Initialise Github Workflows

.github/workflows/build.yml

@@ -0,0 +1,33 @@
+name: build
+run-name: Create patched ISO images
+
+on:
+  # allow the workflow to be called from another workflow
+  workflow_call:
+  # allow the workflow to be run from the Github Actions UI
+  workflow_dispatch:
+  # trigger the workflow when a 'push' event happens to any branch except the main branch
+  push:
+    branches:
+      - '**'
+      - '!main'
+
+jobs:
+  # the build job to run the build script
+  build:
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repository to the runner
+        uses: actions/checkout@v4
+      - name: Make the build script executable
+        run: chmod u+x scripts/build.sh
+      - name: Install dependent packages
+        run: sudo apt install -y p7zip-full p7zip-rar genisoimage fakeroot xorriso isolinux binutils squashfs-tools
+      - name: Run the build script
+        run: scripts/build.sh
+      # one set of upload statements for each OS image artifact
+      - name: Upload the vault-ubuntu-minimal artifact
+        uses: actions/upload-artifact@v4
+        with:
+          name: vault-ubuntu-minimal
+          path: vault-ubuntu-minimal.iso

.github/workflows/release.yml

@@ -0,0 +1,32 @@
+name: release
+run-name: Create a new release
+
+on:
+  # allow the workflow to be run from the Github Actions UI
+  workflow_dispatch:
+  # trigger the workflow run when a 'push' event happens to a tag with semantic versioning
+  push:
+    tags:
+      - "v*.*.*"
+
+jobs:
+  # call the build job (reuse from earlier workflow)
+  build:
+    uses: ./.github/workflows/build.yml
+  # the release job that will create a new release of all built OS images
+  release:
+    needs: build
+    runs-on: ubuntu-latest
+    steps:
+      - name: Check out the repository to the runner
+        uses: actions/checkout@v4
+      # one set of statements for each OS image that needs to be downloaded
+      # and included in the next release
+      - name: Download the vault-ubuntu-minimal artifact
+        uses: actions/download-artifact@v4
+        with:
+          name: vault-ubuntu-minimal
+      - name: Create a new release with latest images for all OSes
+        uses: softprops/action-gh-release@v2
+        with:
+          files: vault-ubuntu-minimal.iso

scripts/build.sh

@@ -0,0 +1,104 @@
+#! /bin/bash
+
+# function to detect the environment and return an appropriate file name
+assign_file_name () {
+    # check if it is a CI/CD environment like Github Actions
+    if [ -v CI ]; then
+        FILENAME="$1.iso"
+    else
+        IS_GIT=$(git rev-parse --is-inside-work-tree 2>&1)
+        # check if it is a git repository like when in local development
+        if [ $IS_GIT ]; then
+            GIT_COMMIT=$(git rev-parse --short HEAD)
+            DATE=$(date -u '+%Y%m%d')
+            FILENAME="$1-$DATE.$GIT_COMMIT.iso"
+        fi
+    fi
+    echo $FILENAME
+}
+
+# function to create builds for all linux operating systems in scope
+build_linux_oses () {
+    # array of URLs pointing to the base images of the operating system being handled
+    # give official, downloadable URLs, preferably from the same source as provided in the README
+    declare -a LINUXIMAGES=(
+        "https://releases.ubuntu.com/22.04.5/ubuntu-22.04.5-live-server-amd64.iso"
+    )
+
+    # array of directory names as present in this project
+    # this is used to copy and use the cloud-init config data
+    declare -a LINUXOSDIRS=(
+        "ubuntu-server-22-04-5"
+    )
+
+    # array of patched operating system names
+    # preferably in the `vault-<base-operating-system>` format
+    declare -a VAULTLINUXOSES=(
+        "vault-ubuntu-minimal"
+    )
+
+    # get lengths of above mentioned arrays
+    IMAGESLENGTH=${#LINUXIMAGES[@]}
+    OSESLENGTH=${#LINUXOSDIRS[@]}
+    VAULTSLENGTH=${#VAULTLINUXOSES[@]}
+
+    # perform a check to confirm that all arrays have equal lengths
+    # if not, exit with an appropriate message
+    if [ $IMAGESLENGTH -ne $OSESLENGTH ] || [ $OSESLENGTH -ne $VAULTLINUXOSES ] || [ $IMAGESLENGTH -ne $VAULTLINUXOSES ]; then
+        echo "IMAGESLENGTH, OSESLENGTH, VAULTLINUXOSES are not of equal lengths. Recheck array entries."
+        exit 1
+    fi
+
+    # iterate through the list of operating systems and patch them with data from the cloud-init config files
+    for (( i=0; i<${IMAGESLENGTH}; i++ ));
+    do
+        TARGETFILENAME=$(assign_file_name "${VAULTLINUXOSES[$i]}")
+        echo "Creating patched OS: $TARGETFILENAME..."
+        # download the base OS image
+        curl -X GET -OL ${LINUXIMAGES[$i]}
+        SOURCEISO=${LINUXIMAGES[$i]##*/}
+        # extract the downloaded ISO image to the iso/ directory
+        7z x -y $SOURCEISO -oiso
+
+        # copy the cloud-init configuration files into the iso/nocloud directory
+        mkdir -p iso/nocloud
+        cp "${LINUXOSDIRS[$i]}/meta-data" iso/nocloud/
+        cp "${LINUXOSDIRS[$i]}/user-data" iso/nocloud/
+
+        ## TODO: think of how this can possibly be extended to
+        ## other OSes. Do the boot kernel parameters change the
+        ## same way? Will we need a if-else tree to do it?
+
+        # modify boot related files
+        sed -i -e 's/---/ autoinstall  ---/g' iso/boot/grub/grub.cfg
+        sed -i -e 's/---/ autoinstall  ---/g' iso/boot/grub/loopback.cfg
+        # modify kernel boot parameters to insert path to cloud-init config
+        sed -i -e 's,---, ds=nocloud\\;s=/cdrom/nocloud/  ---,g'  iso/boot/grub/grub.cfg
+        sed -i -e 's,---, ds=nocloud\\;s=/cdrom/nocloud/  ---,g' iso/boot/grub/loopback.cfg
+
+        # create the final ISO image
+        xorriso -as mkisofs -r \
+            -V ${LINUXOSDIRS[$i]} \
+            -o $TARGETFILENAME \
+            -J \
+            -c '/boot.catalog' \
+            -b '/boot/grub/i386-pc/eltorito.img' \
+            -no-emul-boot -boot-load-size 4 -boot-info-table --grub2-boot-info \
+            -eltorito-alt-boot \
+            -isohybrid-gpt-basdat -isohybrid-apm-hfsplus \
+            iso/boot iso
+
+        FILESIZE=$(stat -c %s $TARGETFILENAME 2>&1)
+        # verify that the patched iso image file was created properly
+        if [[ $FILESIZE > 0 ]]; then
+            printf '%s (%d bytes) ... done!\n' $TARGETFILENAME $FILESIZE
+        else
+            printf 'Something went wrong while trying to build %s\n' $TARGETFILENAME
+        fi
+
+        # remove the iso/ directory
+        sudo rm -rf iso
+    done
+}
+
+build_linux_oses