riotdocker-base: Split out build logic

This splits out all the build logic into the bash script build.sh. This
has two advantages:

- Only a single layer is added for this Dockerfile
    - This reduces overhead, especially with the VFS storage driver
    - Still takes full advantage of de-duplication of the layers
      concept: No image is based on intermediate steps anyway
- Improves maintainability
    - Strict split of meta data (--> Dockerfile) and build commands
      (--> build.sh)
    - No need for long `cmd_a && cmd_b && cmd_c && cmd_d` stuff anymore

riotdocker-base/Dockerfile

@@ -3,36 +3,11 @@ FROM ubuntu:jammy
 LABEL maintainer="Kaspar Schleiser <[email protected]>"
 
 RUN \
-    echo 'Update the package index files to latest available versions' >&2 && \
-    apt-get update && \
-    echo 'Install GCC' >&2 && \
-    apt-get -y --no-install-recommends install \
-        gcc \
-        git \
-        python3 \
-        python3-dev \
-        python3-pip \
-        && \
-    echo 'Clean up installation files' >&2 && \
-    apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+    --mount=type=bind,source=build.sh,target=/root/build.sh \
+    --mount=type=bind,source=run.sh,target=/root/run.sh \
+    --mount=type=bind,source=create_user.c,target=/root/create_user.c \
+    cd /root && ./build.sh
 
-# compile suid create_user binary
-COPY create_user.c /tmp/create_user.c
-RUN gcc -DHOMEDIR=\"/data/riotbuild\" -DUSERNAME=\"riotbuild\" /tmp/create_user.c -o /usr/local/bin/create_user \
-    && chown root:root /usr/local/bin/create_user \
-    && chmod u=rws,g=x,o=- /usr/local/bin/create_user \
-    && rm /tmp/create_user.c
-
-# Create working directory for mounting the RIOT sources
-RUN mkdir -m 777 -p /data/riotbuild
-
-# Set a global system-wide git user and email address
-RUN git config --system user.name "riot" && \
-    git config --system user.email "[email protected]" && \
-    git config --system --add safe.directory /data/riotbuild
-
-# Copy our entry point script (signal wrapper)
-COPY run.sh /run.sh
 ENTRYPOINT ["/bin/bash", "/run.sh"]
 
 # By default, run a shell when no command is specified on the docker command line

riotdocker-base/build.sh

@@ -0,0 +1,83 @@
+#!/bin/bash
+
+# Automatically exit on error
+set -e
+
+COUNTER_STEP=0
+COUNTER_SUBSTEP=0
+BLUE="\e[34m"
+BOLD="\e[1m"
+NORMAL="\e[0m"
+
+step() {
+    COUNTER_SUBSTEP=0
+    COUNTER_STEP=$(("$COUNTER_STEP" + 1))
+    printf "${BLUE}${BOLD}==>${NORMAL}${BOLD} Step %d:${NORMAL} %s\n" "$COUNTER_STEP" "$1"
+}
+
+substep() {
+    COUNTER_SUBSTEP=$(("$COUNTER_SUBSTEP" + 1))
+    printf "${BLUE}${BOLD}    -->${NORMAL}${BOLD} Step %d.%d:${NORMAL} %s\n" \
+        "$COUNTER_STEP" "$COUNTER_SUBSTEP" "$1"
+}
+
+step_install_dev_tools() {
+    step "Installing development tools"
+
+    substep "Updating package index"
+    apt-get update
+
+    substep "Installing GCC"
+    apt-get -y --no-install-recommends install gcc
+
+    substep "Installing git"
+    apt-get -y --no-install-recommends install git
+
+    substep "Installing Python"
+    apt-get -y --no-install-recommends install \
+        python3 \
+        python3-dev \
+        python3-pip
+
+    substep "Clean up installation files"
+    apt-get clean
+    rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
+}
+
+step_provide_create_user_cmd() {
+    step "Providing create_user binary"
+
+    substep "Compiling create_user from source"
+    gcc -DHOMEDIR=\"/data/riotbuild\" -DUSERNAME=\"riotbuild\" create_user.c -o /usr/local/bin/create_user
+
+    substep "Updating file attributes of create_user"
+    chown root:root /usr/local/bin/create_user
+    chmod u=rws,g=x,o=- /usr/local/bin/create_user
+}
+
+step_setup_dirs() {
+    step "Setting up folders and files"
+
+    substep "Creating /data/riotbuild"
+    mkdir -m 777 -p /data/riotbuild
+
+    substep "Creating /run.sh"
+    cp run.sh /run.sh
+}
+
+step_setup_git() {
+    step "Setting up git"
+
+    substep "Configuring user and email"
+    git config --system user.name "riot"
+    git config --system user.email "[email protected]"
+
+    substep "Setting up safe directories"
+    git config --system --add safe.directory /data/riotbuild
+}
+
+step_install_dev_tools
+step_provide_create_user_cmd
+step_setup_dirs
+step_setup_git
+exit 0