containerize: pin the Spack version used in a container (#21910)

This PR permits to specify the `url` and `ref` of the Spack instance used in a container recipe simply by expanding the YAML schema as outlined in #20442:
```yaml
container:
  images:
    os: amazonlinux:2
    spack:
      ref: develop
      resolve_sha: true
```
The `resolve_sha` option, if true, verifies the `ref` by cloning the Spack repository in a temporary directory and transforming any tag or branch name to a commit sha. When this new ability is leveraged an additional "bootstrap" stage is added, which builds an image with Spack setup and ready to install software. The Spack repository to be used can be customized with the `url` keyword under `spack`.

Modifications:
- [x] Permit to pin the version of Spack, either by branch or tag or sha
- [x] Added a few new OSes (centos:8, amazonlinux:2, ubuntu:20.04, alpine:3, cuda:11.2.1)
- [x] Permit to print the bootstrap image as a standalone
- [x] Add documentation on the new part of the schema
- [x] Add unit tests for different use cases

share/spack/templates/container/Dockerfile

@@ -1,3 +1,8 @@
+{% if render_phase.bootstrap %}
+{{ bootstrap.recipe }}
+
+{% endif %}
+{% if render_phase.build %}
 # Build stage with Spack pre-installed and ready to be used
 FROM {{ build.image }} as builder
 
@@ -35,7 +40,8 @@ RUN cd {{ paths.environment }} && \
 {% if extra_instructions.build %}
 {{ extra_instructions.build }}
 {% endif %}
-
+{% endif %}
+{% if render_phase.final %}
 # Bare OS image to run the installed executables
 FROM {{ run.image }}
 
@@ -49,12 +55,12 @@ RUN {% if os_package_update %}{{ os_packages_final.update }} \
  && {% endif %}{{ os_packages_final.install }} {{ os_packages_final.list | join | replace('\n', ' ') }} \
  && {{ os_packages_final.clean }}
 {% endif %}
-
 {% if extra_instructions.final %}
+
 {{ extra_instructions.final }}
 {% endif %}
 {% for label, value in labels.items() %}
 LABEL "{{ label }}"="{{ value }}"
 {% endfor %}
-
 ENTRYPOINT ["/bin/bash", "--rcfile", "/etc/profile", "-l"]
+{% endif %}

share/spack/templates/container/alpine_3.dockerfile

@@ -0,0 +1,7 @@
+{% extends "container/bootstrap-base.dockerfile" %}
+{% block install_os_packages %}
+RUN apk update \
+ && apk add --no-cache curl findutils gcc g++ gfortran git gnupg \
+        make patch python3 py3-pip tcl unzip bash \
+ && pip3 install boto3
+{% endblock %}

share/spack/templates/container/amazonlinux_2.dockerfile

@@ -0,0 +1,24 @@
+{% extends "container/bootstrap-base.dockerfile" %}
+{% block install_os_packages %}
+RUN yum update -y \
+ && yum groupinstall -y "Development Tools" \
+ && yum install -y \
+        curl \
+        findutils \
+        gcc-c++ \
+        gcc \
+        gcc-gfortran \
+        git \
+        gnupg2 \
+        hostname \
+        iproute \
+        make \
+        patch \
+        python \
+        python-pip \
+        python-setuptools \
+        unzip \
+ && pip install boto3 \
+ && rm -rf /var/cache/yum \
+ && yum clean all
+{% endblock %}

share/spack/templates/container/bootstrap-base.dockerfile

@@ -0,0 +1,45 @@
+FROM {{ bootstrap.image }} as bootstrap
+
+{% block env_vars %}
+ENV SPACK_ROOT=/opt/spack \
+    CURRENTLY_BUILDING_DOCKER_IMAGE=1 \
+    container=docker
+{% endblock %}
+
+{% block install_os_packages %}
+{% endblock %}
+
+RUN mkdir $SPACK_ROOT && cd $SPACK_ROOT && \
+    {{ bootstrap.spack_checkout }} && \
+    mkdir -p $SPACK_ROOT/opt/spack
+
+RUN ln -s $SPACK_ROOT/share/spack/docker/entrypoint.bash \
+          /usr/local/bin/docker-shell \
+ && ln -s $SPACK_ROOT/share/spack/docker/entrypoint.bash \
+          /usr/local/bin/interactive-shell \
+ && ln -s $SPACK_ROOT/share/spack/docker/entrypoint.bash \
+          /usr/local/bin/spack-env
+
+RUN mkdir -p /root/.spack \
+ && cp $SPACK_ROOT/share/spack/docker/modules.yaml \
+        /root/.spack/modules.yaml \
+ && rm -rf /root/*.* /run/nologin $SPACK_ROOT/.git
+
+# [WORKAROUND]
+# https://superuser.com/questions/1241548/
+#     xubuntu-16-04-ttyname-failed-inappropriate-ioctl-for-device#1253889
+RUN [ -f ~/.profile ]                                               \
+ && sed -i 's/mesg n/( tty -s \\&\\& mesg n || true )/g' ~/.profile \
+ || true
+
+{% block post_checkout %}
+{% endblock %}
+
+WORKDIR /root
+SHELL ["docker-shell"]
+
+# Creates the package cache
+RUN spack spec hdf5+mpi
+
+ENTRYPOINT ["/bin/bash", "/opt/spack/share/spack/docker/entrypoint.bash"]
+CMD ["interactive-shell"]

share/spack/templates/container/centos_7.dockerfile

@@ -0,0 +1,26 @@
+{% extends "container/bootstrap-base.dockerfile" %}
+{% block install_os_packages %}
+RUN yum update -y \
+ && yum install -y epel-release \
+ && yum update -y \
+ && yum --enablerepo epel groupinstall -y "Development Tools" \
+ && yum --enablerepo epel install -y \
+        curl \
+        findutils \
+        gcc-c++ \
+        gcc \
+        gcc-gfortran \
+        git \
+        gnupg2 \
+        hostname \
+        iproute \
+        make \
+        patch \
+        python \
+        python-pip \
+        python-setuptools \
+        unzip \
+ && pip install boto3 \
+ && rm -rf /var/cache/yum \
+ && yum clean all
+{% endblock %}

share/spack/templates/container/centos_8.dockerfile

@@ -0,0 +1,29 @@
+{% extends "container/bootstrap-base.dockerfile" %}
+{% block install_os_packages %}
+RUN yum update -y \
+ # See https://fedoraproject.org/wiki/EPEL#Quickstart for powertools
+ && yum install -y dnf-plugins-core \
+ && dnf config-manager --set-enabled powertools \
+ && yum install -y epel-release \
+ && yum update -y \
+ && yum --enablerepo epel groupinstall -y "Development Tools" \
+ && yum --enablerepo epel install -y \
+        curl \
+        findutils \
+        gcc-c++ \
+        gcc \
+        gcc-gfortran \
+        git \
+        gnupg2 \
+        hostname \
+        iproute \
+        make \
+        patch \
+        python38 \
+        python38-pip \
+        python38-setuptools \
+        unzip \
+ && pip3 install boto3 \
+ && rm -rf /var/cache/yum \
+ && yum clean all
+{% endblock %}

share/spack/templates/container/cuda_11_2_1.dockerfile

@@ -0,0 +1 @@
+ubuntu_2004.dockerfile

share/spack/templates/container/ubuntu_1604.dockerfile

@@ -0,0 +1,32 @@
+{% extends "container/bootstrap-base.dockerfile" %}
+{% block env_vars %}
+{{ super() }}
+ENV DEBIAN_FRONTEND=noninteractive   \
+    LANGUAGE=en_US.UTF-8 \
+    LANG=en_US.UTF-8 \
+    LC_ALL=en_US.UTF-8
+{% endblock %}
+{% block install_os_packages %}
+RUN apt-get -yqq update \
+ && apt-get -yqq install --no-install-recommends \
+        build-essential \
+        ca-certificates \
+        curl \
+        file \
+        g++ \
+        gcc \
+        gfortran \
+        git \
+        gnupg2 \
+        iproute2 \
+        locales \
+        lua-posix \
+        make \
+        python3 \
+        python3-pip \
+        python3-setuptools \
+        unzip \
+ && locale-gen en_US.UTF-8 \
+ && pip3 install boto3 \
+ && rm -rf /var/lib/apt/lists/*
+{% endblock %}

share/spack/templates/container/ubuntu_1804.dockerfile

@@ -0,0 +1,6 @@
+{% extends "container/ubuntu_1604.dockerfile" %}
+{% block post_checkout %}
+# [WORKAROUND]
+# https://bugs.launchpad.net/ubuntu/+source/lua-posix/+bug/1752082
+RUN ln -s posix_c.so /usr/lib/x86_64-linux-gnu/lua/5.2/posix.so
+{% endblock %}

share/spack/templates/container/ubuntu_2004.dockerfile

@@ -0,0 +1 @@
+ubuntu_1604.dockerfile