Add Constraints support

Adding constraints support to libraries is slightly more complex than
services as the libraries themselves are listed in upper-constraints.txt
which leads to errors that you can't install a specific version and a
constrained version.

This change adds constraints support by also adding a helper script to
edit the constraints to remove stevedore.

Change-Id: I7a1285a2c3882b02987bfa95950689f5282aa407

tools/tox_install.sh

@@ -0,0 +1,30 @@
+#!/usr/bin/env bash
+
+# Client constraint file contains this client version pin that is in conflict
+# with installing the client from source. We should remove the version pin in
+# the constraints file before applying it for from-source installation.
+
+CONSTRAINTS_FILE="$1"
+shift 1
+
+set -e
+
+# NOTE(tonyb): Place this in the tox enviroment's log dir so it will get
+# published to logs.openstack.org for easy debugging.
+localfile="$VIRTUAL_ENV/log/upper-constraints.txt"
+
+if [[ "$CONSTRAINTS_FILE" != http* ]]; then
+    CONSTRAINTS_FILE="file://$CONSTRAINTS_FILE"
+fi
+# NOTE(tonyb): need to add curl to bindep.txt if the project supports bindep
+curl "$CONSTRAINTS_FILE" --insecure --progress-bar --output "$localfile"
+
+pip install -c"$localfile" openstack-requirements
+
+# This is the main purpose of the script: Allow local installation of
+# the current repo. It is listed in constraints file and thus any
+# install will be constrained and we need to unconstrain it.
+edit-constraints "$localfile" -- "$CLIENT_NAME"
+
+pip install -c"$localfile" -U "$@"
+exit $?

tox.ini

@@ -1,7 +1,13 @@
 [tox]
+minversion = 2.0
 envlist = py35,py34,py27,pep8,docs
 
 [testenv]
+setenv =
+    VIRTUAL_ENV={envdir}
+    BRANCH_NAME=master
+    CLIENT_NAME=stevedore
+install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 deps =
   -r{toxinidir}/test-requirements.txt
 distribute = False