Use a common python build/install role

In order to radically simplify how we prepare the service
venvs, we use a common role to do the wheel builds and the
venv preparation. This makes the process far simpler to
understand, because the role does its own building and
installing. It also reduces the code maintenance burden,
because instead of duplicating the build processes in the
repo_build role and the service role - we only have it all
done in a single place.

We also change the role venv tag var to use the integrated
build's common venv tag so that we can remove the role's
venv tag in group_vars in the integrated build. This reduces
memory consumption and also reduces the duplication.

This is by no means the final stop in the simplification
process, but it is a step forward. The will be work to follow
which:

1. Replaces 'developer mode' with an equivalent mechanism
   that uses the common role and is simpler to understand.
   We will also simplify the provisioning of pip install
   arguments when doing this.
2. Simplifies the installation of optional pip packages.
   Right now it's more complicated than it needs to be due
   to us needing to keep the py_pkgs plugin working in the
   integrated build.
3. Deduplicates the distro package installs. Right now the
   role installs the distro packages twice - just before
   building the venv, and during the python_venv_build role
   execution.

Depends-On: https://review.openstack.org/598957
Change-Id: I39b071b84bd71d32940157526443c17acce56c3c
Implements: blueprint python-build-install-simplification
Signed-off-by: Jesse Pretorius <jesse.pretorius@rackspace.co.uk>

defaults/main.yml

@@ -48,8 +48,19 @@ octavia_developer_mode: false
 octavia_developer_constraints:
   - "git+{{ octavia_git_repo }}@{{ octavia_git_install_branch }}#egg=octavia"
 
+# TODO(odyssey4me):
+# This can be simplified once all the roles are using
+# python_venv_build. We can then switch to using a
+# set of constraints in pip.conf inside the venv,
+# perhaps prepared by giving a giving a list of
+# constraints to the role.
+octavia_pip_install_args: >-
+  {{ octavia_developer_mode | ternary(pip_install_developer_constraints | default('--constraint /opt/developer-pip-constraints.txt'), '') }}
+  {{ (pip_install_upper_constraints is defined) | ternary('--constraint ' + pip_install_upper_constraints | default(''), '') }}
+  {{ pip_install_options | default('') }}
+
 # Name of the virtual env to deploy into
-octavia_venv_tag: untagged
+octavia_venv_tag: "{{ venv_tag | default('untagged') }}"
 octavia_bin: "/openstack/venvs/octavia-{{ octavia_venv_tag }}/bin"
 
 octavia_venv_download_url: http://127.0.0.1/venvs/untagged/ubuntu/octavia.tgz

handlers/main.yml

@@ -24,6 +24,8 @@
     name: "{{ item.value.service_name }}"
     state: "restarted"
   with_dict: "{{ octavia_services }}"
+  listen:
+    - "venv changed"
 
 - name: Start octavia services
   service:

tasks/octavia_install.yml

@@ -13,17 +13,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- name: Install apt packages
-  package:
-    name: "{{ octavia_distro_packages }}"
-    state: "{{ octavia_package_state }}"
-    update_cache: "{{ (ansible_pkg_mgr == 'apt') | ternary('yes', omit) }}"
-    cache_valid_time: "{{ (ansible_pkg_mgr == 'apt') | ternary(cache_timeout, omit) }}"
-  register: install_packages
-  until: install_packages is success
-  retries: 5
-  delay: 2
-
+# TODO(odyssey4me):
+# This can be simplified once all the roles are using
+# python_venv_build. We can then switch to using a
+# set of constraints in pip.conf inside the venv,
+# perhaps prepared by giving a giving a list of
+# constraints to the role.
 - name: Create developer mode constraint file
   copy:
     dest: "/opt/developer-pip-constraints.txt"
@@ -33,107 +28,22 @@
       {% endfor %}
   when: octavia_developer_mode | bool
 
-- name: Retrieve checksum for venv download
-  uri:
-    url: "{{ octavia_venv_download_url | replace('tgz', 'checksum') }}"
-    return_content: yes
-  register: octavia_venv_checksum
-  when: not octavia_developer_mode | bool
-
-- name: Attempt venv download
-  get_url:
-    url: "{{ octavia_venv_download_url }}"
-    dest: "/var/cache/{{ octavia_venv_download_url | basename }}"
-    checksum: "sha1:{{ octavia_venv_checksum.content | trim }}"
-  register: octavia_get_venv
-  when: not octavia_developer_mode | bool
-
-- name: Remove existing venv
-  file:
-    path: "{{ octavia_bin | dirname }}"
-    state: absent
-  when: octavia_get_venv is changed
-
-- name: Create octavia venv dir
-  file:
-    path: "{{ octavia_bin | dirname }}"
-    state: directory
-    mode: "0755"
-  register: octavia_venv_dir
-
-- name: Unarchive pre-built venv
-  unarchive:
-    src: "/var/cache/{{ octavia_venv_download_url | basename }}"
-    dest: "{{ octavia_bin | dirname }}"
-    copy: "no"
+- name: Ensure remote wheel building is disabled in developer mode
+  set_fact:
+    venv_build_host: "{{ ansible_hostname }}"
   when:
-    - not octavia_developer_mode | bool
-    - octavia_get_venv is changed or octavia_venv_dir is changed
-  notify: Restart octavia services
+    - octavia_developer_mode | bool
 
-- name: Install pip packages
-  pip:
-    name: "{{ octavia_pip_packages }}"
-    state: "{{ octavia_pip_package_state }}"
-    virtualenv: "{{ octavia_bin | dirname }}"
-    virtualenv_site_packages: "no"
-    extra_args: >-
-      {{ octavia_developer_mode | ternary(pip_install_developer_constraints | default('--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 is success
-  retries: 5
-  delay: 2
-  when: octavia_developer_mode | bool
-  notify: Restart octavia services
-
-- name: CentOS remove python from path first
-  file:
-    path:  "{{ octavia_bin | dirname }}/bin/python2.7"
-    state: "absent"
-  when:
-    - ansible_pkg_mgr == 'yum'
-    - not octavia_developer_mode | bool
-    - octavia_get_venv is changed or octavia_venv_dir is changed
-
-# NOTE(odyssey4me):
-# We reinitialize the venv to ensure that the right
-# version of python is in the venv, but we do not
-# want virtualenv to also replace pip, setuptools
-# and wheel so we tell it not to.
-# We do not use --always-copy for CentOS/SuSE due
-# to https://github.com/pypa/virtualenv/issues/565
-- name: Update virtualenv path
-  shell: |
-    find {{ octavia_bin }} -name \*.pyc -delete
-    sed -si '1s/^.*python.*$/#!{{ octavia_bin | replace ('/','\/') }}\/python/' {{ octavia_bin }}/*
-    virtualenv {{ octavia_bin | dirname }} \
-        {{ (ansible_pkg_mgr == 'apt') | ternary('--always-copy', '') }} \
-        --no-pip \
-        --no-setuptools \
-        --no-wheel
-  when:
-    - not octavia_developer_mode | bool
-    - octavia_get_venv is changed or octavia_venv_dir is changed
-  tags:
-    - skip_ansible_lint
-
-- name: Install optional pip packages
-  pip:
-    name: "{{ octavia_optional_oslomsg_amqp1_pip_packages }}"
-    state: "{{ octavia_pip_package_state }}"
-    virtualenv: "{{ octavia_bin | dirname }}"
-    virtualenv_site_packages: "no"
-  when: octavia_oslomsg_amqp1_enabled
-  register: install_optional_packages
-  until: install_optional_packages is success
-  retries: 5
-  delay: 2
-
-- name: Record the venv tag deployed
-  ini_file:
-    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
-    section: octavia
-    option: venv_tag
-    value: "{{ octavia_venv_tag }}"
+- name: Install the python venv
+  include_role:
+    name: "python_venv_build"
+    private: yes
+  vars:
+    venv_install_destination_path: "{{ octavia_bin | dirname }}"
+    venv_install_distro_package_list: "{{ octavia_distro_packages }}"
+    venv_pip_install_args: "{{ octavia_pip_install_args }}"
+    venv_pip_packages: "{{ (octavia_oslomsg_amqp1_enabled | bool) | ternary(octavia_pip_packages + octavia_optional_oslomsg_amqp1_pip_packages, octavia_pip_packages) }}"
+    venv_facts_when_changed:
+      - section: "octavia"
+        option: "venv_tag"
+        value: "{{ octavia_venv_tag }}"