Dockerfile throwing an error when using cURL

Question

I have a Dockerfile like this

FROM ubuntu:20.04

ENV DEBIAN_FRONTEND noninteractive

RUN apt-get update && \
    apt-get -y install \
        software-properties-common \
        vim \
        curl \
        sudo \
        dnsutils \
        telnet \
        git \
        wget \
        zip \
        unzip \
        unison \
        gawk \
        php7.4-cli \
        php7.4-mysql \
        php7.4-gd \
        php7.4-curl \
        php7.4-ldap \
        php7.4-xmlrpc \
        php7.4-xml \
        php7.4-mbstring \
        php7.4-zip \
        php7.4-mbstring \
        composer \
        subversion \
        openjdk-8-jdk \
        make ruby ruby-dev gcc && \
        apt-get clean && rm -rf /var/lib/apt/lists/*

# Composer install
ENV PATH "/composer/vendor/bin:$PATH"
ENV COMPOSER_ALLOW_SUPERUSER 1
ENV COMPOSER_HOME /composer
ENV COMPOSER_VERSION 1.4.2


RUN curl -s -f -L -o /tmp/installer.php https://raw.githubusercontent.com/composer/getcomposer.org/da290238de6d63faace0343efbdd5aa9354332c5/web/installer \
 && php -r " \
    \$signature = '669656bab3166a7aff8a7506b8cb2d1c292f042046c5a994c43155c0be6190fa0355160742ab2e1c88d40d5be660b410'; \
    \$hash = hash('SHA384', file_get_contents('/tmp/installer.php')); \
    if (\$signature != \$hash) { \
        unlink('/tmp/installer.php'); \
        echo 'Integrity check failed, installer is either corrupt or worse.' . PHP_EOL; \
        exit(1); \
    }" \
 && php /tmp/installer.php --no-ansi --install-dir=/usr/bin --filename=composer --version=${COMPOSER_VERSION} \
 && rm /tmp/installer.php \
 && composer --ansi --version --no-interaction


COPY ./asset/docker-entrypoint.sh /docker-entrypoint.sh

# Manage composer cache
RUN mkdir -p /composer && chmod -R 0777 /composer

# Manage certificate update manually
RUN sed '/DST_Root_CA_X3.crt/d' /etc/ca-certificates.conf > /tmp/cacerts.conf && mv /tmp/cacerts.conf /etc/ca-certificates.conf
RUN update-ca-certificates
RUN dpkg-reconfigure -f noninteractive ca-certificates

RUN chmod a+x /*.sh

WORKDIR /var/www/project

ENTRYPOINT ["/docker-entrypoint.sh"]
CMD ["/bin/bash"]

When I am running this file from Ubuntu terminal, I get the error below.

All settings correct for using Composer
SHA384 is not supported by your openssl extension

Even I tried to manually copy the installer.php and moved into path /tmp/installer.php, still I am getting the same error. I tried to change the composer version to 2.6.6, but there is no change in the error.

So can someone please let me know how can I solve this issue?

Answer 1

The core error is about your OpenSSL version during the build process:

SHA384 is not supported by your OpenSSL extension

Instead of going through this entire troublesome process of downloading the Composer and manual installing, I would make use of the Multi Stage Build feature. It would make your Dockerfile much cleaner.

Instead of:

FROM ubuntu:20.04

Mark it as the base build using newer syntax:

#syntax=docker/dockerfile:1.4

FROM ubuntu:20.04 as base

And instead of downloading and installing Composer by yourself, you can simply copy the binary from another image:

COPY --from=composer:2 --link /usr/bin/composer /usr/bin/composer