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 oslo.db.

Change-Id: I31febfe00698e36f4c2e0e41c3f7bf64acf47adf

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

@@ -1,13 +1,16 @@
 [tox]
-minversion = 1.8
+minversion = 2.0
 envlist = py35,py34,py27,pep8,pip-missing-reqs
 
 [testenv]
+install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 whitelist_externals = bash
                       env
 setenv =
    VIRTUAL_ENV={envdir}
    BASECOMMAND=bash tools/pretty_tox.sh
+   BRANCH_NAME=master
+   CLIENT_NAME=oslo.db
 
    {postgresql,all}: PIFPAF_POSTGRESQL=pifpaf -g OS_TEST_DBAPI_ADMIN_CONNECTION run postgresql --
    {mysql,all}: PIFPAF_MYSQL=pifpaf -g OS_TEST_DBAPI_ADMIN_CONNECTION run mysql --