ci: restore dependency-storing dockerfile

.github/workflows/ci.yml

@@ -3,51 +3,85 @@ name: CI
 on:
   push:
     branches: [ "main" ]
+    tags: [ '*' ]
+    paths-ignore: [ '*.md' ]
   pull_request:
     branches: [ "main" ]
 
 env:
   CARGO_TERM_COLOR: always
+  REGISTRY: ghcr.io
+  IMAGE_NAME: ${{ github.repository }}
+  UBUNTU_DOCKERFILE: .github/workflows/ubuntu.dockerfile
+
+permissions:
+  pull-requests: read
+  contents: read
+  packages: read
 
 jobs:
-  ci:
+  set-vars:
     runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v5
+        with:
+          fetch-depth: 2
+          sparse-checkout: |
+            .github
+            Cargo.toml
+          sparse-checkout-cone-mode: false
+      - id: set-vars
+        run: ./.github/workflows/set-vars.sh ${GITHUB_REPOSITORY@L}
+    outputs:
+      msrv: ${{ steps.set-vars.outputs.msrv }}
+      should-build: ${{ steps.set-vars.outputs.should_build == 'true' && github.event_name == 'push' }}
+      container-path: ${{ steps.set-vars.outputs.container_path }}
+
+  container-build:
+    runs-on: ubuntu-latest
+    needs: set-vars
+    if: ${{ needs.set-vars.outputs.should-build == 'true' }}
     permissions:
-      contents: read
-      packages: read
+      packages: write
+      id-token: write
 
     steps:
-      - uses: actions/checkout@v4
-      - name: Get MSRV
-        id: msrv
-        run: |
-          echo "msrv=$(
-          awk '/^rust-version = "[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+"$/ {
-            print substr($NF, 2, length($NF) - 2)
-          }' Cargo.toml)" >> "$GITHUB_OUTPUT"
-      - name: Set XDG_RUNTIME_DIR
-        id: xrd
-        run: echo "testdir=$PWD/test-xwls" >> "$GITHUB_OUTPUT"
-      - name: Install dependencies
-        run: |
-          sudo apt-get update
-          sudo apt-get install -y xwayland clang libxcb1 libxcb-cursor0 libxcb-cursor-dev pkg-config libegl1
-        env:
-          DEBIAN_FRONTEND: noninteractive
+      - uses: docker/setup-buildx-action@v3
+      - uses: docker/login-action@v3
+        with:
+          registry: ${{ env.REGISTRY }}
+          username: ${{ github.actor }}
+          password: ${{ secrets.GITHUB_TOKEN }}
+      - uses: docker/build-push-action@v6
+        with:
+          file: ${{ env.UBUNTU_DOCKERFILE }}
+          push: true
+          tags: ${{ needs.set-vars.outputs.container-path }}-ubuntu:latest
+          labels: org.opencontainers.image.source=${{ github.server_url }}/${{ github.repository }}
+          cache-from: type=gha
+          cache-to: type=gha,mode=max
+
+  xwls-build-test:
+    needs: [container-build, set-vars]
+    if: ${{ always() && (needs.container-build.result == 'success' || needs.container-build.result == 'skipped') }}
+    runs-on: ubuntu-latest
+    container:
+      image: ${{ needs.set-vars.outputs.container-path }}-ubuntu:latest
+      credentials:
+        username: ${{ github.actor }}
+        password: ${{ secrets.GITHUB_TOKEN }}
+
+    steps:
+      - uses: actions/checkout@v5
       - uses: dtolnay/rust-toolchain@master
         with:
-          toolchain: ${{ steps.msrv.outputs.msrv }}
+          toolchain: ${{ needs.set-vars.outputs.msrv }}
           components: clippy, rustfmt
-      - uses: Swatinem/rust-cache@v2
       - name: Build
         run: cargo build --all-targets --profile ci --locked --verbose
       - name: Run tests
-        run: |
-          mkdir "$XDG_RUNTIME_DIR"
-          cargo test --profile ci --locked --verbose -- --test-threads 1 --nocapture
-        env:
-          XDG_RUNTIME_DIR: ${{ steps.xrd.outputs.testdir }}
+        run: cargo test --profile ci --locked --verbose -- --test-threads 1 --nocapture
       - name: Format check
         run: cargo fmt --check
       - name: Clippy
-        run: cargo clippy --profile ci --locked --workspace --all-targets
+        run: cargo clippy --all-targets --profile ci --locked --workspace

.github/workflows/set-vars.sh

@@ -0,0 +1,23 @@
+#!/bin/sh
+
+msrv=$(
+    awk '/^rust-version = "[[:digit:]]+\.[[:digit:]]+\.[[:digit:]]+"$/ {
+      print substr($NF, 2, length($NF) - 2)
+    }' Cargo.toml
+)
+if [ -z $msrv ]; then
+    printf "Could not determine Rust toolchain version\n"
+    exit 1
+fi
+
+git fetch --depth=1 origin +refs/tags/*:refs/tags/*
+if ! git diff HEAD~1 --quiet -- "$UBUNTU_DOCKERFILE" ||
+    git describe --candidates=0; then
+    should_build=true
+else
+    should_build=false
+fi
+
+echo "msrv=$msrv" >> "$GITHUB_OUTPUT"
+echo "should_build=$should_build" >> "$GITHUB_OUTPUT"
+echo "container_path=$REGISTRY/$1" >> "$GITHUB_OUTPUT"

.github/workflows/ubuntu.dockerfile

@@ -0,0 +1,9 @@
+FROM ubuntu:latest
+
+ARG DEBIAN_FRONTEND=noninteractive
+ENV TZ=Etc/UTC
+RUN apt-get update \
+	&& apt-get install -y xwayland libxcb1 clang libxcb-cursor0 libxcb-cursor-dev curl pkg-config libegl1 \
+	&& rm -r /var/lib/apt/lists/*
+RUN mkdir /run/xwls-test
+ENV XDG_RUNTIME_DIR="/run/xwls-test"