Implement stack event list --follow

This adds a --follow option which is similar to the --wait logging
behaviour in changes like I72421c1adf9220e3440179fec672f49803a6cde2
except that --follow doesn't exit until the user does ctrl-c.

This change also includes:
- always sort events ascending for all formatters - the newest events
  should always be at the bottom of the screen as they are generally the
  most interesting
- get_event marker handling tolerates the marker not being in the event
  list. --follow was triggering this, but ignoring the marker in this
  case has not lead to events being printed more than once

Change-Id: Ie0964918fc1d05e7e18aa39ceea6d4777deeb87e
Blueprint: heat-support-python-openstackclient

1 files changed, 5 insertions, 2 deletions

diff --git a/heatclient/common/event_utils.py b/heatclient/common/event_utils.py
index 3e6b197..1b8b179 100644
--- a/heatclient/common/event_utils.py
+++ b/heatclient/common/event_utils.py
@@ -75,8 +75,11 @@ def get_events(hc, stack_id, event_args, nested_depth=0,
 
         # Slice the list if marker is specified
         if marker:
-            marker_index = [e.id for e in events].index(marker)
-            events = events[marker_index:]
+            try:
+                marker_index = [e.id for e in events].index(marker)
+                events = events[marker_index:]
+            except ValueError:
+                pass
 
         # Slice the list if limit is specified
         if limit: