Pave Android NDK when building Docker image

ClientLibrary/Dockerfile

@@ -28,4 +28,16 @@ RUN curl -L https://storage.googleapis.com/golang/$GOVERSION.linux-amd64.tar.gz
    && rm /tmp/go.tar.gz \
    && echo $GOVERSION > $GOROOT/VERSION
 
+# Setup Android Environment.
+ENV ANDROID_NDK_VERSION=r17b
+ENV ANDROID_NDK_TOOLCHAIN_ROOT=/android-ndk-toolchain
+
+# Setup Android NDK
+RUN cd /tmp \
+  && curl https://dl.google.com/android/repository/android-ndk-${ANDROID_NDK_VERSION}-linux-x86_64.zip -o /tmp/android-ndk.zip \
+  && unzip /tmp/android-ndk.zip -d / \
+  && mkdir -p /android-ndk-toolchain \
+  && /android-ndk-${ANDROID_NDK_VERSION}/build/tools/make_standalone_toolchain.py --arch arm --install-dir /android-ndk-toolchain/arm \
+  && /android-ndk-${ANDROID_NDK_VERSION}/build/tools/make_standalone_toolchain.py --arch arm64 --install-dir /android-ndk-toolchain/arm64
+
 WORKDIR $GOPATH/src/github.com/Psiphon-Labs/psiphon-tunnel-core/ClientLibrary

ClientLibrary/make.bash

@@ -65,28 +65,19 @@ build_for_android () {
   fi
   prepare_build android
 
-  TARGET_NDK=android-ndk-r17b
-  curl https://dl.google.com/android/repository/${TARGET_NDK}-linux-x86_64.zip -o ~/android-ndk.zip
-  unzip ~/android-ndk.zip -d ~/
-
-  NDK_TOOLCHAIN_DIR=~/android-ndk-toolchain
-  mkdir -p ${NDK_TOOLCHAIN_DIR}
-
   TARGET_ARCH=arm
   ARMV=7
-  ~/${TARGET_NDK}/build/tools/make_standalone_toolchain.py --arch "${TARGET_ARCH}" --install-dir "${NDK_TOOLCHAIN_DIR}/${TARGET_ARCH}"
 
-  CC="${NDK_TOOLCHAIN_DIR}/${TARGET_ARCH}/bin/arm-linux-androideabi-clang" \
-  CXX="${NDK_TOOLCHAIN_DIR}/${TARGET_ARCH}/bin/arm-linux-androideabi-clang++" \
+  CC="${ANDROID_NDK_TOOLCHAIN_ROOT}/${TARGET_ARCH}/bin/arm-linux-androideabi-clang" \
+  CXX="${ANDROID_NDK_TOOLCHAIN_ROOT}/${TARGET_ARCH}/bin/arm-linux-androideabi-clang++" \
   GOARM=${ARMV} \
   GOOS=${TARGET_OS} GOARCH=${TARGET_ARCH} go build -buildmode=c-shared -ldflags "$LDFLAGS" -tags "${BUILD_TAGS}" -o "${OUTPUT_DIR}/${TARGET_ARCH}${ARMV}/libpsiphontunnel.so" PsiphonTunnel.go
 
 
   TARGET_ARCH=arm64
-  ~/${TARGET_NDK}/build/tools/make_standalone_toolchain.py --arch "${TARGET_ARCH}" --install-dir "${NDK_TOOLCHAIN_DIR}/${TARGET_ARCH}"
 
-  CC="${NDK_TOOLCHAIN_DIR}/${TARGET_ARCH}/bin/aarch64-linux-android-clang" \
-  CXX="${NDK_TOOLCHAIN_DIR}/${TARGET_ARCH}/bin/aarch64-linux-android-clang++" \
+  CC="${ANDROID_NDK_TOOLCHAIN_ROOT}/${TARGET_ARCH}/bin/aarch64-linux-android-clang" \
+  CXX="${ANDROID_NDK_TOOLCHAIN_ROOT}/${TARGET_ARCH}/bin/aarch64-linux-android-clang++" \
   GOOS=${TARGET_OS} GOARCH=${TARGET_ARCH} go build -buildmode=c-shared -ldflags "$LDFLAGS" -tags "${BUILD_TAGS}" -o "${OUTPUT_DIR}/${TARGET_ARCH}/libpsiphontunnel.so" PsiphonTunnel.go
 
 }