Make ssh-rsync.check check VERSION_LABEL

As well as checking whether it's defined,
we make sure there isn't already a system named $VERSION_LABEL

Note, this depends on the new json-list feature of system-version-manager.

Change-Id: I0dee5253ba95a002b493f4179c2acda734afc37a

1 files changed, 18 insertions, 0 deletions

diff --git a/extensions/ssh-rsync.check b/extensions/ssh-rsync.check
index 436aaae0..fc9bf62d 100755
--- a/extensions/ssh-rsync.check
+++ b/extensions/ssh-rsync.check
@@ -17,6 +17,8 @@
 
 
 import os
+import json
+import logging
 
 import writeexts
 
@@ -40,6 +42,8 @@ class SshRsyncCheckExtension(writeexts.WriteExtension):
 
         location = args[0]
         self.check_ssh_connectivity(location)
+
+        self.check_version_label(location, os.environ['VERSION_LABEL'])
         self.check_is_baserock_system(location)
 
         # The new system that being deployed as an upgrade must contain
@@ -62,5 +66,19 @@ class SshRsyncCheckExtension(writeexts.WriteExtension):
             raise writeexts.ExtensionError(
                 "%s does not have %s" % (location, command))
 
+    def check_version_label(self, location, version_label):
+        args = ['system-version-manager', 'list', '--json']
+
+        try:
+            output = writeexts.ssh_runcmd(location, args)
+        except writeexts.ExtensionError:
+            msg = ("Couldn't get system list from system-version-manager, "
+                   "skipping version label check")
+            logging.exception(msg)
+            return
+
+        if version_label in json.loads(output):
+            raise writeexts.ExtensionError(
+                    "There is already a system called `%s'" % version_label)
 
 SshRsyncCheckExtension().run()