "http" extension into the PHP and I am already 4 hours into this nightmare.

[wglambert]

@PeterBocan Here you go, you should add in specific versions for the packages

FROM php

RUN apt-get update; \
        apt-get install -y --no-install-recommends libssl-dev zlib1g-dev libcurl3-dev; \
        pecl install propro raphf; \
        docker-php-ext-enable propro raphf; \
        apt-get purge -y --auto-remove

RUN pecl install pecl_http; \
        docker-php-ext-enable http

$ docker build . -t php:test
Sending build context to Docker daemon  2.048kB
Step 1/3 : FROM php
 ---> df1b7c730f91
Step 2/3 : RUN apt-get update;  apt-get install -y --no-install-recommends libssl-dev zlib1g-dev libcurl3-dev;  pecl install propro raphf;      docker-php-ext-enable propro raphf;     apt-get purge -y --auto-remove
 ---> Using cache
 ---> 8431c5cdaec1
Step 3/3 : RUN pecl install pecl_http;  docker-php-ext-enable http
 ---> Using cache
 ---> 08796fc74ade
Successfully built 08796fc74ade
Successfully tagged php:test

$ docker run --rm php:test php -m | grep http 
http