Use Docker images to build Linux versions to provide compatibility for older glibc versions

.github/workflows/build.yml

@@ -4,39 +4,97 @@ on:
     branches: [ master ]
 jobs:
   build:
-    runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
-        os: [windows-latest, macos-15, ubuntu-24.04, ubuntu-24.04-arm]
+        config:
+        - {
+            name: "Windows Latest",
+            os: windows-latest
+          }
+        - {
+            name: "macOS 15",
+            os: macos-15
+          }
+        - {
+            name: "Ubuntu 22.04",
+            os: ubuntu-latest,
+            container_image: "ubuntu:22.04"
+          }
+        - {
+            name: "Ubuntu 22.04 ARM64",
+            os: ubuntu-24.04-arm,
+            container_image: "ubuntu:22.04"
+          }
+
+    runs-on: ${{ matrix.config.os }}
+    container:
+      image: ${{ matrix.config.container_image }}
+
     steps:
       - name: Setup Windows
-        if: matrix.os == 'windows-latest'
+        if: matrix.config.os == 'windows-latest'
         uses: ilammy/msvc-dev-cmd@v1
       - name: Setup NASM for Windows
-        if: matrix.os == 'windows-latest'
+        if: matrix.config.os == 'windows-latest'
         uses: ilammy/setup-nasm@v1.2.1
+      - name: Setup build tools for containers
+        if: matrix.config.container_image != null
+        env:
+          # Prevent tzdata (pulled in by cmake/build-essential) from launching an
+          # interactive timezone prompt that hangs the build with no TTY attached.
+          DEBIAN_FRONTEND: noninteractive
+          TZ: Etc/UTC
+        run: |
+          apt-get update
+          apt-get install -y build-essential git libssl-dev zlib1g-dev file zip curl jq cmake
+          # clang-16 is not in Ubuntu 22.04 (jammy), whose newest is clang-15.
+          # Add the official LLVM apt repo to install it.
+          . /etc/os-release
+          apt-get install -y wget gnupg
+          wget -qO- https://apt.llvm.org/llvm-snapshot.gpg.key | gpg --dearmor -o /usr/share/keyrings/llvm.gpg
+          echo "deb [signed-by=/usr/share/keyrings/llvm.gpg] http://apt.llvm.org/$VERSION_CODENAME/ llvm-toolchain-$VERSION_CODENAME-16 main" > /etc/apt/sources.list.d/llvm.list
+          apt-get update
+          apt-get install -y clang-16
+          # Ubuntu 22.04's bare "clang" is clang-14, which lacks __builtin_source_location
+          # and cannot compile Node 26's V8 headers (std::source_location). Force clang-16.
+          update-alternatives --install /usr/bin/clang clang /usr/bin/clang-16 100
+          update-alternatives --install /usr/bin/clang++ clang++ /usr/bin/clang++-16 100
+          echo "::group::Environment info"
+          echo "--- distro ---"
+          cat /etc/os-release
+          echo "--- architecture ---"
+          uname -a
+          dpkg --print-architecture
+          echo "--- glibc ---"
+          # ldd --version prints the glibc version on the first line; getconf gives it raw.
+          ldd --version | head -n 1
+          getconf GNU_LIBC_VERSION
+          echo "--- compiler ---"
+          clang --version
+          clang++ --version
+          echo "::endgroup::"
       - name: Setup Node.js
         uses: actions/setup-node@v4
         with:
           node-version: 26
       - name: Update binaries
         run: |
-          git clone --recursive https://github.com/uNetworking/uWebSockets.js.git
+          git clone --recursive https://github.com/uNetworking/uWebSockets.js.git -b master
           cd uWebSockets.js
-          ${{ matrix.os == 'windows-latest' && 'nmake' || 'make' }}
+          ${{ matrix.config.os == 'windows-latest' && 'nmake' || 'make' }}
           ls dist
           cd tests && npm install ws && node smoke.js && cd ..
           ls dist
           git fetch origin binaries:binaries
           git checkout binaries
           cp dist/*.node .
           cp dist/*.js .
-          git rev-parse master > source_commit
+          git rev-parse origin/master > source_commit
           ls
-          ${{ matrix.os != 'windows-latest' && 'git checkout master docs/index.d.ts && mv docs/index.d.ts .' || '' }}
+          ${{ matrix.config.os != 'windows-latest' && 'git checkout master docs/index.d.ts && mv docs/index.d.ts .' || '' }}
           git status
           git config --global user.email "alexhultman@gmail.com"
           git config --global user.name "Alex Hultman"
-          git commit -a -m "[GitHub Actions] Updated ${{ matrix.os }} binaries" || true
+          git commit -a -m "[GitHub Actions] Updated ${{ matrix.config.os }} binaries" || true
           git push "https://unetworkingab:${{ secrets.SECRET }}@github.com/uNetworking/uWebSockets.js" binaries

build.c

@@ -213,8 +213,8 @@ int main() {
 
 #else
     /* Linux does not cross-compile but picks whatever arch the host is on (we run on both x64 and ARM64) */
-    build("clang-18",
-          "clang++-18",
+    build("clang",
+          "clang++",
           LINUX_LINK_EXTRAS,
           OS,
           arch);