Add Linux support to CI workflow with minimal changes

- Added matrix strategy to build on both macOS and Linux
- Updated Swift setup to install Swift 6.0.3 on Linux
- Modified build.sh to detect OS and copy appropriate library (.dylib/.so)
- Updated api.py for cross-platform library loading
- Commit logic handles both .dylib and .so files appropriately

Simple approach: extends existing working CI instead of complex new workflow.

Author: miriamkw

.github/workflows/ci.yml

@@ -16,7 +16,10 @@ on:
 # Define the jobs to run in the workflow
 jobs:
   build-and-test:
-    runs-on: macos-latest  # Use macOS for Swift and iOS-specific dependencies
+    strategy:
+      matrix:
+        os: [macos-latest, ubuntu-latest]
+    runs-on: ${{ matrix.os }}
 
     steps:
       - name: Checkout code
@@ -29,8 +32,18 @@ jobs:
 
       - name: Set up Swift
         run: |
-          sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
-          sudo xcodebuild -runFirstLaunch
+          if [[ "${{ matrix.os }}" == "macos-latest" ]]; then
+            sudo xcode-select --switch /Applications/Xcode.app/Contents/Developer
+            sudo xcodebuild -runFirstLaunch
+          else
+            # Install Swift for Linux
+            wget https://download.swift.org/swift-6.0.3-release/ubuntu2404/swift-6.0.3-RELEASE/swift-6.0.3-RELEASE-ubuntu24.04.tar.gz
+            tar xzf swift-6.0.3-RELEASE-ubuntu24.04.tar.gz
+            sudo mv swift-6.0.3-RELEASE-ubuntu24.04 /usr/local/swift
+            echo "/usr/local/swift/usr/bin" >> $GITHUB_PATH
+            sudo apt update
+            sudo apt install -y build-essential libc6-dev
+          fi
 
       - name: Install dependencies
         run: |
@@ -64,9 +77,14 @@ jobs:
           git fetch origin
           git checkout -B $TARGET_BRANCH origin/$TARGET_BRANCH
           
-          # Add and commit the .dylib file
-          git add ./loop_to_python_api/libLoopAlgorithmToPython.dylib
-          git commit -m "Add generated libLoopAlgorithmToPython.dylib" || echo "No changes to commit"
+          # Add and commit the library file
+          if [[ "${{ matrix.os }}" == "macos-latest" ]]; then
+            git add ./loop_to_python_api/libLoopAlgorithmToPython.dylib
+            git commit -m "Add generated libLoopAlgorithmToPython.dylib" || echo "No changes to commit"
+          else
+            git add ./loop_to_python_api/libLoopAlgorithmToPython.so
+            git commit -m "Add generated libLoopAlgorithmToPython.so" || echo "No changes to commit"
+          fi
           
           # Push to the target branch
           git push origin $TARGET_BRANCH

build.sh

@@ -6,9 +6,22 @@ echo "Building dynamic c library from Swift code..."
 swift package clean
 swift build --configuration release
 
-# Copy the library
-if cp .build/release/libLoopAlgorithmToPython.dylib ./loop_to_python_api/; then
-    echo "Library successfully copied to the loop_to_python_api folder!"
+# Detect the operating system and copy the appropriate library
+if [[ "$OSTYPE" == "darwin"* ]]; then
+    # macOS
+    if cp .build/release/libLoopAlgorithmToPython.dylib ./loop_to_python_api/; then
+        echo "Library successfully copied to the loop_to_python_api folder!"
+    else
+        echo "Failed to copy the .dylib library to the loop_to_python_api folder."
+    fi
+elif [[ "$OSTYPE" == "linux-gnu"* ]]; then
+    # Linux
+    if cp .build/release/libLoopAlgorithmToPython.so ./loop_to_python_api/; then
+        echo "Library successfully copied to the loop_to_python_api folder!"
+    else
+        echo "Failed to copy the .so library to the loop_to_python_api folder."
+    fi
 else
-    echo "Failed to copy the library to the loop_to_python_api folder."
+    echo "Unsupported operating system: $OSTYPE"
+    exit 1
 fi

loop_to_python_api/api.py

@@ -13,7 +13,16 @@
 # swift_lib = ctypes.CDLL('python_api/libLoopAlgorithmToPython.dylib')
 
 current_dir = os.path.dirname(os.path.abspath(__file__))
-lib_path = os.path.join(current_dir, 'libLoopAlgorithmToPython.dylib')
+
+# Cross-platform library loading
+if os.name == 'posix':
+    if os.uname().sysname == 'Darwin':  # macOS
+        lib_path = os.path.join(current_dir, 'libLoopAlgorithmToPython.dylib')
+    else:  # Linux
+        lib_path = os.path.join(current_dir, 'libLoopAlgorithmToPython.so')
+else:
+    raise OSError("Unsupported operating system")
+
 swift_lib = ctypes.CDLL(lib_path)