Stop/remove existing docker container if the specified tag is different

Fixes #8278

library/cloud/docker

@@ -742,6 +742,7 @@ def main():
         state = module.params.get('state')
         count = int(module.params.get('count'))
         name = module.params.get('name')
+        image = module.params.get('image')
 
         if count < 0:
             module.fail_json(msg="Count must be greater than zero")
@@ -760,12 +761,31 @@ def main():
         if state in [ "running", "present" ]:
 
             # make sure a container with `name` exists, if not create and start it
-            if name and "/" + name not in map(lambda x: x.get('Name'), deployed_containers):
-                containers = manager.create_containers(1)
-                if state == "present": #otherwise it get (re)started later anyways..
-                  manager.start_containers(containers)
-                  running_containers = manager.get_running_containers()
-                deployed_containers = manager.get_deployed_containers()
+            if name:
+                # first determine if a container with this name exists
+                existing_container = None
+                for deployed_container in deployed_containers:
+                    if deployed_container.get('Name') == '/%s' % name:
+                        existing_container = deployed_container
+                        break
+
+                # the named container is running, but with a
+                # different image or tag, so we stop it first
+                if existing_container and existing_container.get('Config', dict()).get('Image') != image:
+                    manager.stop_containers([existing_container])
+                    manager.remove_containers([existing_container])
+                    running_containers = manager.get_running_containers()
+                    deployed_containers = manager.get_deployed_containers()
+                    existing_container = None
+
+                # if the container isn't running (or if we stopped the
+                # old version above), create and (maybe) start it up now
+                if not existing_container:
+                    containers = manager.create_containers(1)
+                    if state == "present": # otherwise it get (re)started later anyways..
+                        manager.start_containers(containers)
+                        running_containers = manager.get_running_containers()
+                    deployed_containers = manager.get_deployed_containers()
 
             if state == "running":
                 # make sure a container with `name` is running