bash script to create a relative virtualenv that can be packaged in an rpm

create-relative-virtualenv

#!/usr/bin/env bash

me=$(basename $0)
set -e # exit on error

function print_help {
echo
echo $me - create a virtualenv with relative paths in a certain buildroot and fix the relative path to make it work after install
echo
echo OPTIONS
echo "	-h / --help"
echo "		show this help summary"
echo "	-p / --path"
echo "		the path where the virtualenv should be installed"
echo "	-r / --requirements"
echo "		requirements.txt or Pipfile (Pipfile.lock will be used)"
echo "		DEFAULT=requirements.txt"
echo "	-v / --version"
echo "		pip version number to use (2 by default)"
echo
echo "EXAMPLE"
echo
echo "$me -p \$RPM_BUILD_ROOT/usr/lib/application"
echo "$me -p \$RPM_BUILD_ROOT/usr/lib/application -r requirements.txt"
exit
}

TEMP=$(getopt -o hp:r:v: --long help,path:,requirements:,version: -- "$@")
eval set -- "$TEMP"

VENVPATH=
REQUIREMENTS=requirements.txt
VERSION=2
while true
do
	case "$1" in
		-h | --help ) print_help ; exit 0 ;;
		-p | --path ) VENVPATH="$2"; shift 2;;
		-r | --requirements ) REQUIREMENTS="$2"; shift 2;;
		-v | --version ) VERSION="$2"; shift 2;;
		-- ) if [ -n "$2" ]
			then
				shift
				echo "Unexpected options: \"$@\" . exiting."
				exit 1;
			fi
			shift; break;;
		* ) break ;;
	esac
done

# check if we have the correct variables set
[ -z "$VENVPATH" ] && echo "ERROR: you need to specify the virtualenv path" && exit 1
[ -z "$REQUIREMENTS" ] && echo "ERROR: you need to specify the requirements file" && exit 1

if [ -e $VENVPATH/virtualenv ]
then
	echo "removing pre-existing $VENVPATH/virtualenv"
	rm -rf $VENVPATH/virtualenv
fi

# Note: Pipenv expects a path to a given Pipfile, thus it is impossible for him to
# read a Pipfile.lock, either it will fail because it is expecting a .toml formatted file.
if [ "$REQUIREMENTS" == "Pipfile" ]
then
	# Installing pipenv and upgrading setuptools on user level
	ABSPATH_PIPFILE=$(realpath $REQUIREMENTS)
	PIPFILE_LOCK="${ABSPATH_PIPFILE}.lock"
	if [ ! -f $PIPFILE_LOCK ]
	then
		echo "ERROR: The given Pipfile has no locked dependencies (Pipfile.lock not found)"
		exit 1
	else
		python$VERSION -m pip install --user --upgrade setuptools pipenv
		# Give the path to the pipfile, avoid locale related errors and (most important one)
		# tell pipenv to create the virtualenvironment inside the project directory, under .venv dir.
		LANG=en_US.UTF-8 LC_ALL=en_US.UTF-8 PIPENV_PIPFILE=$ABSPATH_PIPFILE PIPENV_VENV_IN_PROJECT=1 python$VERSION -m pipenv --python $VERSION sync
		# rename to virtualenv for backwards compatibility
		mkdir -p $VENVPATH
		mv .venv $VENVPATH/virtualenv
	fi
else
	# Installing virtualenv and upgrading setuptools on user level
	python$VERSION -m pip install --user --upgrade setuptools virtualenv
	# Create virtualenv
	python$VERSION -m virtualenv --python=python$VERSION $VENVPATH/virtualenv
	# this is to have a distribute virtualenv
	python$VERSION -m virtualenv --python=python$VERSION --relocatable --distribute $VENVPATH/virtualenv

	# activate virtualenv to install requirements
	source $VENVPATH/virtualenv/bin/activate
	# a first pass to upgrade the setuptools since this caused trouble for some dependencies.
	# We suppose that upgraded setuptools won't cause any trouble for other packages.
	$VENVPATH/virtualenv/bin/pip install "setuptools>=24.3"
	# install the requirements
	$VENVPATH/virtualenv/bin/pip install -r $REQUIREMENTS
fi

# for some reason there is a 'local' directory on ubuntu with symbolic links.
# this creates problems: upon installation these still point to the temporary build directories
# the postinstall scripts where we change file permissions then change file permissions in the temporary build directories which cannot be removed
# for the moment let's just remove this local directory. It is not created on other environments anyways
rm -rf $VENVPATH/virtualenv/local

# remove all pycaches
find $VENVPATH/virtualenv/ -name __pycache__ -type d -prune -exec rm -rf {} +

# make sure this is a full path to avoid problems when replacing this in virtualenv/bin
VENVPATH=$(realpath $VENVPATH)

# replace paths in RPM_BUILD_ROOT with the relative paths
find $VENVPATH/virtualenv/lib/python$VERSION*/site-packages/ -type f -exec sed -i "s|$VENVPATH/virtualenv/|/../|g" {} \;

# seek pyo file and pyc file to delete it
find $VENVPATH/virtualenv -name '*.py[co]' -delete

# remove pip from the virtualenv
for file in pip activate easy_install python-config
do
	rm -f $VENVPATH/virtualenv/bin/$file*
done
for package in pip easy_install
do
	rm -rf $VENVPATH/virtualenv/lib*/python*/site-packages/$package*
done

# prepare a script that will be called to run any generated binary with the local python
# we do that because we can't just modify the shebang and replace it with relative path
# as shebang can't execute relative path
# scripts have extension 'script.pyw' because the generated python inside strips this extension (why ?)
# and this is nicer when the python script print its own name (for example for help)
cat <<END >$VENVPATH/virtualenv/bin/run-with-local-python
#!/usr/bin/env bash
FILE=\$0-script.pyw
BIN=\$(dirname \$0)/python
exec \$BIN \$FILE "\$@"
END
chmod 0755 $VENVPATH/virtualenv/bin/run-with-local-python

# replace binaries that have the virtualenv python in their shebang to a symlink to run-with-local-python
for binary in $(find $VENVPATH/virtualenv/bin/ -maxdepth 1 -type f -executable ! -name "python*")
do
	if head -n 1 $binary | grep -q -e '^#!.*python*'
	then
		tail -n +2 $binary > $binary-script.pyw
	elif head -n 1 $binary | grep -q -e '^#!/bin/sh$'
	then
		# when  the filepath is too long, python-virtualenv creates a multiline shebang in this form:
		# #!/bin/sh
		# '''exec' /home/chris/rpmbuild/BUILDROOT/application-1.2.3-0/usr/lib/application/virtualenv/bin/python3.6 "$0" "$@"
		# ' '''
		if [ -z "$(head -n 3 $binary | grep -ve '^#!/bin/sh' | grep -ve "^'''" | grep -ve "'''$")" ]
		then
			# we made the matching pattern very strict; so normally we shouldn't have any wrong matches... now just remove the top three lines
			tail -n +4 $binary > $binary-script.pyw
		fi
	fi
	if [ -e $binary-script.pyw ]
	then
		chmod 0755 $binary-script.pyw
		rm $binary
		ln -s run-with-local-python $binary
	fi
done