Addresses #8218
A simplified version of #8241 for the initial release.
I've tried to minimise the logic change in this PR, although introducing the `NodeCustodyType` enum still result in quite a bit a of diff, but the actual logic change in `CustodyContext` is quite small.
The main changes are in the `CustdoyContext` struct
* ~~combining `validator_custody_count` and `current_is_supernode` fields into a single `custody_group_count_at_head` field. We persist the cgc of the initial cli values into the `custody_group_count_at_head` field and only allow for increase (same behaviour as before).~~
* I noticed the above approach caused a backward compatibility issue, I've [made a fix](15569bc085) and changed the approach slightly (which was actually what I had originally in mind):
* when initialising, only override the `validator_custody_count` value if either flag `--supernode` or `--semi-supernode` is used; otherwise leave it as the existing default `0`. Most other logic remains unchanged.
All existing validator custody unit tests are still all passing, and I've added additional tests to cover semi-supernode, and restoring `CustodyContext` from disk.
Note: I've added a `WARN` if the user attempts to switch to a `--semi-supernode` or `--supernode` - this currently has no effect, but once @eserilev column backfill is merged, we should be able to support this quite easily.
Things to test
- [x] cgc in metadata / enr
- [x] cgc in metrics
- [x] subscribed subnets
- [x] getBlobs endpoint
Co-Authored-By: Jimmy Chen <jchen.tc@gmail.com>
N/A
Persist the epoch -> cgc values. This is to ensure that `ValidatorRegistrations::latest_validator_custody_requirement` always returns a `Some` value post restart assuming the `epoch_validator_custody_requirements` map has been updated in the previous runs.
Resolves#6767
This PR implements a basic version of validator custody.
- It introduces a new `CustodyContext` object which contains info regarding number of validators attached to a node and the custody count they contribute to the cgc.
- The `CustodyContext` is added in the da_checker and has methods for returning the current cgc and the number of columns to sample at head. Note that the logic for returning the cgc existed previously in the network globals.
- To estimate the number of validators attached, we use the `beacon_committee_subscriptions` endpoint. This might overestimate the number of validators actually publishing attestations from the node in the case of multi BN setups. We could also potentially use the `publish_attestations` endpoint to get a more conservative estimate at a later point.
- Anytime there's a change in the `custody_group_count` due to addition/removal of validators, the custody context should send an event on a broadcast channnel. The only subscriber for the channel exists in the network service which simply subscribes to more subnets. There can be additional subscribers in sync that will start a backfill once the cgc changes.
TODO
- [ ] **NOT REQUIRED:** Currently, the logic only handles an increase in validator count and does not handle a decrease. We should ideally unsubscribe from subnets when the cgc has decreased.
- [ ] **NOT REQUIRED:** Add a service in the `CustodyContext` that emits an event once `MIN_EPOCHS_FOR_BLOB_SIDECARS_REQUESTS ` passes after updating the current cgc. This event should be picked up by a subscriber which updates the enr and metadata.
- [x] Add more tests
