[PATCH v2 3/4] Machine: compare LNST versions of Controller and Slaves

[Jiri Prochazka]

This patch implements version check between Controller and Slaves. Check
is done after hello messages are exchanged. Controller extracts Slave
version slave_desc dict and compares with its own version.

These situations might happen:
1) Versions match - everything continues as normally
2) Versions mismatch:
  a) Both Ctl and Slave are run from git repo - warning message is shown,
   but execution continues
  b) Ctl/Slave is run from git repo but the second one is run from RPM
   installation - exception is raised and execution is stopped

changes in v2:
* logging warning message is now multiline - decorated with '='
* replaced method compare_versions with is_git_version

Signed-off-by: Jiri Prochazka <jprochaz(a)redhat.com&gt;
---
 lnst/Controller/Machine.py | 23 +++++++++++++++++++++++
 1 file changed, 23 insertions(+)

diff --git a/lnst/Controller/Machine.py b/lnst/Controller/Machine.py
index c5d9191..3e730bd 100644
--- a/lnst/Controller/Machine.py
+++ b/lnst/Controller/Machine.py
@@ -247,6 +247,22 @@ class Machine(object):
                   "to machine %s, handshake failed!" % hostname
             raise MachineError(msg)
 
+        slave_version = slave_desc["lnst_version"]
+        slave_is_git = self.is_git_version(slave_version)
+        ctl_version = lnst_config.version
+        ctl_is_git = self.is_git_version(ctl_version)
+        if slave_version != ctl_version:
+            if ctl_is_git and slave_is_git:
+                msg = "Controller and Slave '%s' git versions are
different"\
+                                                                    % hostname
+                logging.warning(len(msg)*"=")
+                logging.warning(msg)
+                logging.warning(len(msg)*"=")
+            else:
+                msg = "Controller and Slave '%s' versions are not
compatible!"\
+                                                                    % hostname
+                raise MachineError(msg)
+
         self._slave_desc = slave_desc
 
         devices = self._rpc_call("get_devices")
@@ -258,6 +274,13 @@ class Machine(object):
 
         self._configured = True
 
+    def is_git_version(self, version):
+        try:
+            int(version)
+            return False
+        except ValueError:
+            return True
+
     def is_configured(self):
         """ Test if the machine was configured """
 
-- 
2.4.11