Build role: support using sources from directory

Support copying sources from ready directories in addition
to cloning from repository. It's good both for CI -
when using cloned by ZUUL repos and for local development.
Remove built data from previous runs from DLRN folder.

Change-Id: I99ec5dfcc2ca05d133a125e6d53383ff86c65e1c

roles/build-test-packages/README.md

@@ -28,6 +28,8 @@ Role Variables
   This is useful if the project is directly checked out by the gate job as this
   retains "Depends-On" functionality for the rest of the projects. Also useful
   to skip projects that DLRN cannot build.
+* `artg_repos_dir` -- Root directory which contains project directories with
+   sources for build.
 
 ```yaml
 artg_change_list:

roles/build-test-packages/tasks/dlrn-build.yml

@@ -32,12 +32,22 @@
   args:
       chdir: '{{ ansible_user_dir }}/DLRN'
 
+- name: Create data directory if doesn't exist yet
+  file: path="{{ ansible_user_dir }}/DLRN/data/" state=directory
+
 - name: Clone the gated change
   git:
     repo: 'https://{{ artg_change.host }}/{{ artg_change.project }}'
     dest: '{{ ansible_user_dir }}/DLRN/data/{{ project_name_mapped.stdout }}'
     refspec: '{{ artg_change.refspec }}'
     version: 'FETCH_HEAD'
+  when: artg_repos_dir is not defined
+
+- name: Copy from ready directories if configured
+  command: >
+    cp -raf {{ artg_repos_dir }}/{{ artg_change.project|regex_replace('openstack[^/]*/', '') }}
+    {{ ansible_user_dir }}/DLRN/data/{{ project_name_mapped.stdout }}
+  when: artg_repos_dir is defined
 
 - name: Run DLRN
   shell: >

roles/build-test-packages/tasks/main.yml

@@ -33,6 +33,12 @@
   stat: path='{{ ansible_user_dir }}/DLRN'
   register: dlrn_cloned
 
+- name: Remove data files from previous runs
+  file:
+    path: '{{ ansible_user_dir }}/DLRN/data'
+    state: absent
+  when: dlrn_cloned.stat.exists
+
 - name: Clone DLRN
   git:
     repo: '{{ artg_dlrn_repo_url }}'