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.

Depends-On: https://review.openstack.org/598957
Change-Id: Ia84e9f0a7b7627182e4b10aa3fc4f0d708edfee8
Implements: blueprint python-build-install-simplification
Signed-off-by: Jesse Pretorius <jesse.pretorius@rackspace.co.uk>

defaults/main.yml

@@ -28,7 +28,18 @@ blazar_developer_mode: false
 blazar_requirements_git_repo: https://git.openstack.org/openstack/requirements
 blazar_requirements_git_install_branch: master
 
-blazar_venv_tag: untagged
+# 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.
+blazar_pip_install_args: >-
+  {{ blazar_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('') }}
+
+blazar_venv_tag: "{{ venv_tag | default('untagged') }}"
 blazar_bin: "/openstack/venvs/blazar-{{ blazar_venv_tag }}/bin"
 
 blazar_venv_download_url: http://127.0.0.1/venvs/untagged/ubuntu/blazar.tgz

handlers/main.yml

@@ -19,4 +19,7 @@
     name: "{{ item.service_name }}"
     state: restarted
   with_items: "{{ filtered_blazar_services }}"
-  failed_when: false
+  retries: 5
+  delay: 2
+  listen:
+    - "venv changed"

tasks/blazar_install.yml

@@ -14,29 +14,12 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-- name: Install distro packages
-  package:
-    name: "{{ blazar_distro_packages }}"
-    state: "{{ blazar_package_state }}"
-    update_cache: "{{ (ansible_pkg_mgr in ['apt', 'zypper']) | 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
-
-- name: Install distro packages
-  package:
-    name: "{{ almanach_developer_mode_distro_packages }}"
-    state: "{{ blazar_package_state }}"
-    update_cache: "{{ (ansible_pkg_mgr in ['apt', 'zypper']) | ternary('yes', omit) }}"
-    cache_valid_time: "{{ (ansible_pkg_mgr == 'apt') | ternary(cache_timeout, omit) }}"
-  when: blazar_developer_mode | bool
-  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"
@@ -46,79 +29,23 @@
       {% endfor %}
   when: blazar_developer_mode | bool
 
-- name: Retrieve checksum for venv download
-  uri:
-    url: "{{ blazar_venv_download_url | replace('tgz', 'checksum') }}"
-    return_content: yes
-  register: blazar_venv_checksum
-  when: blazar_venv_download | bool
-
-- name: Attempt venv download
-  get_url:
-    url: "{{ blazar_venv_download_url }}"
-    dest: "/var/cache/{{ blazar_venv_download_url | basename }}"
-    checksum: "sha1:{{ blazar_venv_checksum.content | trim }}"
-  register: blazar_get_venv
-  when: blazar_venv_download | bool
-
-- name: Remove existing venv
-  file:
-    path: "{{ blazar_bin | dirname }}"
-    state: absent
-  when: blazar_get_venv is changed
-
-- name: Create blazar venv dir
-  file:
-    path: "{{ blazar_bin | dirname }}"
-    state: directory
-  register: blazar_venv_dir
-  when: blazar_get_venv is changed
-
-- name: Unarchive pre-built venv
-  unarchive:
-    src: "/var/cache/{{ blazar_venv_download_url | basename }}"
-    dest: "{{ blazar_bin | dirname }}"
-    copy: "no"
-  when: blazar_get_venv is changed
-  notify:
-    - Restart blazar services
-
-- name: Install pip packages
-  pip:
-    name: "{{ blazar_pip_packages | join(' ') }}"
-    state: "{{ blazar_pip_package_state }}"
-    virtualenv: "{{ blazar_bin | dirname }}"
-    virtualenv_site_packages: "no"
-    extra_args: >-
-      {{ blazar_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: blazar_get_venv is failed or blazar_get_venv is skipped
-  notify:
-    - Restart blazar services
-
-- name: Remove python from path first (CentOS, openSUSE)
-  file:
-    path:  "{{ blazar_bin | dirname }}/bin/python2.7"
-    state: "absent"
+- name: Ensure remote wheel building is disabled in developer mode
+  set_fact:
+    venv_build_host: "{{ ansible_hostname }}"
   when:
-    - ansible_pkg_mgr in ['yum', 'dnf', 'zypper']
-    - blazar_get_venv is changed
+    - blazar_developer_mode | bool
 
-- name: Update virtualenv path
-  shell: |
-    find {{ blazar_bin }} -name \*.pyc -delete
-    sed -si '1s/^.*python.*$/#!{{ blazar_bin | replace ('/','\/') }}\/python/' {{ blazar_bin }}/*
-    virtualenv {{ blazar_bin | dirname }}
-  when: blazar_get_venv is changed
-
-- name: Record the venv tag deployed
-  ini_file:
-    dest: "/etc/ansible/facts.d/openstack_ansible.fact"
-    section: blazar
-    option: venv_tag
-    value: "{{ blazar_venv_tag }}"
+- name: Install the python venv
+  include_role:
+    name: "python_venv_build"
+    private: yes
+  vars:
+    venv_build_distro_package_list: "{{ blazar_devel_distro_packages }}"
+    venv_install_destination_path: "{{ blazar_bin | dirname }}"
+    venv_install_distro_package_list: "{{ blazar_distro_packages }}"
+    venv_pip_install_args: "{{ blazar_pip_install_args }}"
+    venv_pip_packages: "{{ blazar_pip_packages }}"
+    venv_facts_when_changed:
+      - section: "blazar"
+        option: "venv_tag"
+        value: "{{ blazar_venv_tag }}"

vars/ubuntu.yml

@@ -23,14 +23,13 @@ blazar_distro_packages:
   - libxslt1-dev
   - libzip-dev
   - build-essential
-  - build-essential
   - libssl-dev
   - libffi-dev
   - python-setuptools
   - python-mysqldb
   - python-systemd
 
-almanach_developer_mode_distro_packages:
+blazar_devel_distro_packages:
   - build-essential
   - libsystemd-dev
   - pkg-config