DCD-224: Refactor downloads to be more explicit about the version cache file.

roles/product_download/tasks/main.yml

@@ -1,25 +1,52 @@
 ---
 
+- name: Check for existing version cache file
+  stat:
+    path: "{{ atl_product_version_cache }}"
+  register: cached
+
+# Case: File exists, always use its value
+- name: Use version for product version
+  block:
+
+    - name: Read cached version from file
+      command: "cat {{ atl_product_version_cache }}"
+      register: atl_product_version_file
+      changed_when: false
+
+    - name: Set the local var to cached version
+      set_fact:
+        atl_product_version: "{{ atl_product_version_file.stdout }}"
+
+  when: cached.stat.exists
+
+
+# Case: File doesn't exist and no version has been set; find latest.
 - name: Fetch and cache latest version when no override
   block:
+
     - name: Fetch the latest version from URL
       set_fact:
         atl_product_version_json: "{{ lookup('url', '{{ atl_product_latest_version_url }}') }}"
-    - name: Set the local var to fetched version
+
+    - name: Set the local var to retrieved version
       set_fact:
         atl_product_version: "{{ atl_product_version_json.version }}"
-  when: atl_product_version is undefined or atl_product_version == "latest"
 
+  when:
+    not cached.stat.exists and
+    (atl_product_version is undefined or
+     not atl_product_version or
+     atl_product_version == "latest")
+
+
+# At this point atl_product_version should be set, cache if necessary.
 - name: Write override cached version when specified
   template:
     src: version.j2
     dest: "{{ atl_product_version_cache }}"
     force: false
 
-- name: Use version for product version
-  command: "cat {{ atl_product_version_cache }}"
-  register: atl_product_version_file
-  changed_when: false
 
 # Note: We don't cache this in the shared drive to the complexity
 # around download race-conditions if multiple nodes are starting at
@@ -34,7 +61,7 @@
 
 - name: Create target version directory
   file:
-    path: "{{ atl_product_installation_base }}/{{ atl_product_version_file.stdout }}"
+    path: "{{ atl_product_installation_base }}/{{ atl_product_version }}"
     state: directory
     owner: "{{ atl_product_user }}"
 
@@ -42,8 +69,8 @@
   unarchive:
     remote_src: true
     src: "{{ atl_product_download }}"
-    dest: "{{ atl_product_installation_base }}/{{ atl_product_version_file.stdout }}"
-    creates: "{{ atl_product_installation_base }}/{{ atl_product_version_file.stdout }}/bin/catalina.sh"
+    dest: "{{ atl_product_installation_base }}/{{ atl_product_version }}"
+    creates: "{{ atl_product_installation_base }}/{{ atl_product_version }}/bin/catalina.sh"
     owner: "{{ atl_product_user }}"
     group: "{{ atl_product_user }}"
     mode: 0755
@@ -53,7 +80,7 @@
 
 - name: Symlink the installed version to current
   file:
-    src: "{{ atl_product_installation_base }}/{{ atl_product_version_file.stdout }}"
+    src: "{{ atl_product_installation_base }}/{{ atl_product_version }}"
     dest: "{{ atl_product_installation_target }}"
     state: link
     force: true