Simplify pip options/constraints mechanism

The current constraints generation for the
installation involves multiple tasks and multiple
variables.

Using multiple tasks extends the installation time
unnecessarily and the additional variables are
unnecessary.

This patch aims to simplify the mechanism and
hopes to speed it up a little.

Change-Id: I9bdbe46c56893c3eeb0312065dfddcf32127c97f

defaults/main.yml

@@ -21,8 +21,6 @@ sahara_pip_package_state: "latest"
 
 sahara_git_repo: https://git.openstack.org/openstack/sahara
 sahara_git_install_branch: master
-sahara_requirements_git_repo: https://git.openstack.org/openstack/requirements
-sahara_requirements_git_install_branch: master
 sahara_developer_mode: false
 sahara_developer_constraints:
   - "git+{{ sahara_git_repo }}@{{ sahara_git_install_branch }}#egg=sahara"

releasenotes/notes/remove-requirements-git-59f58bcf4e54a569.yaml

@@ -0,0 +1,7 @@
+---
+upgrade:
+  - The variables ``sahara_requirements_git_repo`` and
+    ``sahara_requirements_git_install_branch`` have been
+    removed in favour of using the URL/path to the
+    upper-constraints file using the
+    variable ``pip_install_upper_constraints`` instead.

tasks/sahara_install.yml

@@ -25,33 +25,13 @@
   when:
     - sahara_developer_mode | bool
 
-- name: Clone requirements git repository
-  git:
-    repo: "{{ sahara_requirements_git_repo }}"
-    dest: "/opt/requirements"
-    clone: yes
-    update: yes
-    version: "{{ sahara_requirements_git_install_branch }}"
-  when:
-    - sahara_developer_mode | bool
-
-- name: Add constraints to pip_install_options fact for developer mode
-  set_fact:
-    pip_install_options_fact: "{{ pip_install_options|default('') }} --constraint /opt/developer-pip-constraints.txt --constraint /opt/requirements/upper-constraints.txt"
-  when:
-    - sahara_developer_mode | bool
-
-- name: Set pip_install_options_fact when not in developer mode
-  set_fact:
-    pip_install_options_fact: "{{ pip_install_options|default('') }}"
-  when:
-    - not sahara_developer_mode | bool
-
 - name: Install required pip packages
   pip:
     name: "{{ sahara_required_pip_packages | join(' ') }}"
     state: present
-    extra_args: "{{ pip_install_options_fact }}"
+    extra_args: >-
+      {{ (pip_install_upper_constraints is defined) | ternary('--constraint ' + pip_install_upper_constraints | default(''),'') }}
+      {{ pip_install_options | default('') }}
   register: install_packages
   until: install_packages|success
   retries: 5
@@ -109,7 +89,10 @@
     state: "{{ sahara_pip_package_state }}"
     virtualenv: "{{ sahara_bin | dirname }}"
     virtualenv_site_packages: "no"
-    extra_args: "{{ pip_install_options_fact }}"
+    extra_args: >-
+      {{ sahara_developer_mode | ternary('--constraint /opt/developer-pip-constraints.txt', '') }}
+      {{ (pip_install_upper_constraints is defined) | ternary('--constraint ' + pip_install_upper_constraints | default(''),'') }}
+      {{ pip_install_options | default('') }}
   register: install_packages
   until: install_packages|success
   retries: 5