feat: use of finely graded multi-stages

In preparation for a differentiated CI pipeline, the Dockerfile
can now be used with finer-grained multi-stages to build multi-
platform Docker images.

ubuntu:noble-20240904.1
|
`–[base]
   | - Ubuntu system package upgrades
   | - Ubuntu APT software management utils
   | - Ubuntu localization for 'en_US.UTF-8' and 'de_DE.UTF-8'
   | - TSN workspace user in '/home/tsn' ('UID=1005' and 'GID=205')
   | - Set main entry point to '/bin/bash'
   | - Switch to TSN workspace user in '/home/tsn'
   |
   `–[asdf-all]
     | - Ubuntu system packages for ASDF
     | - Install ASDF
     | - Install ASDF Plugin Manager
     | - Switch to TSN workspace user in '/home/tsn'
     |
     +–[asdf-amd64]
     | | - Empty, nothing to do.
   ,–:–´
   | |
   | +–[asdf-arm]
   | | | - Empty, nothing to do.
   +–:–´
   | |
   | +–[asdf-arm64]
   | | | - Empty, nothing to do.
   +–:–´
   | |
   | +–[asdf-riscv64]
   | | | - Empty, nothing to do.
   +–:–´
   | |
   | +–[asdf-ppc64le]
   | | | - Empty, nothing to do.
   +–:–´
   | |
   | `–[asdf-s390x]
   |   | - Empty, nothing to do.
   +–––´
   |
   `–[asdf]:
       - Verify ASDF, execute CLI.
       - Verify ASDF Plugin Manager, execute CLI.

Signed-off-by: Stephan Linz <[email protected]>

Dockerfile

@@ -26,7 +26,7 @@ FROM ubuntu:noble-20240904.1 AS base
 
 # overwrite Ubuntu default metadata
 LABEL mantainer="Stephan Linz <[email protected]>"
-LABEL version="2024.10.0"
+LABEL version="unstable"
 
 # ############################################################################
 
@@ -42,30 +42,13 @@ SHELL ["/bin/sh", "-ex", "-c"]
 
 # ############################################################################
 
-#
-# ASDF runtime version
-# https://asdf-vm.com/
-# https://github.com/asdf-vm/asdf/blob/master/CHANGELOG.md
-#
-
-# Define ASDF branch to be installed via git-clone
-ENV TSN_ASDF_BRANCH=v0.14.1
-
-#
-# ASDF Plugin Manager runtime version
-# https://github.com/asdf-community/asdf-plugin-manager
-# https://github.com/asdf-community/asdf-plugin-manager/blob/main/CHANGELOG.md
-#
-
-# Define ASDF Plugin Manager version to be installed via ASDF
-ENV TSN_ASDF_PM_VERSION=1.4.0
-
-# ############################################################################
-
 ENV DEBIAN_FRONTEND=noninteractive
 ENV DEBCONF_NONINTERACTIVE_SEEN=true
 ENV LANG=C.UTF-8
 
+# ############################################################################
+
+# switch to superuser
 USER root
 WORKDIR /
 
@@ -82,23 +65,23 @@ RUN apt-get --assume-yes update
 RUN apt-get --assume-yes dist-upgrade
 RUN apt-get --assume-yes install --no-install-recommends \
     apt-utils \
+    bash \
+    bash-completion \
     software-properties-common \
     vim
 RUN apt-get --assume-yes autoremove --purge
 RUN apt-get clean
 
-# Install requirements
-RUN apt-get --assume-yes install --no-install-recommends \
-    bash \
-    bash-completion \
-    bsdmainutils \
-    coreutils \
-    curl \
-    git-core \
-    grep \
-    sed
-RUN apt-get --assume-yes autoremove --purge
-RUN apt-get clean
+# ############################################################################
+
+# make /bin/sh symlink to bash instead of dash:
+RUN echo "dash dash/sh boolean false" | debconf-set-selections
+RUN dpkg-reconfigure --frontend=readline --priority=critical dash
+
+# HOTFIX: The construct above has no effect, do it manually!
+RUN ln -sf bash /bin/sh
+
+SHELL ["/bin/sh", "-exo", "pipefail", "-c"]
 
 # ############################################################################
 
@@ -120,25 +103,75 @@ RUN locale -a
 
 # ############################################################################
 
-# make /bin/sh symlink to bash instead of dash:
-RUN echo "dash dash/sh boolean false" | debconf-set-selections
-RUN dpkg-reconfigure --frontend=readline --priority=critical dash
+# Set executable for main entry point
+CMD ["/bin/bash"]
 
-# HOTFIX: The construct above has no effect, do it manually!
-RUN ln -sf bash /bin/sh
+# ############################################################################
 
-SHELL ["/bin/sh", "-exo", "pipefail", "-c"]
+# switch to workspace user
+USER $WSUSER_NAME
+WORKDIR $WSUSER_HOME
+
+# ############################################################################
+#
+# All architectures maintenance for ASDF and ASDF Plugin Manager
+#
+# ############################################################################
+
+FROM base AS asdf-all
 
 # ############################################################################
 
 #
-# Manage multiple runtime versions with the
-# ASDF version manager in workspace user space.
+# ASDF runtime version
+# https://asdf-vm.com/
+# https://github.com/asdf-vm/asdf/blob/master/CHANGELOG.md
+#
+
+# Define ASDF branch to be installed via git-clone
+ENV TSN_ASDF_BRANCH=v0.14.1
+
+#
+# ASDF Plugin Manager runtime version
+# https://github.com/asdf-community/asdf-plugin-manager
+# https://github.com/asdf-community/asdf-plugin-manager/blob/main/CHANGELOG.md
 #
 
+# Define ASDF Plugin Manager version to be installed via ASDF
+ENV TSN_ASDF_PM_VERSION=1.4.0
+
+# ############################################################################
+
+# switch to superuser
+USER root
+WORKDIR /
+
+# ############################################################################
+
+# Install requirements
+RUN apt-get --assume-yes install --no-install-recommends \
+    bsdmainutils \
+    coreutils \
+    curl \
+    git-core \
+    grep \
+    sed
+RUN apt-get --assume-yes autoremove --purge
+RUN apt-get clean
+
+# ############################################################################
+
+# switch to workspace user
 USER $WSUSER_NAME
 WORKDIR $WSUSER_HOME
 
+# ############################################################################
+
+#
+# Manage multiple runtime versions with the
+# ASDF version manager in workspace user space.
+#
+
 # Install ASDF
 RUN git clone https://github.com/asdf-vm/asdf.git ~/.asdf --depth 1 --branch $TSN_ASDF_BRANCH
 RUN echo ". ~/.asdf/asdf.sh" >> $WSUSER_HOME/.bashrc
@@ -182,65 +215,74 @@ RUN asdf-plugin-manager export > $WSUSER_HOME/.plugin-versions
 
 # ############################################################################
 #
-# AMD/x86 64-bit architecture maintenance
+# AMD/x86 64-bit architecture maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM base AS build-amd64
+FROM asdf-all AS asdf-amd64
 
 # ############################################################################
 #
-# ARMv7 32-bit architecture maintenance
+# ARMv7 32-bit architecture maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM base AS build-arm
+FROM asdf-all AS asdf-arm
 
 # ############################################################################
 #
-# ARMv8 64-bit architecture maintenance
+# ARMv8 64-bit architecture maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM base AS build-arm64
+FROM asdf-all AS asdf-arm64
 
 # ############################################################################
 #
-# RISC-V 64-bit architecture maintenance
+# RISC-V 64-bit architecture maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM base AS build-riscv64
+FROM asdf-all AS asdf-riscv64
 
 # ############################################################################
 #
-# IBM POWER8 architecture maintenance
+# IBM POWER8 architecture maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM base AS build-ppc64le
+FROM asdf-all AS asdf-ppc64le
 
 # ############################################################################
 #
-# IBM z-Systems architecture maintenance
+# IBM z-Systems architecture maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM base AS build-s390x
+FROM asdf-all AS asdf-s390x
 
 # ############################################################################
 #
-# All architectures maintenance
+# Final maintenance for ASDF and ASDF Plugin Manager
 #
 # ############################################################################
 
-FROM build-${TARGETARCH} AS build
+FROM asdf-${TARGETARCH} AS asdf
+
+# ############################################################################
+
+#
+# ASDF runtime version
+#
 
 RUN asdf version
 RUN asdf list
 
+# ############################################################################
+
+#
+# ASDF Plugin Manager runtime version
+#
+
 RUN asdf-plugin-manager version
 RUN asdf-plugin-manager list
-
-# Set executable for main entry point
-CMD ["/bin/bash"]