feat: Implement nix-based Dockerfile for CI (#7083)

.github/workflows/build-nix-image.yml

@@ -0,0 +1,101 @@
+name: Build Nix Docker image
+
+on:
+  push:
+    branches:
+      - develop
+    paths:
+      - ".github/workflows/build-nix-image.yml"
+      - "docker/nix.Dockerfile"
+      - "flake.nix"
+      - "flake.lock"
+      - "nix/**"
+  pull_request:
+    paths:
+      - ".github/workflows/build-nix-image.yml"
+      - "docker/nix.Dockerfile"
+      - "flake.nix"
+      - "flake.lock"
+      - "nix/**"
+  workflow_dispatch:
+
+concurrency:
+  group: ${{ github.workflow }}-${{ github.ref }}
+  cancel-in-progress: true
+
+defaults:
+  run:
+    shell: bash
+
+env:
+  UBUNTU_VERSION: "20.04"
+  RHEL_VERSION: "9"
+  DEBIAN_VERSION: "bookworm"
+
+jobs:
+  build:
+    name: Build and push Nix image (${{ matrix.distro }})
+    runs-on: ubuntu-latest
+    permissions:
+      contents: read
+      packages: write
+    strategy:
+      matrix:
+        include:
+          - distro: nixos
+          - distro: ubuntu
+          - distro: rhel
+          - distro: debian
+
+    steps:
+      - name: Checkout repository
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+
+      - name: Determine base image
+        id: vars
+        run: |
+          case "${{ matrix.distro }}" in
+            nixos)
+              echo "base_image=nixos/nix:latest" >> $GITHUB_OUTPUT
+              ;;
+            ubuntu)
+              echo "base_image=ubuntu:${UBUNTU_VERSION}" >> $GITHUB_OUTPUT
+              ;;
+            rhel)
+              echo "base_image=registry.access.redhat.com/ubi${RHEL_VERSION}/ubi:latest" >> $GITHUB_OUTPUT
+              ;;
+            debian)
+              echo "base_image=debian:${DEBIAN_VERSION}" >> $GITHUB_OUTPUT
+              ;;
+          esac
+
+      - name: Set up Docker Buildx
+        uses: docker/setup-buildx-action@4d04d5d9486b7bd6fa91e7baf45bbb4f8b9deedd # v4.0.0
+
+      - name: Login to GitHub Container Registry
+        if: github.event_name == 'push'
+        uses: docker/login-action@4907a6ddec9925e35a0a9e82d7399ccc52663121 # v4.1.0
+        with:
+          registry: ghcr.io
+          username: ${{ github.repository_owner }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+
+      - name: Docker metadata
+        id: meta
+        uses: docker/metadata-action@030e881283bb7a6894de51c315a6bfe6a94e05cf # v6.0.0
+        with:
+          images: ghcr.io/xrplf/ci/nix-${{ matrix.distro }}
+          tags: |
+            type=sha,prefix=sha-,format=short
+            type=raw,value=latest
+
+      - name: Build and push
+        uses: docker/build-push-action@bcafcacb16a39f128d818304e6c9c0c18556b85f # v7.1.0
+        with:
+          context: .
+          file: docker/nix.Dockerfile
+          platforms: linux/amd64
+          push: ${{ github.event_name == 'push' }}
+          tags: ${{ steps.meta.outputs.tags }}
+          labels: ${{ steps.meta.outputs.labels }}
+          build-args: BASE_IMAGE=${{ steps.vars.outputs.base_image }}