How can I make this docker image smaller? - php

Question

I have the following dockerfile:
FROM php:7.2-apache
LABEL name "medico-app"
COPY composer.json composer.lock ./
COPY --from=composer:latest /usr/bin/composer /usr/bin/composer
RUN apt-get update && apt-get install -y --no-install-recommends git zip && composer install
COPY . /var/www/html
EXPOSE 80
When this image is built, it has a size of ~500 Mbs. I'm trying to compress this image to < 100 Mb so that I can use it on Zeit Now. According to what I'm reading in the docker documentation, multi-stage builds sometimes help in making images smaller. My current idea is to split the dockerfile into two stages, one where I would install the dependencies with compose and the other where I'd just have php and apache. I can't seem to get it right though. Any suggestions?
This is what I have so far:
# first stage
FROM composer:latest
COPY composer.json composer.lock ./
RUN composer install
For the second stage, I tried this
FROM httpd:2.4-alpine
LABEL name "medico-app"
COPY --from=0 /app/vendor ./vendor
COPY . /usr/local/apache2/htdocs/
EXPOSE 80
However when I run the container now, the php files aren't served, I just see them as text. Im probably missing something here with PHP/Apache.
EDIT:
I also tried this for the second stage but I can't get it to work:
FROM php:7.2-alpine
LABEL name "medico-app"
RUN apk --no-cache update && apk --no-cache add apache2 openrc
COPY --from=0 /app/vendor ./vendor
COPY . /var/www/
EXPOSE 80
Now when I open my localhost I don't see the PHP files that I should see. I just see the default it works page.

Answer 1

General tips for making docker images smaller:
Use a minimal base image such as the alpine versions. In this case you can use something like php:7.2-alpine and install apache using apk.
When using apt-get follow the best practices. In particular add && rm -rf /var/lib/apt/lists/*
Try minifiying the code being added to the image using something like gulp minify.