A Fast, Reliable, Distributed Build System.

Falcon is a build system with a focus on speed and scalability.

This project is in its early stages. We are currently mainly focused on building a proof-of-concept rather than a robust cross-platform build system.

The configuration file - the "makefile" - is designed to be human-readable but not convenient to write by hand. There are no variables, the file only contains the dependency graph of the project, with a list of rules that take several inputs to build several outputs. We consider that it is not Falcon's job to provide a powerful way to define the dependency graph. We expect this file to be generated by other tools such as CMake.

Falcon is a daemon that uses watchman to be notified of changes that occur on the files that belong to the project. The configuration file is only loaded once on startup and each time it changes. This makes incremental builds faster because at the time you trigger a build, falcon already has the graph in memory and knows what to do.

Falcon aims at being consistent and correct. For example, if you change the configuration file, Falcon should remove any stale target that no longer exists.

Falcon understands git and provides a caching mechanism so that you don't need to re-build anything when you switch to a branch you already built. Falcon ensures that the last version of your project is in cache, for every git branch.

Falcon will be Distributed. If you are working on a very large project with hundreds of thousands of files, you will be able to build changes that you pull very quickly. Falcon will be able to retrieve already built targets by querying the cache of another Falcon daemon running in a continuous build server. Why build something that someone already built for you?

Falcon uses Thrift to provide an API that will allow developers to develop applications around Falcon. Clients are able to query Falcon for the state of the project's graph, trigger builds, manage the cache, etc. Among other things, this will permit a deep integration to IDEs and editors.

Right now falcon is in a working (but experimental) state. There are still a few important missing parts:

• We plan on building a CMake generator for the graph configuration file;
• The reload of the graph configuration file is not fully working yet;
• Distributed caching is not implemented.

You need to following libraries:

• thrift-compiler, python-thrift;
• libgit2;
• libboost-program-options-dev;
• libgoogle-glog-dev;
• ijson for python (pip install ijson).

Falcon is known to compile on Ubuntu 13.10.

You will also need to build and install Watchman (https://github.com/facebook/watchman).

Falcon is known to compile on OSX 10.10.4.

you can install the needed libraries with brew.

We use CMake to build falcon.

mkdir build
cd build
cmake ..
make
sudo make install

Note: we plan on making it possible to use Falcon to build itself once we implement the CMake generator.

Falcon is made of a binary "falcond" that acts as the daemon that monitors the files of your project and builds it. We also provide a python client which you must use to trigger a build (see ./clients/python/falcon).