environment setup for ROS 2 development

.envrc

#!/usr/bin/env bash
# This file is meant to be run by direnv. Direnv will execute your script with bash, even if you're using another shell.

printf '─%.0s' $(seq $(tput cols))

################## CMake Generator (Cmake 3.15+)

# If available, use Ninja buildsystem generator, which is faster
# but Colcon may not show compiler output on a failed build
# if [ -x "$(command -v ninja)" ]; then
# 	export CMAKE_GENERATOR="Ninja"
# fi

################## Python

export PATH="/usr/local/opt/python/libexec/bin:$PATH"

################## CHOOSE A COMPILER

# Clang tends to give better error messages but has stricter warnings
# export CC=gcc CXX=g++
if [ -x "$(command -v clang)" ]; then
	export CC=clang CXX=clang++
fi

# Use CCache to cache compiler output
if [ -x "$(command -v ccache)" ]; then
	export CC="ccache $CC" CXX="ccache $CXX"
fi

# If available, use lld linker, which is faster. Install with: sudo apt install lld
if [ -x "$(command -v lld)" ]; then
	LDFLAGS+=" -fuse-ld=lld"
fi

# Use LLVM Project's C++ implementation. Install with: sudo apt install libc++-dev libc++abi-dev
ldconfig -p -N | grep -q libc++
if [ $? -eq 0 ]; then
	export CXXFLAGS+=" -stdlib=libc++"
fi

# enable low-performance-impact sanitizers to tell us if we break something
# export SAN_FLAGS=-fsanitize-trap=undefined
# export CFLAGS="$SAN_FLAGS"
# export CXXFLAGS="$SAN_FLAGS"
# export UBSAN_OPTIONS=print_stacktrace=1

################# CHOOSE A ROS BASE DISTRIBUTION

# UNDERLAY=/opt/ros/dashing
# UNDERLAY=/opt/ros/eloquent
UNDERLAY=/opt/ros/foxy
# UNDERLAY=/opt/ros/rolling
# UNDERLAY= # no underlay

################# CHOOSE A MIDDLEWARE

# export RMW_IMPLEMENTATION=rmw_connext_cpp
export RMW_IMPLEMENTATION=rmw_cyclonedds_cpp
# export RMW_IMPLEMENTATION=rmw_fastrtps_cpp
# export RMW_IMPLEMENTATION=rmw_fastrtps_dynamic_cpp
# export RMW_IMPLEMENTATION=rmw_gurumdds_cpp

################# ROS Underlay

if [ -z "$UNDERLAY" ]; then
	echo "No underlay path specified. Not using an underlay."
else
	DID_UNDERLAY_SETUP=0
	for UNDERLAY_SETUP in "$UNDERLAY/install/setup.bash" "$UNDERLAY/setup.bash"
	do
		# if setup files change (on build), rerun this script.
		watch_file $UNDERLAY_SETUP
		test -f "$UNDERLAY_SETUP" && echo "running underlay script $UNDERLAY_SETUP..." && source "$UNDERLAY_SETUP" && DID_UNDERLAY_SETUP=1
	done
	if [ $DID_UNDERLAY_SETUP = 0 ]; then
		echo "Failed to run underlay script"
	fi
fi

################# ROS Workspace

OVERLAY_SETUP=./install/local_setup.bash

# if setup files change (on build), rerun this script.
watch_file $OVERLAY_SETUP

if [ -f "$OVERLAY_SETUP" ]; then
	source $OVERLAY_SETUP
else
	echo "Did not find overlay setup. Has this workspace been built yet?"
fi

################# CONFIGURE MIDDLEWARE

### Configure Fast RTPS
# export FASTRTPS_DEFAULT_PROFILES_FILE=$PWD/fastrtps_profiles.xml

### Configure Connext
## Select Connext root installation home
# export NDDSHOME=/opt/rti.com/rti_connext_dds-5.3.1
# export NDDSHOME=/opt/rti.com/rti_connext_dds-6.0.1 
# generates the below variables, so no need to actually call this:
## source $NDDSHOME/resource/scripts/rtisetenv_x64Linux3gcc5.4.0.bash
# export RTI_LICENSE_FILE=$NDDSHOME/rti_license.dat
# export LD_LIBRARY_PATH=$NDDSHOME/lib/:$LD_LIBRARY_PATH
# export PATH=$NDDSHOME/bin:$PATH

################# Runtime preferences

export ROS_DOMAIN_ID=42 # make this number different than your coworkers' to isolate your ROS from theirs
# export COLCON_HOME=/opt/ros/_common/colcon
# export COLCON_DEFAULTS_FILE=$PWD/colcon.yaml

python3 -c "
import platform, os
print()
print('System:', platform.system(), platform.release())
print('Python:', platform.python_implementation(), platform.python_version())
print('   RMW:', os.environ.get('RMW_IMPLEMENTATION','?'))
print('   ROS:', os.environ.get('ROS_DISTRO','distro?'))
print('🤖 Welcome to ROS on', platform.node())
print()
"