From 7032f4bb1ee4a3012084ef2cce6b543761f0a137 Mon Sep 17 00:00:00 2001
From: David Wittman <david@wittman.com>
Date: Thu, 25 Sep 2014 12:31:31 -0500
Subject: [PATCH] Idempotency for LXC cloning

Previously, clone operations where the new container already exists were
reporting as failed. This commit modifies that behavior so that if the
new container exists, it returns the facts for that container instead of
failing.

To facilitate these changes, a _container_exists method was added which
returns True or False based on whether or not the container name is in
the output from self._list().

I also made a few fixes in the documentation by removing trailing spaces
and fixing a typo in the state on line 222.
---
 rpc_deployment/library/lxc | 58 ++++++++++++++++++++++++--------------
 1 file changed, 37 insertions(+), 21 deletions(-)
 mode change 100755 => 100644 rpc_deployment/library/lxc

diff --git a/rpc_deployment/library/lxc b/rpc_deployment/library/lxc
old mode 100755
new mode 100644
index 3aca4efb1c..e455da1486
--- a/rpc_deployment/library/lxc
+++ b/rpc_deployment/library/lxc
@@ -40,12 +40,12 @@ options:
           - Name of a container.
         required: false
     return_code:
-        description: 
-          - Allow for return Codes other than 0 when executing commands. 
+        description:
+          - Allow for return Codes other than 0 when executing commands.
             This is a comma separated list of acceptable return codes.
         default: 0
     backingstore:
-        description: 
+        description:
           - Options 'dir', 'lvm', 'loop', 'btrfs', 'best'. The default is
             'none'.
         required: false
@@ -96,11 +96,11 @@ options:
           - Create zfs under given zfsroot (Default tank/lxc).
         required: false
     container_command:
-        description: 
+        description:
           - Run a command in a container. Only used in the "attach" operation.
         required: false
     return_facts:
-        description: 
+        description:
           - Return stdout after an attach command. Only used in the "attach"
             operation.
         required: false
@@ -219,7 +219,7 @@ container_config_options:
 - lxc: orig=test-container
        new=test-container-new
        command=clone
-       state=started
+       state=running
 
 # Destroy a container.
 - lxc: name=test-container
@@ -546,7 +546,7 @@ class LxcManagement(object):
 
         rc, return_data, err = self._run_command(build_command)
         if rc not in self.rc:
-            msg = 'Failed to get container Information.'
+            msg = 'Failed to get container Information'
             self.failure(err, rc, msg)
 
         ip_count = 0
@@ -561,6 +561,19 @@ class LxcManagement(object):
         else:
             return cstate
 
+    def _container_exists(self, name, variables_dict):
+        """Return True or False based on whether or not the container exists
+
+        :param name: ``str``    name of the container
+        """
+        containers = self._list(variables_dict=variables_dict)
+
+        for container in containers.splitlines():
+            if container == name:
+                return True
+
+        return False
+
     @staticmethod
     def _construct_command(build_list):
         """Return a string from a command and build list.
@@ -679,21 +692,19 @@ class LxcManagement(object):
         name = variables_dict.pop('name')
         state = variables_dict.pop('state', 'running')
 
-        containers = self._list(variables_dict=variables_dict)
-        for container in containers.splitlines():
-            if container == name:
-                container_info = self._get_container_info(
-                    name=name, variables_dict=variables_dict
-                )
-                return self._lxc_facts(facts={name: container_info})
+        if self._container_exists(name, variables_dict):
+            container_info = self._get_container_info(
+                name=name, variables_dict=variables_dict
+            )
         else:
-            created_container_info = self._create(name, state, variables_dict)
-            return self._lxc_facts(facts={name: created_container_info})
+            container_info = self._create(name, state, variables_dict)
+
+        return self._lxc_facts(facts={name: container_info})
 
     def _destroy(self, name):
         """Destroy an LXC container.
 
-        :param name: ``str`  Name of the container to destroy
+        :param name: ``str``  Name of the container to destroy
         """
         build_command = [
             self.module.get_bin_path('lxc-destroy', True),
@@ -720,10 +731,8 @@ class LxcManagement(object):
         variables_dict = self._get_vars(variables, required=['name'])
         name = variables_dict.pop('name')
 
-        containers = self._list(variables_dict=variables_dict)
-        for container in containers.splitlines():
-            if container == name:
-                self._destroy(name=name)
+        if self._container_exists(name, variables_dict):
+            self._destroy(name=name)
 
     def _local_clone(self, orig, new, variables_dict):
         """Clone a local container.
@@ -788,6 +797,13 @@ class LxcManagement(object):
         orig = variables_dict.pop('orig')
         new = variables_dict.pop('new')
 
+        # Check to see if new container already exists
+        if self._container_exists(new, variables_dict):
+            new_container_info = self._get_container_info(
+                name=new, variables_dict=variables_dict
+            )
+            return self._lxc_facts(facts={new: new_container_info})
+
         container_data = self._get_container_info(
             name=orig, variables_dict=variables_dict
         )