How can I install the php memcached extension on Docker's PHP7 Alpine image?

Currently the php-memcached-dev:php7 branch contains the source for this extension.

To install it you can still use the docker-php-ext-* commands but you need to checkout the source yourself.

Base Installation

Assuming everything required to install the extension is already installed you can do:

RUN git clone -b php7 https://github.com/php-memcached-dev/php-memcached /usr/src/php/ext/memcached \    && docker-php-ext-configure /usr/src/php/ext/memcached \        --disable-memcached-sasl \    && docker-php-ext-install /usr/src/php/ext/memcached \    && rm -rf /usr/src/php/ext/memcached

This block will clone the repository, configure and install the extension then clean up after it self.

Pre-requisites

It is most likely that you need to install to packages to build the extension, we can add and remove them by doing:

ENV MEMCACHED_DEPS zlib-dev libmemcached-dev cyrus-sasl-dev gitRUN set -xe \    && apk add --no-cache libmemcached-libs zlib \    && apk add --no-cache \        --virtual .memcached-deps \        $MEMCACHED_DEPS \    && git clone -b php7 https://github.com/php-memcached-dev/php-memcached /usr/src/php/ext/memcached \    && docker-php-ext-configure /usr/src/php/ext/memcached \        --disable-memcached-sasl \    && docker-php-ext-install /usr/src/php/ext/memcached \    && rm -rf /usr/src/php/ext/memcached \    && apk del .memcached-deps

Update 17 May 2017

memcached has been added to the official pecl libraries for php7 now (v3 -> php7/7.1, v2 -> php5)

This makes installation a bit different

FROM php:7.0-alpineENV MEMCACHED_DEPS zlib-dev libmemcached-dev cyrus-sasl-devRUN apk add --no-cache --update libmemcached-libs zlibRUN set -xe \    && apk add --no-cache --update --virtual .phpize-deps $PHPIZE_DEPS \    && apk add --no-cache --update --virtual .memcached-deps $MEMCACHED_DEPS \    && pecl install memcached \    && echo "extension=memcached.so" > /usr/local/etc/php/conf.d/20_memcached.ini \    && rm -rf /usr/share/php7 \    && rm -rf /tmp/* \    && apk del .memcached-deps .phpize-deps

Try it.

FROM php:7.2.10-fpm-alpine3.7# Install PHP Extensions (igbinary & memcached)RUN apk add --no-cache --update libmemcached-libs zlibRUN set -xe && \    cd /tmp/ && \    apk add --no-cache --update --virtual .phpize-deps $PHPIZE_DEPS && \    apk add --no-cache --update --virtual .memcached-deps zlib-dev libmemcached-dev cyrus-sasl-dev && \# Install igbinary (memcached's deps)    pecl install igbinary && \# Install memcached    ( \        pecl install --nobuild memcached && \        cd "$(pecl config-get temp_dir)/memcached" && \        phpize && \        ./configure --enable-memcached-igbinary && \        make -j$(nproc) && \        make install && \        cd /tmp/ \    ) && \# Enable PHP extensions    docker-php-ext-enable igbinary memcached && \    rm -rf /tmp/* && \    apk del .memcached-deps .phpize-deps