Android SDK Workflow (#3418)

### Motivation:

Android SDKs now exist and testing is good.

### Modifications:

Add an Android GitHub Actions workflow using the latest nightly image
and enable it in NIO targetting NIOCore (matching WASM testing).

### Result:

More reusable workflows and more test coverage for NIO

See this in action here (the CI job works but NIOCore fails to build):
https://github.com/apple/swift-nio/actions/runs/18718487605/job/53384086329?pr=3418

Author: rnro

.github/workflows/android_sdk.yml

@@ -0,0 +1,40 @@
+name: Android SDK
+
+permissions:
+  contents: read
+
+on:
+  workflow_call:
+    inputs:
+      env_vars:
+        type: string
+        description: "Environment variables for jobs as JSON (e.g., '{\"DEBUG\":\"1\",\"LOG_LEVEL\":\"info\"}')."
+        default: "{}"
+      additional_command_arguments:
+        type: string
+        description: "Additional arguments passed to swift build (the Android SDK will be specified). Defaults to empty."
+        default: ""
+
+jobs:
+  android-sdk:
+    name: Android Swift SDK
+    # Workaround https://github.com/nektos/act/issues/1875
+    uses: apple/swift-nio/.github/workflows/swift_test_matrix.yml@main
+    with:
+      name: "Android Swift SDK"
+      matrix_string: >-
+        {
+          "config":[
+            {
+              "name":"main Jammy",
+              "swift_version":"main",
+              "platform":"Linux",
+              "runner":"ubuntu-latest",
+              "image":"ubuntu:jammy",
+              "setup_command":"apt update -q && apt install -y -q curl jq tar && curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/install_swift_prerequisites.sh | bash && curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/install_swift_sdk.sh | INSTALL_SWIFT_BRANCH=main INSTALL_SWIFT_ARCH=x86_64 INSTALL_SWIFT_SDK=android-sdk bash && hash -r",
+              "command":"curl -s --retry 3 https://raw.githubusercontent.com/apple/swift-nio/main/scripts/swift-build-with-android-sdk.sh | bash -s --",
+              "command_arguments":"${{ inputs.additional_command_arguments }}",
+              "env":'"$env_vars_json"'
+            }
+          ]
+        }

.github/workflows/main.yml

@@ -71,6 +71,13 @@ jobs:
     with:
       additional_command_arguments: "--target NIOCore"
 
+  android-sdk:
+    name: Android Swift SDK
+    # Workaround https://github.com/nektos/act/issues/1875
+    uses: apple/swift-nio/.github/workflows/android_sdk.yml@main
+    with:
+      additional_command_arguments: "--target NIOCore"
+
   macos-tests:
     name: macOS tests
     # Workaround https://github.com/nektos/act/issues/1875

.github/workflows/pull_request.yml

@@ -105,6 +105,13 @@ jobs:
     with:
       additional_command_arguments: "--target NIOCore"
 
+  android-sdk:
+    name: Android Swift SDK
+    # Workaround https://github.com/nektos/act/issues/1875
+    uses: apple/swift-nio/.github/workflows/android_sdk.yml@main
+    with:
+      additional_command_arguments: "--target NIOCore"
+
   release-builds:
     name: Release builds
     uses: apple/swift-nio/.github/workflows/release_builds.yml@main

scripts/install_swift_sdk.sh

@@ -53,6 +53,10 @@ case "$sdk" in
     sdk_dir="wasm-sdk"
     sdk_suffix="_wasm"
     ;;
+  "android-sdk")
+    sdk_dir="android-sdk"
+    sdk_suffix="_android-0.1"
+    ;;
   *)
     fatal "Unexpected Swift SDK: $sdk"
     ;;

scripts/swift-build-with-android-sdk.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+##===----------------------------------------------------------------------===##
+##
+## This source file is part of the SwiftNIO open source project
+##
+## Copyright (c) 2025 Apple Inc. and the SwiftNIO project authors
+## Licensed under Apache License v2.0
+##
+## See LICENSE.txt for license information
+## See CONTRIBUTORS.txt for the list of SwiftNIO project authors
+##
+## SPDX-License-Identifier: Apache-2.0
+##
+##===----------------------------------------------------------------------===##
+
+set -uo pipefail
+
+# Select the Swift SDK for Android
+SWIFT_SDK="$(swift sdk list | grep android | head -n1)"
+if [[ -z "$SWIFT_SDK" ]]; then
+  echo "No Android Swift SDK found. Please ensure you have the Android Swift SDK installed."
+  exit 1
+fi
+
+echo "Using Swift SDK: $SWIFT_SDK"
+swift build --swift-sdk "$SWIFT_SDK" "${@}"