libwally-core

Wally is a cross-platform, cross-language collection of useful primitives for cryptocurrency wallets.

Read the API documentation at https://wally.readthedocs.io.

Note that library interfaces may change slightly while the library design matures. Please see the CHANGES file to determine if the API has changed when upgrading.

Please report bugs and submit patches to Our github repository. If you wish to report a security issue, please read Our security reporting guidelines.

Platforms

Wally can currently be built for:

• Linux
• Android
• macOS
• iOS
• Windows

And can be used from:

• C and compatible languages which can call C interfaces
• C++ (see include/wally.hpp for C++ container support)
• Python 2.7+ or 3.x
• Java
• Javascript via node.js or Cordova

Building

$ ./tools/autogen.sh
$ ./configure <options - see below>
$ make
$ make check

Building on macOS

Using homebrew,

$ brew install gnu-sed

If you wish to enable the SWIG interface, you will need install the Java JDK 8 or newer, and install SWIG:

$ brew install swig

configure options

• --enable-debug. Enables debugging information and disables compiler optimisations (default: no).
• --enable-export-all. Export all functions from the wally shared library. Ordinarily only API functions are exported. (default: no). Enable this if you want to test the internal functions of the library or are planning to submit patches.
• --enable-swig-python. Enable the SWIG Python interface. The resulting shared library can be imported from Python using the generated interface file src/swig_python/wallycore/__init__.py. (default: no).
• --enable-swig-java. Enable the SWIG Java (JNI) interface. After building, see src/swig_java/src/com/blockstream/libwally/Wally.java for the Java interface definition (default: no).
• --enable-elements. Enables support for Elements features, including Liquid support.
• --enable-js-wrappers. Enable the Node.js and Cordova Javascript wrappers. This currently requires python to be available at build time (default: no).
• --enable-coverage. Enables code coverage (default: no) Note that you will need lcov installed to build with this option enabled and generate coverage reports.
• --disable-shared. Disables building a shared library and builds a static library instead.

Recommended development configure options

$ ./configure --enable-debug --enable-export-all --enable-swig-python --enable-swig-java --enable-coverage

Compiler options

Set CC=clang to use clang for building instead of gcc, when both are installed.

Python

For python development, you can build and install wally using:

$ pip install .

It is suggested you only install this way into a virtualenv while the library is under heavy development.

If you wish to explicitly choose the python version to use, set the PYTHON_VERSION environment variable (to e.g. 2, 2.7, 3 etc) before running pip or (when compiling manually) ./configure.

You can also install the binary wally releases using the released wheel files without having to compile the library, e.g.:

pip install wallycore-0.8.0-cp37-cp37m-linux_x86_64.whl

The script tools/build_python_wheels.sh builds the release files and can be used as an example for your own python projects.

Android

Android builds are currently supported for all Android binary targets using the Android NDK. The script tools/android_helpers.sh can be sourced from the shell or scripts to make it easier to produce builds:

$ export ANDROID_HOME=/opt/android-sdk
$ . ./tools/android_helpers.sh

$ android_get_arch_list
armeabi-v7a arm64-v8a x86 x86_64

# Prepare to build
$ ./tools/cleanup.sh
$ ./tools/autogen.sh

# See the comments in tools/android_helpers.sh for arguments
$ android_build_wally armeabi-v7a $ANDROID_NDK/toolchains/llvm/prebuilt/linux-x86_64 19 "--enable-swig-java"

The script tools/build_android_libraries.sh builds the Android release files and can be used as an example for your own Android projects.

Cleaning

$ ./tools/cleanup.sh

Submitting patches

Please use pull requests on github to submit. Before producing your patch you should format your changes using uncrustify version 0.60 or later. The script ./tools/uncrustify will reformat all C sources in the library as needed, with the currently chosen uncrustify options.

To reformat a single source file, use e.g.:

$ ./tools/uncrustify src/transaction.c

Or to reformat all source files, pass no arguments:

$ ./tools/uncrustify

You should also make sure the existing tests pass and if possible write tests covering any new functionality, following the existing style. You can run the tests via:

$ make check

Generating a coverage report

To generate an HTML coverage report, install lcov and use:

$ ./tools/cleanup.sh
$ ./tools/autogen.sh
$ ./configure --enable-debug --enable-export-all --enable-swig-python --enable-swig-java --enable-js_wrappers --enable-coverage
$ make
$ ./tools/coverage.sh clean
$ make check
$ ./tools/coverage.sh

The coverage report can then be viewed at ./src/lcov/src/index.html. Patches to increase the test coverage are welcome.

Users of libwally-core

Projects and products that are known to depend on or use libwally:

• Blockstream Green Command Line Wallet
• Blockstream Green Development Kit
• Blockstream Green Wallet for Android
• Blockstream Green Wallet for iOS
• Blockstream/liquid-melt
• Blockstream/liquid_multisig_issuance
• c-lightning
• gdk_rpc for bitcoind/liquidd
• GreenAddress Recovery Tool
• GreenAddress Wallet for Windows/Mac/Linux
• GreenAddress Web Files
• LibWally Swift
• Multy-Core

Please note that some of listed projects may be experimental or superseded.