Merge lp:~laney/ubuntu-cdimage/stop-sync-mirrors into lp:ubuntu-cdimage

[Iain Lane]

mirror: Add a flag file etc/STOP_SYNC_MIRRORS to stop syncing

Our current method of `chmod -x bin/sync-mirrors` doesn't work. In particular, the mirrors are triggered whenever any daily build is completed. This means that in progress releases are highly vulnerable to leaking early. In the past we have asked Canonical IS to stop rsync to prevent this from happening. But we can take care of it on our side by avoiding ever asking the frontends to pull from us.

A better API where we can ask frontends to only sync *certain* images - thedaily which just finished - would be preferable.

[Steve Langasek (vorlon)]

review: Approve

=== modified file 'lib/cdimage/mirror.py'
--- lib/cdimage/mirror.py	2015-10-26 11:06:11 +0000
+++ lib/cdimage/mirror.py	2021-02-16 10:35:39 +0000
@@ -117,6 +117,14 @@
 
 
 def trigger_mirrors(config):
+    paths = [
+        os.path.join(config.root, "production", "STOP_SYNC_MIRRORS"),
+        os.path.join(config.root, "etc", "STOP_SYNC_MIRRORS"),
+    ]
+    for path in paths:
+        if os.path.exists(path):
+            return
+
     check_manifest(config)
 
     key = _get_mirror_key(config)

=== modified file 'lib/cdimage/tests/test_mirror.py'
--- lib/cdimage/tests/test_mirror.py	2019-02-27 22:57:25 +0000
+++ lib/cdimage/tests/test_mirror.py	2021-02-16 10:35:39 +0000
@@ -17,7 +17,7 @@
 
 """Unit tests for cdimage.mirror."""
 
-from __future__ import print_function
+from __future__ import print_function, with_statement
 
 import os
 
@@ -224,3 +224,11 @@
             mock.call(
                 self.config, key, "archvsync", "bar-async", background=True),
         ])
+
+    @mock.patch("cdimage.mirror._trigger_mirror")
+    def test_no_trigger_mirrors_when_stopped(self, mock_trigger_mirror):
+        self.configure_triggers()
+        os.mkdir(os.path.join(self.config.root, "etc"))
+        with open(os.path.join(self.config.root, "etc", "STOP_SYNC_MIRRORS"), "w"):
+            trigger_mirrors(self.config)
+            mock_trigger_mirror.assert_not_called()