Add GitHub workflow to build & publish container to ghcr.io

Author: PhrozenByte

.github/workflows/container-publish.yml

@@ -0,0 +1,66 @@
+name: Build & publish container
+
+on:
+  push:
+    branches: [ main ]
+  workflow_dispatch: {}
+
+concurrency: build
+
+env:
+  CI_TOOLS_SETUP: https://raw.githubusercontent.com/SGSGermany/ci-tools/main/setup.sh
+
+defaults:
+  run:
+    shell: bash -eu -o pipefail {0}
+
+jobs:
+  build:
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+
+    env:
+      REGISTRY: ghcr.io
+      OWNER: sgsgermany
+      IMAGE: butane
+
+    steps:
+      - name: Setup CI tools
+        run: |
+          . <(curl -fsS -L "$CI_TOOLS_SETUP" | bash -s ~/ci-tools)
+          echo "CI_TOOLS=$CI_TOOLS" | tee -a "$GITHUB_ENV"
+          echo "CI_TOOLS_PATH=$CI_TOOLS_PATH" | tee -a "$GITHUB_ENV"
+
+      - name: Checkout repository
+        uses: actions/checkout@v4
+
+      - name: Log into container registry ${{ env.REGISTRY }}
+        uses: redhat-actions/podman-login@v1
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Generate container image tags
+        run: |
+          source <(./tags.sh "$GITHUB_RUN_ID.$GITHUB_RUN_NUMBER")
+          echo "MILESTONE=$MILESTONE" | tee -a "$GITHUB_ENV"
+          echo "VERSION=$VERSION" | tee -a "$GITHUB_ENV"
+          echo "TAGS=$TAGS" | tee -a "$GITHUB_ENV"
+
+      - name: Build container image
+        run: |
+          buildah unshare ./build.sh
+
+      - name: Container image metadata
+        run: |
+          podman image inspect "localhost/$IMAGE:${TAGS%% *}"
+
+      - name: Push container image
+        uses: redhat-actions/push-to-registry@v2
+        with:
+          image: ${{ env.IMAGE }}
+          registry: ${{ env.REGISTRY }}/${{ env.OWNER }}
+          tags: ${{ env.TAGS }}

container.env

@@ -1,7 +1,7 @@
-REGISTRY="ghcr.io"
-OWNER="sgsgermany"
-IMAGE="butane"
-TAGS="latest"
+REGISTRY="${REGISTRY:-ghcr.io}"
+OWNER="${OWNER:-sgsgermany}"
+IMAGE="${IMAGE:-butane}"
+TAGS="${TAGS:-latest}"
 
 BUTANE_GIT_REPO="https://github.com/coreos/butane"
 BUTANE_BINARY_URL="$BUTANE_GIT_REPO/releases/latest/download/butane-x86_64-unknown-linux-gnu"

tags.sh

@@ -0,0 +1,62 @@
+#!/bin/bash
+# Unbound
+# A container running Butane, a config translator for FCOS' Ignition.
+#
+# Copyright (c) 2025  SGS Serious Gaming & Simulations GmbH
+#
+# This work is licensed under the terms of the MIT license.
+# For a copy, see LICENSE file or <https://opensource.org/licenses/MIT>.
+#
+# SPDX-License-Identifier: MIT
+# License-Filename: LICENSE
+
+set -eu -o pipefail
+export LC_ALL=C.UTF-8
+
+[ -v CI_TOOLS ] && [ "$CI_TOOLS" == "SGSGermany" ] \
+    || { echo "Invalid build environment: Environment variable 'CI_TOOLS' not set or invalid" >&2; exit 1; }
+
+[ -v CI_TOOLS_PATH ] && [ -d "$CI_TOOLS_PATH" ] \
+    || { echo "Invalid build environment: Environment variable 'CI_TOOLS_PATH' not set or invalid" >&2; exit 1; }
+
+source "$CI_TOOLS_PATH/helper/common.sh.inc"
+source "$CI_TOOLS_PATH/helper/github.sh.inc"
+
+BUILD_DIR="$(CDPATH= cd -- "$(dirname -- "${BASH_SOURCE[0]}")" && pwd -P)"
+source "$BUILD_DIR/container.env"
+
+BUILD_INFO=""
+if [ $# -gt 0 ] && [[ "$1" =~ ^[a-zA-Z0-9_.-]+$ ]]; then
+    BUILD_INFO=".${1,,}"
+fi
+
+# get latest Butane version
+GITHUB_REPO_IDENT="${BUTANE_GIT_REPO#https://github.com/}"
+VERSION="$(github_latest "$GITHUB_REPO_IDENT")"
+
+if [ -z "$VERSION" ]; then
+    echo "Unable to read Butane version from GitHub API" >&2
+    exit 1
+elif ! [[ "$VERSION" =~ ^v([0-9]+)\.([0-9]+)\.([0-9]+)([+~-]|$) ]]; then
+    echo "Unable to read Butane version from GitHub API: '$VERSION' is no valid version" >&2
+    exit 1
+fi
+
+VERSION_FULL="${VERSION:1}"
+VERSION="${BASH_REMATCH[1]}.${BASH_REMATCH[2]}.${BASH_REMATCH[3]}"
+VERSION_MINOR="${BASH_REMATCH[1]}.${BASH_REMATCH[2]}"
+VERSION_MAJOR="${BASH_REMATCH[1]}"
+
+# build tags
+BUILD_INFO="$(date --utc +'%Y%m%d')$BUILD_INFO"
+
+TAGS=(
+    "v$VERSION" "v$VERSION-$BUILD_INFO"
+    "v$VERSION_MINOR" "v$VERSION_MINOR-$BUILD_INFO"
+    "v$VERSION_MAJOR" "v$VERSION_MAJOR-$BUILD_INFO"
+    "latest"
+)
+
+printf 'MILESTONE="%s"\n' "$VERSION_MINOR"
+printf 'VERSION="%s"\n' "$VERSION_FULL"
+printf 'TAGS="%s"\n' "${TAGS[*]}"