Add better status messages

This patch adds better status messages by differentiating between
configuration settings received and the verification of ssh credentials.

Signed-off-by: Adam Israel <adam.israel@canonical.com>

juju-charms/layers/pingpong/reactive/pingpong.py

@@ -10,20 +10,29 @@ from charms.reactive import (
     remove_state as remove_flag,
     set_state as set_flag,
     when,
+    when_not,
 )
 import charms.sshproxy
-from subprocess import (
-    Popen,
-    CalledProcessError,
-    PIPE,
-)
+# from subprocess import (
+#     Popen,
+#     CalledProcessError,
+#     PIPE,
+# )
 
 
 cfg = config()
 
 
-@when('config.changed')
+@when('config.changed', 'sshproxy.configured')
 def config_changed():
+    """Verify the configuration.
+    Verify that the charm has been configured
+    """
+    (validated, output) = charms.sshproxy.verify_ssh_credentials()
+    if not validated:
+        status_set('blocked', 'Unable to verify SSH credentials: {}'.format(
+            output
+        ))
     if all(k in cfg for k in ['mode']):
         if cfg['mode'] in ['ping', 'pong']:
             set_flag('pingpong.configured')
@@ -32,6 +41,13 @@ def config_changed():
     status_set('blocked', 'Waiting for configuration')
 
 
+@when('config.changed')
+@when_not('sshproxy.configured')
+def invalid_credentials():
+    status_set('blocked', 'Waiting for SSH credentials.')
+    pass
+
+
 def is_ping():
     if cfg['mode'] == 'ping':
         return True