Allow setting the tag independently

README.md

@@ -65,6 +65,7 @@ of the container's parameters.
       --pull                Docker pull the image before re-running the container
       --image IMAGE         Image to use in place of the original
       --port PORT, -p PORT  Additional port to expose
+      --tag TAG             Image tag (version) to use
 
 ## What's not done yet
 

docker-rerun

@@ -228,6 +228,18 @@ def modify_port_add(parser=None, args=None, container=None):
         container.args.extend(['-p=%s' % port for port in args.port])
 
 
+def modify_tag(parser=None, args=None, container=None):
+    """Allows the tag (version) to be updated."""
+    if parser:
+        parser.add_argument('--tag',
+                            help='Image tag (version) to use')
+    elif args.tag:
+        # Get rid of any existing digest or tag
+        image = container.image.replace('@', ':')
+        image = image.split(':')[0]
+        container.image = '%s:%s' % (image, args.tag)
+
+
 def functions():
     """Lists all functions defined in this module.
 

test.py

@@ -66,6 +66,10 @@ def test_modifiers():
            ['docker', 'run', '--name=test123', '-d', 'hello-world'],
            ['--port', '123:456', '-p', '80'],
            ['docker', 'run', '--name=test123', '-d', '-p=123:456', '-p=80', 'hello-world'])
+    yield (check,
+           ['docker', 'run', '--name=test123', '-d', 'hello-world'],
+           ['--tag', 'latest'],
+           ['docker', 'run', '--name=test123', '-d', 'hello-world:latest'])
 
 
 @with_setup(setup_each, teardown_each)