Add mixed setup for debian based OS

Since debian/ubuntu do not provide packages for tempest plugins, we are using
mixed setup. We install tempest as a distro package, while installing
tempest plugins from source, but without venv (for system python).
That guarantees that we have all required plugins and do tests.
To accomplish that variable tempest_plugin_install_source was
introduced.

Change-Id: I198190d601cf8a922c3afaa69a3c0e42ab075735

tasks/main.yml

@@ -49,6 +49,9 @@
   tags:
     - tempest-config
 
+- name: Flush handlers
+  meta: flush_handlers
+
 - import_tasks: tempest_run.yml
   when: tempest_run | bool
   tags:

tasks/tempest_install.yml

@@ -27,11 +27,11 @@
 
 
 # NOTE(noonedeadpunk):
-# Applying default filter for tempest_install_method is required despite the variable being defined
+# Applying default filter is required despite the variable being defined
 # in defaults as in case of non-integrated tests meta handlers from other roles might fail.
 - name: Install Tempest packages from PIP
   import_tasks: tempest_install_source.yml
-  when: (tempest_install_method | default('source')) == 'source'
+  when: (tempest_install_method | default('source')) == 'source' or (tempest_plugin_install_source | default(False))
 
 - name: Install stackviz on venv
   import_role:

tasks/tempest_install_source.yml

@@ -13,6 +13,9 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+# Note(noonedeadpunk) When tempest_plugin_install_source is true, we do not
+# want pip packages to be installed inside venv, since tempest itself is
+# installed via system packages so that plugins will be visable for tempest.
 - name: Install the python venv
   import_role:
     name: "python_venv_build"
@@ -25,6 +28,7 @@
       - section: "tempest"
         option: "venv_tag"
         value: "{{ tempest_venv_tag }}"
+  when: not tempest_plugin_install_source
 
 - name: Get tempest plugins from git
   git:
@@ -43,8 +47,8 @@
   pip:
     name: "/opt/{{ item.name|replace('-', '_') }}_{{ item.branch|replace('/', '_') }}"
     state: "{{ tempest_pip_package_state }}"
-    virtualenv: "{{ tempest_venv_bin | dirname }}"
-    virtualenv_site_packages: "no"
+    virtualenv: "{{ tempest_plugin_install_source | ternary(omit, tempest_venv_bin | dirname) }}"
+    virtualenv_site_packages: "{{ tempest_plugin_install_source | ternary(omit, 'no') }}"
     extra_args: >-
       {{ tempest_pip_install_args }}
       --isolated
@@ -59,8 +63,8 @@
   pip:
     name: "{{ item.package }}"
     state: "{{ tempest_pip_package_state }}"
-    virtualenv: "{{ tempest_venv_bin | dirname }}"
-    virtualenv_site_packages: "no"
+    virtualenv: "{{ tempest_mixed_setup | ternary(omit, tempest_venv_bin | dirname) }}"
+    virtualenv_site_packages: "{{ tempest_mixed_setup | ternary(omit, 'no') }}"
     extra_args: >-
       {{ tempest_pip_install_args }}
       --isolated

vars/main.yml

@@ -151,3 +151,11 @@ _tempest_plugins:
       repo: https://opendev.org/openstack/zaqar-tempest-plugin
       branch: master
       install: "{{ tempest_service_available_zaqar | bool }}"
+
+# Note(noonedeadpunk):
+# Ubuntu does not publish tempest plugin packages. They do
+# all their testing using the source-based installation of
+# tempest.
+# For mixed setup we are using source install tasks, except
+# that we're deploying pip packages without venv.
+tempest_plugin_install_source: "{{ ((tempest_install_method == 'distro') and (ansible_os_family | lower == 'debian')) | bool }}"