Auto-compose of kubevirt_web_ui_image_name for kubevirt-apb flow (#450)

The docker image:tag can be either provided explicitely by
setting `kubevirt_web_ui_image_name` or
it can be newly determined automatically from
`registry_url`, `registry_namespace`, `docker_tag` and `version`
variables, as they are supplied by kubevirt-apb.

playbooks/kubevirt-web-ui/README.md

@@ -3,12 +3,21 @@ Used for deployment of the [Kubevirt Web UI](https://github.com/kubevirt/web-ui)
 
 The playbook is based on [opensift-ansible](https://github.com/openshift/openshift-ansible/tree/master/playbooks/openshift-console).
 
+## Kubevirt Web UI Image name and tag
+One of following must be set:
+- either `kubevirt_web_ui_image_name` variable (when set, takes precedence over automatic composition of image:tag)
+  - example: quay.io/kubevirt/kubevirt-web-ui:latest
+  - The docker image with the kubevirt-web-ui application
+- or `registry_url, registry_namespace, docker_tag, version` (as used in kubevirt-apb flow)
+  - `registry_url` example: quay.io
+  - `registry_namespace` example: kubevirt
+  - one of following:
+    - `docker_tag` example: 1.3.0-3 or 1.3 (note: there's no 'v' preffixed)
+    - `version`  example: 0.9.3
+
 ### Required Variables
 - `cluster`
   - To install Kubevirt Web UI, please set `cluster=openshift`
-- `kubevirt_web_ui_image_name`
-  - example: quay.io/kubevirt/kubevirt-web-ui:latest
-  - The docker image with the kubevirt-web-ui application
 
 ### Optional Variables:
 - `openshift_master_default_subdomain`
@@ -28,8 +37,12 @@ From the hosts, just the master node is required.
 
 Please check `playbooks/kubevirt-web-ui/inventory_example.ini` for an example.
 
-### Invocation
+### Invocation examples
 ```
-ansible-playbook -i your_inventory_file.ini playbooks/kubevirt-web-ui/config.yml -e "apb_action=provision cluster=openshift"
+ansible-playbook -i your_inventory_file.ini playbooks/kubevirt-web-ui/config.yml -e "apb_action=provision cluster=openshift registry_url=quay.io registry_namespace=kubevirt docker_tag=1.3" # to mimic kubevirt-apb flow
+ansible-playbook -i your_inventory_file.ini playbooks/kubevirt-web-ui/config.yml -e "apb_action=provision cluster=openshift registry_url=quay.io registry_namespace=kubevirt"  # for :latest image tag
+ansible-playbook -i your_inventory_file.ini playbooks/kubevirt-web-ui/config.yml -e "apb_action=provision cluster=openshift registry_url=quay.io registry_namespace=kubevirt version=0.9.3" # for automatic tag association or :latest as default
+
+ansible-playbook -i your_inventory_file.ini playbooks/kubevirt-web-ui/config.yml -e "apb_action=deprovision cluster=openshift kubevirt_web_ui_image_name=whatever"
 ```
 

roles/kubevirt_web_ui/tasks/required_params.yml

@@ -1,9 +1,18 @@
 ---
-#### Verify required variables
+#### Verify/set kubevirt-web-ui image:tag
+
+- set_fact: kubevirt_web_ui_image_tag="v1.3.0"
+  when: version is defined and "0.9." in version
+
+- set_fact: kubevirt_web_ui_image_tag="v{{ docker_tag }}"
+  when: docker_tag is defined
+
+- set_fact: kubevirt_web_ui_image_name="{{ registry_url }}/{{ registry_namespace }}/kubevirt-web-ui:{{ kubevirt_web_ui_image_tag | default("latest")}}"
+  when: kubevirt_web_ui_image_name is not defined and registry_url is defined and registry_namespace is defined
 
 - name: Verify required kubevirt_web_ui_image_name variable is set
   fail:
-    msg: kubevirt_web_ui_image_name must be set to deploy kubevirt-web-ui
+    msg: kubevirt_web_ui_image_name must be set to deploy kubevirt-web-ui. Alternatively registry_url, registry_namespace and docker_tag (or version) can be used for automated composition.
   when: kubevirt_web_ui_image_name is not defined
 
 #### Autodiscovery of missing variables