Add ability to set upper constraints file

When this role executes the installation of packages
for SNI support it should also respect upper constraints.

This patch adds the ability to set an upper constraint
file URL/path.

The tox config is also adjusted to ensure that it makes
use of upper constraints when installing requirements.

Change-Id: I2ab6f55096b560a7b443de412df168e26a3eca07

defaults/main.yml

@@ -32,6 +32,9 @@ pip_tmp_packages: /tmp/pip_install
 pip_get_pip_options: ""
 pip_source_install_options: ""
 
+# The URL/path of a constraints file to use when installing the additional pip packages.
+#pip_install_upper_constraints: "http://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt"
+
 # This list var can be used to specify specific versions of pip, setuptools,
 # wheel and any other packages which must be installed when pip installs.
 pip_packages:

tasks/install_source.yml

@@ -35,23 +35,32 @@
   retries: 3
   delay: 2
 
+- name: Set pip_install_options_fact (with upper constraints)
+  set_fact:
+    pip_install_options_fact: "--constraint {{ pip_install_upper_constraints }} {{ pip_install_options }}"
+  when: pip_install_upper_constraints is defined
+
+- name: Set pip_install_options_fact (without upper constraints)
+  set_fact:
+    pip_install_options_fact: "{{ pip_install_options }}"
+  when: pip_install_upper_constraints is not defined
+
 - name: Install pip packages
   pip:
     name: "{{ pip_required_pip_packages | map('quote') | join(' ') }}"
     state: latest
-    extra_args: "{{ pip_install_options }}"
+    extra_args: "{{ pip_install_options_fact }}"
   failed_when: false
   register: install_packages
   until: install_packages | success
   retries: 5
   delay: 2
 
-
 - name: Install pip packages (fall back mode)
   pip:
     name: "{{ pip_required_pip_packages | map('quote') | join(' ') }}"
     state: latest
-    extra_args: "--isolated {{ pip_install_options }}"
+    extra_args: "--isolated {{ pip_install_options_fact }}"
   when: install_packages | failed
   register: install_packages_fall_back
   until: install_packages_fall_back | success

tests/test.yml

@@ -19,6 +19,7 @@
   vars:
     pip_packages:
       - "pip==8.0.3"
+    pip_install_upper_constraints: "http://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt"
   roles:
     - role: "pip_install"
   post_tasks:

tox.ini

@@ -107,7 +107,7 @@ commands =
 # it doesn't work in OpenStack-CI yet. Once that's fixed, we can
 # drop the install_command.
 install_command =
-    pip install -U --force-reinstall {opts} {packages}
+    pip install -c https://git.openstack.org/cgit/openstack/requirements/plain/upper-constraints.txt {opts} {packages}
 
 
 [testenv:functional]