Docker + PHP:8.1.1-FPM how to install imagick php extension?

Trying to install imagick for php 8.1.1.

On image of my Dockerfile below composer install gives the following error :

Installing dependencies from lock file (including require-dev)
Verifying lock file contents can be installed on current platform.
Your lock file does not contain a compatible set of packages. Please run composer update.

  Problem 1
    - Root composer.json requires PHP extension ext-imagick ^3.6 but it is missing from your system. Install or enable PHP's imagick extension.

To enable extensions, verify that they are enabled in your .ini files:
    - 
    - /usr/local/etc/php/conf.d/docker-php-ext-apcu.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-calendar.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-gd.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-intl.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-opcache.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-pdo_mysql.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-pdo_pgsql.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-sodium.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-xsl.ini
    - /usr/local/etc/php/conf.d/docker-php-ext-zip.ini

I tried various solutions

apt install php-imagick gives error:

Package php-imagick 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

apt install php8.1-imagick does not find any package

adding RUN docker-php-ext-install php-imagick or RUN docker-php-ext-install imagick at the end of my Dockerfile do not find any package

Dockerfile

FROM php:8.1.1-fpm

RUN apt-get clean && apt-get update \
    &&  apt-get install -y --no-install-recommends \
        locales \
        apt-utils \
        git \
        libicu-dev \
        g++ \
        libpng-dev \
        libxml2-dev \
        libzip-dev \
        libonig-dev \
        libxslt-dev \
        unzip \
        libpq-dev \
        nodejs \
        npm \
        wget \
        apt-transport-https \
        lsb-release \
        ca-certificates

RUN echo "en_US.UTF-8 UTF-8" > /etc/locale.gen  \
    &&  locale-gen

RUN curl -sS https://getcomposer.org/installer | php -- \
    &&  mv composer.phar /usr/local/bin/composer

RUN curl -sS https://get.symfony.com/cli/installer | bash \
    &&  mv /root/.symfony/bin/symfony /usr/local/bin

RUN docker-php-ext-configure \
            intl \
    &&  docker-php-ext-install \
            pdo pdo_mysql pdo_pgsql opcache intl zip calendar dom mbstring gd xsl

RUN pecl install apcu && docker-php-ext-enable apcu

RUN npm install --global yarn

WORKDIR /var/www/app/

RUN apt-get install -y libmagickwand-dev
RUN apt-get install -y imagemagick
RUN pecl install imagick

COPY ./app/composer.json ./
COPY ./app/composer.lock ./

To install the Imagick PHP Extension and lib we need to modify the Dockerfile.

An example of this is as follows, first we update the system sources and packages, then grab the required package for the PHP extension to run. afterwards we use pecl to install it then finally tell docker to enable it on the PHP Extensions list.

RUN apt-get update; \
    apt-get install -y libmagickwand-dev; \
    pecl install imagick; \
    docker-php-ext-enable imagick;

Sidenote: Incase you are new to bash and wondering why it doesn't have a bunch of RUN commands rather than just a singular command. the \ just chains them to the next line.