[DO-NOT-MERGE] Promote slice configuration to its own netcfg subject

[ccascone]

This PR is not functional and should not be merged.

We propose an alternative schema to the one introduced in #454 and #457. Instead of being nested inside an app config, slices get configured using their own netcfg event subject. The main benefit is that apps like NetcfgSlicingProvider can listen to events for individual slices, simplifying the diff update logic.

Example netcfg:

{
  "slices": {
    "0": {
      "basic": {
        "name": "Default",
        "tcs": {
          "REAL_TIME": {
            "queueId": 1,
            "isSystemTc": true
          }
        }
      }
    },
    "1": {
      "basic": {
        "name": "P4-UPF",
        "tcs": {
          "CONTROL": {
            "queueId": 2,
            "maxRateBps": "2000000"
          },
          "REAL_TIME": {
            "queueId": 3,
            "maxRateBps": "50000000"
          },
          "ELASTIC": {
            "queueId": 4,
            "gminRateBps": "10000000"
          }
        }
      }
    },
    "2": {
      "basic": {
        "name": "BESS-UPF",
        "tcs": {
          "ELASTIC": {
            "queueId": 5
          }
        }
      }
    }
  }
}

Unfortunately, this approach doesn't work in its current form. For SliceId to be used as a subject class, it needs to be registered in the Kryo serializer of ONOS's DistributedNetworkConfigStore. We cannot make ONOS depend on fabric-tna. The right solution would be to move SliceId and other classes to the ONOS core.

TODO:

• Consider yet another alternative schema where we can get events for individual TCs (to further simplify updates)
• Move SlicingService API classes to ONOS core

[codecov]

Codecov Report

Merging #459 (d36838a) into main (2fccc7d) will increase coverage by 0.17%.
The diff coverage is 50.34%.

@@             Coverage Diff              @@
##               main     #459      +/-   ##
============================================
+ Coverage     66.95%   67.13%   +0.17%     
- Complexity      621      632      +11     
============================================
  Files            63       58       -5     
  Lines          4452     4442      -10     
  Branches        472      480       +8     
============================================
+ Hits           2981     2982       +1     
+ Misses         1235     1212      -23     
- Partials        236      248      +12     

Impacted Files	Coverage Δ
.../java/org/stratumproject/fabric/tna/Constants.java	100.00% <ø> (ø)
.../org/stratumproject/fabric/tna/PipeconfLoader.java	0.00% <0.00%> (ø)
...ratumproject/fabric/tna/behaviour/FabricUtils.java	77.58% <ø> (ø)
...abric/tna/behaviour/pipeliner/FabricPipeliner.java	30.83% <0.00%> (ø)
...aviour/pipeliner/FilteringObjectiveTranslator.java	82.88% <ø> (ø)
...viour/pipeliner/ForwardingObjectiveTranslator.java	74.19% <ø> (ø)
...ject/fabric/tna/slicing/NetcfgSlicingProvider.java	0.00% <0.00%> (ø)
...stratumproject/fabric/tna/slicing/api/SliceId.java	83.33% <ø> (ø)
...project/fabric/tna/slicing/cli/FlowAddCommand.java	0.00% <0.00%> (ø)
...project/fabric/tna/slicing/cli/FlowGetCommand.java	0.00% <0.00%> (ø)
... and 18 more

---

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[pierventre]

Regarding Slicing API in the ONOS core - don't we have already a review from @Wailoks ?

[charlesmcchan]

We agreed to put this on hold during the stand up on 1/24. Will revisit this once we need to support dynamic update / move slicing service to ONOS core.

And to @pierventre 's comment - I believe you referred to this one https://gerrit.onosproject.org/c/onos/+/24932, but it has to be updated too since Carmelo introduced some API changes in this series.

[pierventre]

We agreed to put this on hold during the stand up on 1/24. Will revisit this once we need to support dynamic update / move slicing service to ONOS core.

And to @pierventre 's comment - I believe you referred to this one https://gerrit.onosproject.org/c/onos/+/24932, but it has to be updated too since Carmelo introduced some API changes in this series.

Yup - mine was just a reminder :)