Add Docker build for Linux

Adds support for building Linux binaries inside a docker container in
order to target an older version of GLIBC.

Updates GitHub Actions workflow to use it.

As a result the minimum version of GLIBC that Linux users need to have
installed on their system is 2.17 which was released in 2012.

.github/workflows/main.yml

@@ -17,18 +17,59 @@ env:
   GODOT_CACHE_VERSION: 1
 
 jobs:
-  build:
-    name: 'Build'
+  build_docker:
+    name: 'Build Docker (linux, ${{ matrix.target }}, ${{ matrix.bits }})'
+    runs-on: ubuntu-latest
+    strategy:
+      fail-fast: false
+      matrix:
+        target: [ release, debug ]
+        bits: [ 64, 32 ]
+    steps:
+      - uses: actions/checkout@v2
+        with:
+          submodules: recursive
+      - name: Cache submodules
+        uses: ./.github/actions/cache-submodules
+        id: cache-submodules
+        with:
+          platform: linux
+          target: ${{ matrix.target }}
+          bits: ${{ matrix.bits }}
+      - name: Pull docker images
+        run: docker-compose pull
+        working-directory: addons/godot_xterm/native
+      - name: Cache docker image layers
+        uses: satackey/action-docker-layer-caching@v0.0.11
+        continue-on-error: true
+      - name: Build godot-cpp bindings
+        if: steps.cache-submodules.outputs.cache-hit != 'true'
+        working-directory: addons/godot_xterm/native
+        run: UID_GID="$(id -u):$(id -g)" docker-compose run -e TARGET=${{ matrix.target }} -e BITS=${{ matrix.bits }} godot-cpp-linux
+      - name: Build libuv
+        if: steps.cache-submodules.outputs.cache-hit != 'true'
+        working-directory: addons/godot_xterm/native
+        run: UID_GID="$(id -u):$(id -g)" docker-compose run -e TARGET=${{ matrix.target }} -e BITS=${{ matrix.bits }} libuv-linux
+      - name: Build libgodot-xterm
+        working-directory: addons/godot_xterm/native
+        run: UID_GID="$(id -u):$(id -g)" docker-compose run -e TARGET=${{ matrix.target }} -e BITS=${{ matrix.bits }} libgodot-xterm-linux
+      - name: Upload binaries
+        uses: actions/upload-artifact@v2
+        with:
+          name: libgodot-xterm-${{ matrix.target }}
+          path: |
+            addons/godot_xterm/native/bin/*.so
+
+  build_native:
+    name: 'Build Native'
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false
       matrix:
-        platform: [ linux, javascript, osx, windows ]
+        platform: [ javascript, osx, windows ]
         target: [ release, debug ]
         bits: [ 64, 32 ]
         include:
-          - platform: linux
-            os: ubuntu-latest
           - platform: javascript
             os: ubuntu-latest
           - platform: osx
@@ -59,40 +100,31 @@ jobs:
         with:
           path: addons/godot_xterm/native/.emcache
           key: emsdk-cache-${{ matrix.target }}-v${{ env.EMSCRIPTEN_CACHE_VERSION }}
-
-      # Ubuntu-specific steps.
-      - name: Install ubuntu build dependencies
-        if: ${{ matrix.os == 'ubuntu-latest' }}
-        run: sudo apt-get update && sudo apt-get install -y scons gcc-multilib g++-multilib
-
-      # JavaScript-specific steps.
       - name: Install javascript build dependencies
         if: ${{ matrix.platform == 'javascript' }}
         uses: mymindstorm/setup-emsdk@v11
         with:
           version: 3.1.5
           actions-cache-folder: emsdk-cache-${{ matrix.target }}
-
-      # MacOS-specific steps.
+      - name: Install additional javascript build dependencies
+        if: ${{ matrix.platform == 'javascript' }}
+        run: sudo apt-get update && sudo apt-get install -y scons gcc-multilib g++-multilib
       - name: Install additional macos build dependencies
         if: ${{ matrix.os == 'macos-latest' }}
         run: brew install scons
-
-      # Windows-specific steps.
       - name: Install additional windows build dependencies
         if: ${{ matrix.os == 'windows-latest' }}
         run: python -m pip install scons
-      - uses: ilammy/msvc-dev-cmd@v1.9.0
+      - name: Setup MSVC command prompt
+        uses: ilammy/msvc-dev-cmd@v1.9.0
         if: ${{ matrix.os == 'windows-latest' }}
         with:
           arch: win${{ matrix.bits }}
-
       - name: Build godot-cpp bindings
         if: steps.cache-submodules.outputs.cache-hit != 'true'
         run: |
           cd addons/godot_xterm/native/thirdparty/godot-cpp
           scons platform=${{ matrix.platform }} target=${{ matrix.target }} bits=${{ matrix.bits }} generate_bindings=yes -j2
-
       - name: Setup cmake
         if: steps.cache-submodules.outputs.cache-hit != 'true'
         uses: jwlawson/actions-setup-cmake@v1.9
@@ -125,23 +157,19 @@ jobs:
             cd ..
           fi
           cmake --build build --config $TARGET
-
       - name: Build libgodot-xterm
         run: |
           cd addons/godot_xterm/native
           scons platform=${{ matrix.platform }} target=${{ matrix.target }} bits=${{ matrix.bits }} -j2
-
-      - name: Upload build artifacts
+      - name: Upload binaries
         uses: actions/upload-artifact@v2
         with:
           name: libgodot-xterm-${{ matrix.target }}
           path: |
-            addons/godot_xterm/native/bin/*.so
             addons/godot_xterm/native/bin/*.wasm
             addons/godot_xterm/native/bin/*.dylib
             addons/godot_xterm/native/bin/*.dll
 
-
   # GDNative HTML5 export templates aren't provided so we must build them
   export_template:
     name: 'Export Template'
@@ -198,7 +226,7 @@ jobs:
 
   html5_export:
     name: 'HTML5 Export'
-    needs: [ build, export_template ]
+    needs: [ build_docker, build_native, export_template ]
     runs-on: ubuntu-latest
     steps:
     - uses: actions/checkout@v2
@@ -233,7 +261,7 @@ jobs:
 
   test:
     name: 'Test'
-    needs: [ install_plugins, build ]
+    needs: [ install_plugins, build_docker, build_native ]
     runs-on: ${{ matrix.os }}
     strategy:
       fail-fast: false

CHANGELOG.md

@@ -11,6 +11,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   `libgodot-xterm.osx.64.dylib` is now a universal binary that runs natively
   on both x86_64 and arm64.
 
+### Changed
+- Linux binaries now support systems with older GLIBC versions. By building the
+  binaries inside a docker container with an older GLIBC version, the minimum
+  required GLIBC version is now 2.17 which was released in 2012.
+
 ### Fixed
 - The `kill()` method of unix PTY node can now be called without error as the underlying
   `pipe.close()` method of the gdnative library is now registered.

addons/godot_xterm/native/.dockerignore

@@ -0,0 +1 @@
+*

addons/godot_xterm/native/SConstruct

@@ -282,7 +282,7 @@ else:
     else:
         #sources.append('src/node_pty/win/conpty.cc')
         env.Append(LIBS=[
-            env.File(f'thirdparty/libuv/build/{env["target"].capitalize()}/uv_a.lib'),
+            env.File('thirdparty/libuv/build/{}/uv_a.lib'.format(env["target"].capitalize())),
             'Advapi32.lib',
             'Iphlpapi.lib',
             'user32.lib',

addons/godot_xterm/native/docker-compose.yaml

@@ -12,3 +12,46 @@ services:
         scons platform=javascript target=$${TARGET:-debug} -j$$(nproc)
         cd /src
         scons platform=javascript target=$${TARGET:-debug} -j$$(nproc)
+  godot-cpp-linux:
+    user: ${UID_GID}
+    build:
+      context: .
+      dockerfile: linux.Dockerfile
+    volumes:
+      - ./thirdparty/godot-cpp:/godot-cpp
+    working_dir: /godot-cpp
+  libuv-linux:
+    user: ${UID_GID}
+    build:
+      context: .
+      dockerfile: linux.Dockerfile
+    volumes:
+      - ./thirdparty/libuv:/libuv
+    working_dir: /libuv
+    command:
+      - /bin/bash
+      - -c
+      - |
+        target=$${TARGET:-release}
+        bits=$${BITS:-'64'}
+        mkdir build 2>/dev/null ;
+        args="-DCMAKE_BUILD_TYPE=$$target \
+          -DBUILD_SHARED_LIBS=OFF \
+          -DCMAKE_POSITION_INDEPENDENT_CODE=TRUE"
+        if [[ $$bits -eq 32 ]]; then
+          args="$$args -DCMAKE_SYSTEM_PROCESSOR=i686 -DCMAKE_C_FLAGS=-m32";
+        else
+          args="$$args -DCMAKE_SYSTEM_PROCESSOR=x86_64 -DCMAKE_C_FLAGS=";
+        fi
+        pushd build
+        cmake .. $$args
+        popd
+        cmake --build build
+  libgodot-xterm-linux:
+    user: ${UID_GID}
+    build:
+      context: .
+      dockerfile: linux.Dockerfile
+    volumes:
+      - .:/godot-xterm
+    working_dir: /godot-xterm

addons/godot_xterm/native/linux.Dockerfile

@@ -0,0 +1,7 @@
+# Uses an old version of Ubuntu in order to target an old version of GLIBC so users
+# with older versions of GLIBC installed on their systems can use the library.
+FROM kroggen/ubuntu-16.04-gcc
+RUN apt-get update -y
+RUN apt-get install -y python3 python3-pip gcc-multilib g++-multilib
+RUN pip3 install scons
+CMD scons platform=linux generate_bindings=yes target=${TARGET:-release} bits=${BITS:-64} -j$(nproc)