Green C/C++ SDK

GDK is a cross-platform, cross-language library for Blockstream Green wallets.

Read the API documentation at https://gdk.readthedocs.io/en/latest/

building from source

installing required software

Android ndk

If you want to target Android you will need to download the NDK and set the ANDROID_NDK env variable to the directory you uncompress it to, for example export ANDROID_NDK=$HOME/Downloads/ndk or you can add it to your bash profile ~/.bash_profile

rust

1. Install rustup: curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

2. Install default rust toolchain: rustup install 1.68.0

3. Install additional rust targets for cross-building: rustup target add aarch64-linux-android armv7-linux-androideabi i686-linux-android x86_64-linux-android x86_64-pc-windows-gnu aarch64-apple-ios x86_64-apple-ios

platform-specific dependencies

For Debian Bullseye:

sudo ./tools/bullseye_deps.sh

For Mac OSX:

Install Xcode and brew if not installed, then

brew update && brew install cmake automake autoconf libtool gnu-sed python3 pkg-config swig (optional) gnu-getopt gnu-tar
xcode-select --install

You may also need to change your PATH environment variable to add $HOME/Library/Python/3.X/bin

cmake build:

building dependencies

Using the tool in tools you can build in one go all the required dependencies for gdk

$ ./tools/builddeps.sh <options> --prefix <absolute-destination-path>

<options> are:

• --clang , --gcc , --ndk <arch> , -mingw-w64 , --iphone , iphonesimulator : (cross-)build with different compilers, on different platforms. Android build supports following <arch>s
  • armeabi-v7a
  • arm64-v8a
  • x86
  • x86_64
• --buildtype debug: in case gdk must be built in debug mode
• --parallel <jobs>: set the number of parallel process that the build-system can spawn, default to CPU count. for example:

$ ./tools/builddeps.sh --clang --prefix $HOME/prebuilt/clang

downloads, builds and installs all dependencies using clang compiler under $HOME/prebuild/clang folder

building gdk

A script located in tools is enough to cover most common build use cases

$ tools/build.sh <options>

<options> are:

• --clang , --gcc , --ndk <arch> , -mingw-w64 , --iphone , iphonesimulator : (cross-)build with different compilers, on different platforms
• --enable-tests: builds test that can be easily launched using ctest (if your cmake is <= 3.20 you need to cd into the build directory, otherwise just use --test-dir)
• --python-version <version>: builds python-wheels. <version> can be something as simple as 3, you let cmake pick the 3.X version present in your system for you. Or it can be venv to indicate cmake that you are using a virtual environment and cmake should pick whatever python interpreter you set up in it.
• --parallel <jobs>: set the number of parallel process that the build-system can spawn, default to CPU count.
• --external-deps-dir <path> the folder specificied under --prefix option when running tools/buildddeps.sh
• --install <path>: have the script invoke cmake --install and install all* artifacts produced into <path> for example

tools/build.sh --clang --external-deps-dir $HOME/prefix/clang

Build output is placed in build-<target>, e.g. build-clang, build-gcc sub-directories.

* Cmake introduces the concept of COMPONENTs .GDK install is now split into two components: gdk-runtime includes only the dynamic library (with symbol files) and the python-wheel (if built and available); gdk-dev includes static library libgreenaddress-full.a, header files and all the header files for languages bindings like java and swift. CI as well as tools/build.sh --install <path> will always install everything.

To clean:

tools/clean.sh

Docker based deps & build (apple platforms excluded)

This doesn't require any of the previous steps but requires docker installed; it will build the project

docker build -t greenaddress_sdk -f ./tools/Dockerfile .
docker run -v $PWD:/root/gdk -it greenaddress_sdk

This will open a bash shell into the container, where you can then launch builds for any platform. The docker container provided by GreenAddress comes with dependencies already built under the /prebuid folder

root@bab682a071e6:~/gdk# ./tools/build.sh --gcc --external-deps-dir /prebuid/gcc
root@bab682a071e6:~/gdk# ./tools/build.sh --clang --external-deps-dir /prebuid/clang

Debug builds

By default the build type is release. A debug build can specified as

tools/build.sh --buildtype=debug --clang

or

tools/build.sh --buildtype=debugoptimized --clang

for a debug optimized build.

Java and Python wrappers

Java and Python wrappers are available if SWIG is installed.

If JAVA_HOME is set while the library is built, a Java wrapper is built exposing the API.

Similarly, if --python-version is passed to tools/build.sh a Python wrapper is built, for example:

./tools/build.sh --install $PWD --gcc --python-version 3.9

Swift wrapper

A swift wrapper is available at GreenAddress.swift.