Fix failing gate jobs by fixing constraints support

Recently we added python-masakariclient to global-requirements [1]
as a requirement library for masakari-monitors. python-masakariclient
itself is a library and adding upper 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 python-masakariclient.

This patch is a copy of commit: 78f113780510b741bc974c69eb9b0718cd657c1d

For failing jobs please refer: https://review.openstack.org/#/c/492989/

[1] 1cd2c8da1a6534c23959cd0a4035e7f530471386

Change-Id: I9376ee14ebfb9186c1480276b47939c3ffc30108

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

@@ -5,11 +5,11 @@ skipsdist = True
 
 [testenv]
 usedevelop = True
-install_command = pip install -c{env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
+install_command = {toxinidir}/tools/tox_install.sh {env:UPPER_CONSTRAINTS_FILE:https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt} {opts} {packages}
 setenv = VIRTUAL_ENV={envdir}
-         OS_TEST_PATH=./masakariclient/tests/unit
-         LANGUAGE=en_US
-         LC_ALL=en_US.utf-8
+         BRANCH_NAME=master
+         CLIENT_NAME=python-masakariclient
+
 deps = -r{toxinidir}/test-requirements.txt
 whitelist_externals = bash
                       find