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Building Glean from Source

Introduction​

Glean is written mainly in Haskell, and makes heavy use of Thrift for data communication and serialization, so these are the main dependencies that are needed for building Glean.

You will need​

  • Linux. The build is only tested on Linux so far; we hope to add support for other OSs in the future. We build on x86_64 and arm64v8.

  • GHC. To see which versions Glean is tested with, check the current ci.yml script. We recommend installing GHC using ghcup.

  • Cabal/cabal-install version 3.6 or later (older versions won't work). As for GHC, install these using ghcup.

Additional per-distribution setup follows.

Ubuntu​

Our CI runs on Ubuntu, so this is the most well-tested platform. If you encounter problems, the source of truth for what works is the github CI workflow. In there you can also find the version of Ubuntu we test on; older versions may or may not work, in particular using a different version of librocksdb-dev is likely to run into problems.

Install these prerequisite packages:

sudo apt-get install \
    g++ \
    cmake \
    make \
    ninja-build \
    bison \
    flex \
    git \
    curl \
    rsync \
    m4 \
    pkg-config \
    binutils-dev \
    libboost-all-dev \
    libdouble-conversion-dev \
    libdwarf-dev \
    libevent-dev \
    libfast-float-dev \
    libfftw3-dev \
    libfmt-dev \
    libgflags-dev \
    libgmock-dev \
    libgoogle-glog-dev \
    libgtest-dev \
    libiberty-dev \
    libjemalloc-dev \
    liblz4-dev \
    liblzma-dev \
    libpcre3-dev \
    librocksdb-dev \
    libsnappy-dev \
    libsodium-dev \
    libssl-dev \
    libtinfo-dev \
    libunwind-dev \
    libxxhash-dev \
    libzstd-dev \
    zlib1g-dev

Additionally if you want to build the C++ indexer:

apt install clang-15 libclang-15-dev libclang-cpp15-dev libre2-dev

Debian​

The package dependencies for Debian current are the same as above for Ubuntu.

Fedora​

Install prerequisite packages:

sudo dnf install \
    g++ \
    make \
    cmake \
    curl git \
    rsync m4 \
    ninja-build \
    binutils \
    bison flex \
    libzstd-devel \
    boost-devel \
    libevent-devel \
    double-conversion-devel \
    glog-devel \
    gflags-devel \
    zlib-devel \
    openssl-devel \
    libunwind-devel \
    libsodium-devel \
    pcre-devel \
    fftw-devel \
    xxhash-devel \
    snappy-devel \
    lz4-devel \
    gtest-devel \
    fmt-devel \
    xxhash \
    clang \
    llvm12-devel \
    libfast-float-dev

Build using Cabal​

Glean can be built and installed entirely using cabal, with:

cabal install glean

This will install the following executables in ~/.cabal/bin:

The schema source files will be installed somewhere under ~/.cabal/store (Glean knows where to find them).

Installing with cabal install is sufficient if you want to:

  • Just try it out
  • Index some source code in a supported language
  • Run queries against a DB, perhaps produced by someone else
  • Run a server (including Glass)
  • Build something that depends on Glean

If you want to make changes to the schema or work on Glean itself then you will likely need to build from source: continue to the next section.

Building from the repository​

Clone the repository:

git clone https://github.com/facebookincubator/Glean.git
cd Glean

Build hsthrift and dependencies​

Glean depends on hsthrift, folly, rocksdb and some other core libraries. We need to set paths to these that the Glean build can find the thrift compiler and associated libraries:

export LD_LIBRARY_PATH=$HOME/.hsthrift/lib:$HOME/.hsthrift/lib64:$LD_LIBRARY_PATH
export PKG_CONFIG_PATH=$HOME/.hsthrift/lib/pkgconfig:$HOME/.hsthrift/lib64/pkgconfig
export PATH=$PATH:$HOME/.hsthrift/bin

On Fedora/CentOS and possibly other non-Debian systems, you also need to set:

export LIBRARY_PATH=$HOME/.hsthrift/lib:$HOME/.hsthrift/lib64:$LIBRARY_PATH

These will build with either gcc or clang as the base C and C++ compilers. Clang is the best supported C++ compiler for this project.

Now we will clone hsthrift and build and install its dependencies:

./install_deps.sh

Build Glean​

Now you can build all the Glean parts:

cabal update
make

If everything worked, the tests should pass:

make test

At this point you can cabal install to install the executables into ~/.cabal/bin.

Tips for faster builds​

If you have 4 or more cores and at least 16G of ram, you can significantly speed up the build times by passing some flags to the build stages. On an 6 core machine with 16G of ram you might use, to save 50% or more of the build time.

./install_deps.sh --threads 6
make EXTRA_GHC_OPTS='-j4 +RTS -A128m -n2m -RTS'

Using clang++-12 and clang-12 as the C and C++ compilers can shave another 25% off the build time.