Optionally silence git in mirror-workspace-git-repos

Especially when using Github branch and push workflows repos can
easily have hundreds of branches.  The role mirror-workspace-git-repos
which pushes them onto the node prints all of them in every
build. This can get quite messy. Thus we need to optionally be able to
silence the git push operation. This is done on purpose by the --quiet
parameter instead of using no_log because this way errors are still
logged normally and normal operation produces no log output for this
task.

Change-Id: Id77cc00972df9139e4544dd79954d91f4ab6b60b

roles/mirror-workspace-git-repos/README.rst

@@ -4,3 +4,11 @@ This role uses git operations (unlike :zuul:role:`prepare-workspace`
 which uses rsync) to mirror the local prepared git repos to the remote
 nodes.  This may be useful if the remote node already has a copy of
 some or all of the git repos.
+
+**Role Variables**
+
+.. zuul:rolevar:: mirror_workspace_quiet
+   :default: false
+
+   If `true` git operations will be silenced and won't print every
+   changed reference.

roles/mirror-workspace-git-repos/defaults/main.yaml

@@ -0,0 +1 @@
+mirror_workspace_quiet: false

roles/mirror-workspace-git-repos/tasks/main.yaml

@@ -7,7 +7,7 @@
   with_dict: "{{ zuul.projects }}"
 
 - name: Synchronize src repos to workspace directory
-  command: "git push --mirror git+ssh://{{ ansible_user }}@{{ ansible_host | ipwrap }}:{{ ansible_port }}/{{ ansible_user_dir }}/{{ item.value.src_dir}}"
+  command: "git push {% if mirror_workspace_quiet %}--quiet{% endif %} --mirror git+ssh://{{ ansible_user }}@{{ ansible_host | ipwrap }}:{{ ansible_port }}/{{ ansible_user_dir }}/{{ item.value.src_dir}}"
   args:
     chdir: "{{ zuul.executor.work_root }}/{{ item.value.src_dir }}"
   with_dict: "{{ zuul.projects }}"
@@ -32,7 +32,7 @@
     # Undo the config setting we did above
     git config --local --unset receive.denyCurrentBranch
     # checkout the branch matching the branch set up by the executor
-    git checkout {{ item.value.checkout }}
+    git checkout {% if mirror_workspace_quiet %}--quiet{% endif %} {{ item.value.checkout }}
     # put out a status line with the current HEAD
     echo "{{ item.value.canonical_name }} checked out to:"
     git log --pretty=oneline  -1