Provide hook point in cfn_delete after confirm but before DeleteStack…

… call

This is used by bootstrap-salt to delete a file that it manages in an s3
bucket that would otherwise stop the stack from deleting.

CHANGELOG.md

@@ -1,3 +1,11 @@
+## Version 0.5.x
+
+* Provide hook point in cfn_delete fab task after confirm but before
+  DeleteStack call.
+
+  This is used by bootstrap-salt to remove a file that it places and manages
+  in an S3 bucket so that the stack can be cleanly deleted.
+
 ## Version 0.5.6
 * Automaticly generate the RDS identifier
 

bootstrap_cfn/fab_tasks.py

@@ -282,7 +282,7 @@ def get_connection(klass):
 
 
 @task
-def cfn_delete(force=False):
+def cfn_delete(force=False, pre_delete_callbacks=None):
     """
     Delete the AWS Cloudformation stack
 
@@ -291,6 +291,10 @@ def cfn_delete(force=False):
     Args:
         force(bool): True to destroy the stack without any further
             input, False to require confirmation before deletion
+        pre_delete_callbacks(list of callables): callable to invoke before
+            trying to run the DeleteStack call. Each callback is called with
+            kwargs of ``stack_name``, and ``config``. (Python only, not setable from
+            command line)
     """
     if not force:
         x = raw_input("Are you really sure you want to blow away the whole stack!? (y/n)\n")
@@ -302,6 +306,10 @@ def cfn_delete(force=False):
     cfn.delete(stack_name)
     print green("\nSTACK {0} DELETING...\n").format(stack_name)
 
+    if pre_delete_callbacks is not None:
+        for callback in pre_delete_callbacks:
+            callback(stack_name=stack_name, config=cfn_config)
+
     if not env.blocking:
         print 'Running in non blocking mode. Exiting.'
         sys.exit(0)