Show human readable value for mem and cpu limits

README.md

@@ -48,7 +48,7 @@ Just like on [Binder](https://mybinder.org), new environments can be added by cl
 
 Once ready, the environments can be selected from the JupyterHub spawn page:
 
-![select-env](https://user-images.githubusercontent.com/591645/80963143-abb9fa80-8e0e-11ea-94c1-ddd7962f7283.png)
+![select-env](https://user-images.githubusercontent.com/591645/81152248-10e22d00-8f82-11ea-9b5f-5831d8f7d085.png)
 
 ### Extra documentation
 

tljh_repo2docker/__init__.py

@@ -6,6 +6,7 @@
 from dockerspawner import DockerSpawner
 from jinja2 import Environment, BaseLoader
 from jupyter_client.localinterfaces import public_ips
+from jupyterhub.traitlets import ByteSpecification
 from tljh.hooks import hookimpl
 from tljh.configurer import load_config, CONFIG_FILE
 from tornado.ioloop import IOLoop
@@ -109,10 +110,23 @@ async def get_options_form(self):
         Override the default form to handle the case when there is only one image.
         """
         images = await self.list_images()
+
+        # make default limits human readable
+        default_mem_limit = self.mem_limit
+        if isinstance(default_mem_limit, (float, int)):
+            # default memory unit is in GB
+            default_mem_limit /= ByteSpecification.UNIT_SUFFIXES['G']
+            if float(default_mem_limit).is_integer():
+                default_mem_limit = int(default_mem_limit)
+
+        default_cpu_limit = self.cpu_limit
+        if default_cpu_limit and float(default_cpu_limit).is_integer():
+            default_cpu_limit = int(default_cpu_limit)
+
         # add memory and cpu limits
         for image in images:
-            image['mem_limit'] = image['mem_limit'] or self.mem_limit
-            image['cpu_limit'] = image['cpu_limit'] or self.cpu_limit
+            image['mem_limit'] = image['mem_limit'] or default_mem_limit
+            image['cpu_limit'] = image['cpu_limit'] or default_cpu_limit
 
         image_form_template = Environment(loader=BaseLoader).from_string(self.image_form_template)
         return image_form_template.render(image_list=images)