Allow Empty Label Values for Containers

[mcrosson]

Bug description

When deploying a container you cannot specify labels without an empty value. If you don't specify a value they are silently dropped from container creation and cannot be added via the web ui.

Expected behavior
Allow empty/null values for labels set on containers. This is valid per the docker spec and some utilities use labels with empty labels to help with auto-discovery

Steps to reproduce the issue:

Steps to reproduce the behavior:
Deploy a container with a label and no value specified

Technical details:

• Portainer version: 1.20.0
• Docker version (managed by Portainer):
  Docker version 18.09.0, build 4d60db4
• Platform (windows/linux): linux
• Command used to start Portainer (docker run -p 9000:9000 portainer/portainer):
  docker run
  --name portainer
  --restart unless-stopped
  --net docker-private
  --ip 172.30.30.30
  -p 9000:9000
  -e TZ=UTC
  -v /var/portainer:/data
  -v /var/run/docker.sock:/var/run/docker.sock
  portainer
• Browser:

Additional context
Add any other context about the problem here.

[mcrosson]

@deviantony If you'd like to point me in the right direction I can take a shot at a small code change + PR

[deviantony]

Here's an entrypoint for network creation for example: https://github.com/portainer/portainer/blob/develop/app/docker/views/networks/create/createNetworkController.js#L86

[mcrosson]

@deviantony Quick question

Where is the underlying code for things like Container.get({ id: id }).$promise in docker/services/containerService.js I can't seem to connect one of the dots here.

Edit

Looks like api/http/proxy/response.go has extractJSONField and it's somehow eating empty labels.

If the jsonObject returned for a key is empty string will it be assigned nill instead of empty string?

[deviantony]

Hi @mcrosson

Regarding your first question you can usually find these in the rest/ folder of the corresponding module.

Backend should not remove empty labels, I'll check that.

[mcrosson]

@deviantony Thanks!

I did open a PR for the rest of the empty label updates for the container side. The only thing that I ran into is the extractJSONField bit during my testing. Outside of that the PR should be good to go.

[deviantony]

Closed via #2655