ERSAP C++ Binding

An Environment for Realtime Streaming Acquisition and Processing, designed to process unbounded streams of continuous data at scale over distributed heterogeneous resources.

Build Status Javadoc

Documentation

In progress…

Build notes

ERSAP requires a C++17 compiler and CMake 3.5+

Ubuntu 18.04 and 20.04

Install GCC and CMake from the repositories:

$ sudo apt install build-essential cmake

macOS

Install Xcode command line tools:

$ xcode-select --install

Install CMake using Homebrew:

$ brew install cmake

Dependencies

ERSAP is built on top of the xMsg pub-sub messaging system, which requires Protocol Buffers and ZeroMQ.

xMsg is bundled with ERSAP, and it will be built automatically.

Ubuntu 18.04 and 20.04

Install from the repositories:

$ sudo apt install libzmq5-dev libprotobuf-dev protobuf-compiler

macOS

Use Homebrew:

$ brew install zeromq protobuf

Installation

To build with CMake a configure wrapper script is provided:

$ ./configure --prefix="$ERSAP_HOME"
$ make
$ make install

This installs ERSAP C++ into the location of your ERSAP distribution.

Install layout

ERSAP honours CMake’s GNUInstallDirs, so the native binaries follow the host’s convention:

Host CMAKE_INSTALL_LIBDIR Where native binaries land
Debian / Ubuntu, macOS lib $ERSAP_HOME/lib/{libersap.so, libxmsg.so, ersap/c_dpe, pkgconfig/, cmake/}
RHEL / EL / Fedora (64-bit) lib64 $ERSAP_HOME/lib64/{libersap.so, libxmsg.so, ersap/c_dpe, pkgconfig/, cmake/}

Either way, the installed $ERSAP_HOME/bin/c_dpe wrapper is templated at build time to point at the right libdir, so there’s nothing to configure on the user side. Pass -DCMAKE_INSTALL_LIBDIR=lib by hand only if you need to override the default (for example when packing a Docker image where you want jars and natives in a single lib/):

$ cmake -S . -B build -DCMAKE_INSTALL_PREFIX="$ERSAP_HOME" -DCMAKE_INSTALL_LIBDIR=lib
$ cmake --build build -j && cmake --install build

Runtime library resolution

On Linux the installed libersap.so / libxmsg.so carry a RUNPATH that includes $ORIGIN plus every directory CMake saw at link time (protobuf, abseil, Boost, ZeroMQ, …). As long as those libraries were present at build time, the installed objects resolve under ldd without any LD_LIBRARY_PATH or /etc/ld.so.conf.d/* edits. On macOS the equivalent is handled by @loader_path.

Interoperation with ERSAP Java

The main ERSAP Java implementation should also be installed in $ERSAP_HOME to run C++ services with the standard orchestrator and the ERSAP shell. Its jars and run-java wrapper always live in $ERSAP_HOME/lib/ (arch-neutral content), so Java and native sides coexist cleanly on both lib-style and lib64-style hosts.

Authors

For assistance send email to ersap@jlab.org.