Fix HasResource inverted boolean error

[s4ke]

- What I did

While fixing moby/moby#44378 for named resources in #3082, we inadvertedly broke scheduling for people with discrete resources.

- How I did it

Investigated the code and added more unit tests.

- How to test it

Run the unit tests. Broken behaviour can be reproduced with a setup with gpu_test=5:

moby/moby#44378 (comment)

[s4ke]

I honestly would love to add more unit tests to constraint_enforcer_test.go, but I am unsure about how to test for "no failure". I would appreciate some pointers.

[codecov-commenter]

Codecov Report

Merging #3162 (d67eec8) into master (7eb5046) will increase coverage by 61.80%.
The diff coverage is 100.00%.

Additional details and impacted files

@@             Coverage Diff             @@
##           master    #3162       +/-   ##
===========================================
+ Coverage        0   61.80%   +61.80%     
===========================================
  Files           0      155      +155     
  Lines           0    31139    +31139     
===========================================
+ Hits            0    19244    +19244     
- Misses          0    10341    +10341     
- Partials        0     1554     +1554     

[s4ke]

@dperny PTAL. Kind of embarrasing that I didn't check this last time around. But boolean logic is hard, okay?

[s4ke]

I additionally verified the fix by running a dind version of moby/moby with the fix applied.

root@6a234821266f:/go/src/github.com/docker/docker# docker ps
CONTAINER ID   IMAGE     COMMAND   CREATED   STATUS    PORTS     NAMES
root@6a234821266f:/go/src/github.com/docker/docker# docker ^C
root@6a234821266f:/go/src/github.com/docker/docker# docker network create -d overlay --scope swarm test-network
Error response from daemon: cannot create a swarm scoped network when swarm is not active
root@6a234821266f:/go/src/github.com/docker/docker# docker swarm init
Swarm initialized: current node (o6ek9v8noxrc2n0dgfw5usw3j) is now a manager.

To add a worker to this swarm, run the following command:

    docker swarm join --token SWMTKN-1-39mijudamxqjwwifamr1e7lpe8cjxxrnftkpn31342q91parvd-7g63d3i274dmhx264mkbwbfpo 172.17.0.6:2377

To add a manager to this swarm, run 'docker swarm join-token manager' and follow the instructions.

root@6a234821266f:/go/src/github.com/docker/docker# docker network create -d overlay --scope swarm test-network
zem9t2vf033kkcpa5si9ygukb
root@6a234821266f:/go/src/github.com/docker/docker# docker service create --network test-network --generic-resource "gpu_test=2" --name test-service-2 ubuntu tail -f /dev/n
ull
uhxbdxii0dmbtkfhlqmqhf23d
overall progress: 1 out of 1 tasks 
1/1: running   [==================================================>] 
verify: Service converged 
root@6a234821266f:/go/src/github.com/docker/docker# docker service create --network test-network --generic-resource "gpu_test=4" --name test-service-3 ubuntu tail -f /dev/n
ull
ip5x4qx6meorygcu5plo2a465
overall progress: 0 out of 1 tasks 
1/1: no suitable node (insufficient resources on 1 node) 
Operation continuing in background.
Use `docker service ps ip5x4qx6meorygcu5plo2a465` to check progress.
root@6a234821266f:/go/src/github.com/docker/docker# docker service create --network test-network --generic-resource "gpu_test=3" --name test-service-4 ubuntu tail -f /dev/n
ull
vqxyav44kkyiqriyrdi289vk4
overall progress: 1 out of 1 tasks 
1/1: running   [==================================================>] 
verify: Service converged 
root@6a234821266f:/go/src/github.com/docker/docker# 

[s4ke]

@thaJeztah PTAL - this is blocking people from upgrading to >23.x from 20.x . It fell through last time I fixed something in the same area.

[thaJeztah]

LGTM, thanks!

[thaJeztah]

This will also need a re-vendor in moby/moby 😅

[s4ke]

I will take care of that if you want. The process for vendoring for moby/swarmkit into moby/moby is something that I keep having to make up as I go. Is there documentation that I missed for that?

[thaJeztah]

Within the moby repo, you can edit the vendor.mod and set the latest commit from the swarmkit repository for the dependency; then run hack/vendor.sh (which updates the vendored code), and commit the results 👍

I tend to include a diff link in the description, for others to have an easier way to see what changed, but that's not required.