fetch-javascript-content-tarball: add create_tarball variable

This change enable publish job to also create the tarball before fetch.

Change-Id: If4b5a1be8d3ce61ff45b04be23cf80a802760ec8

roles/fetch-javascript-content-tarball/README.rst

@@ -9,3 +9,8 @@ such as but not limited to those produced by the webpack ArchivePlugin.
    :default: {{ zuul.project.src_dir }}
 
    Directory to work in.
+
+.. zuul:rolevar:: create_tarball_directory
+
+   Create a tarball with the contents of create_tarball_directory
+   (relative to zuul_work_dir).

roles/fetch-javascript-content-tarball/tasks/main.yaml

@@ -1,3 +1,12 @@
+- name: Create tarball
+  shell: "tar czf {{ zuul_work_dir }}/build.tgz *"
+  args:
+    chdir: "{{ zuul_work_dir }}/{{ create_tarball_directory }}"
+  when: create_tarball_directory is defined
+  tags:
+    # Ignore ANSIBLE0006: tar used in place of unarchive module
+    - skip_ansible_lint
+
 - name: Rename tarball for uploading
   shell: |
     mkdir -p dist