Adds USE_VENV to globally enable/disable use of virtual environments.
ADDITIONAL_VENV_PACKAGES is used to manually add packages that do not
appear in requirements.txt or test-requirements.txt to be installed
into each venv. Database Python bindings are handled this way when
a dataabse service is enabled.
Change-Id: I9cf298b936fd10c95e2ce5f51aab0d49d4b7f37f
There were a couple of places where TOP_DIR is missing when we do a
source of content in tools. Given that working directory can change
quite often during devstack, we need to always be explicit here.
Change-Id: I14b5699637d7f5db745bccf116f440cdcbaa8d91
Introduce the tooling to build virtual environments.
* tools/build_venv.sh: build a venv
* introduce lib/stack to house functionality extracted from stack.sh that
is needed in other places, such as Grenade; start with stack_install_service
to wrap the venv install mechanics
* declare PROJECT_VENV array to track where project venvs should be installed
* create a venv for each project defined in PROJECT_VENV in stack_install_service()
Change-Id: I508588c0e2541b976dd94569d44b61dd2c35c01c
Dean Troyer