integrate exmachina configuration management layer

- add exmachina code and test code
- modify plinth.py to listen for shared secret on stdin at start
  (if appropriate flag is set) and try to connect to exmachina daemon
- use exmachina to read and set /etc/hostname as a demo
- update plinth init.d script to start exmachina and share keys
- update docs with new deps and run instructions

1 files changed, 16 insertions, 12 deletions

diff --git a/modules/installed/system/config.py b/modules/installed/system/config.py
index c8b5190..b31dc60 100644
--- a/modules/installed/system/config.py
+++ b/modules/installed/system/config.py
@@ -41,20 +41,18 @@ def valid_hostname(name):
 
 def set_hostname(hostname):
     "Sets machine hostname to hostname"
-    cfg.log.info("Writing '%s' to /etc/hostname" % hostname)
-    unslurp("/etc/hostname", hostname+"\n")
+    cfg.log.info("Writing '%s' to /etc/hostname with exmachina" % hostname)
+
     try:
-        retcode = subprocess.call("/etc/init.d/hostname.sh start", shell=True)
-        if retcode < 0:
-            cfg.log.error("Hostname restart terminated by signal: return code is %s" % retcode)
-        else:
-            cfg.log.debug("Hostname restart returned %s" % retcode)
+        cfg.exmachina.augeas.set("/files/etc/hostname/*", hostname)
+        cfg.exmachina.augeas.save()
+        # don't persist/cache change unless it was saved successfuly
+        sys_store = filedict_con(cfg.store_file, 'sys')
+        sys_store['hostname'] = hostname
+        cfg.exmachina.initd.restart("hostname.sh") # is hostname.sh debian-only?
     except OSError, e:
         raise cherrypy.HTTPError(500, "Hostname restart failed: %s" % e)
 
-    sys_store = filedict_con(cfg.store_file, 'sys')
-    sys_store['hostname'] = hostname
-
 class general(FormPlugin, PagePlugin):
     url = ["/sys/config"]
     order = 30
@@ -72,8 +70,11 @@ class general(FormPlugin, PagePlugin):
 
     def main(self, message='', **kwargs):
         sys_store = filedict_con(cfg.store_file, 'sys')
+        hostname = cfg.exmachina.augeas.get("/files/etc/hostname/*")
+        # this layer of persisting configuration in sys_store could/should be
+        # removed -BLN
         defaults = {'time_zone': "slurp('/etc/timezone').rstrip()",
-                    'hostname': "gethostname()",
+                    'hostname': "hostname",
                     }
         for k,c in defaults.items():
             if not k in kwargs:
@@ -81,6 +82,8 @@ class general(FormPlugin, PagePlugin):
                     kwargs[k] = sys_store[k]
                 except KeyError:
                     exec("if not '%(k)s' in kwargs: sys_store['%(k)s'] = kwargs['%(k)s'] = %(c)s" % {'k':k, 'c':c})
+        # over-ride the sys_store cached value
+        kwargs['hostname'] = hostname
 
         ## Get the list of supported timezones and the index in that list of the current one
         module_file = __file__
@@ -120,7 +123,8 @@ class general(FormPlugin, PagePlugin):
                 old_val = sys_store['hostname']
                 try:
                     set_hostname(hostname)
-                except:
+                except Exception, e:
+                    cfg.log.error(e)
                     cfg.log.info("Trying to restore old hostname value.")
                     set_hostname(old_val)
                     raise