Add Constraints support and missing bindep.txt dependencies

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 os-brick.

Finally, it also adds libxml2 and libxslt to bindep.txt for use when
building lxml that is now required by oslo.vmware.

Change-Id: I3fbe4acbdf0281c91801ff7d09de6e9043915939

bindep.txt

@@ -5,3 +5,7 @@
 multipath-utils [platform:dpkg rpm]
 sg3-utils [platform:dpkg]
 sg3_utils [platform:rpm]
+libxml2-devel [platform:rpm]
+libxml2-dev [platform:dpkg]
+libxslt-devel [platform:rpm]
+libxslt1-dev [platform:dpkg]

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

@@ -5,10 +5,12 @@ skipsdist = True
 
 [testenv]
 usedevelop = True
-install_command = pip install -U {opts} {packages}
-setenv = VIRTUAL_ENV={envdir}
+setenv =
+    VIRTUAL_ENV={envdir}
+    BRANCH_NAME=master
+    CLIENT_NAME=os-brick
     PYTHONHASHSEED=0
-
+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}/requirements.txt
        -r{toxinidir}/test-requirements.txt