Add --semi-supernode support (#8254)

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>

beacon_node/beacon_chain/tests/block_verification.rs

@@ -4,6 +4,7 @@ use beacon_chain::block_verification_types::{AsBlock, ExecutedBlock, RpcBlock};
 use beacon_chain::data_column_verification::CustodyDataColumn;
 use beacon_chain::{
     AvailabilityProcessingStatus, BeaconChain, BeaconChainTypes, ExecutionPendingBlock,
+    custody_context::NodeCustodyType,
     test_utils::{
         AttestationStrategy, BeaconChainHarness, BlockStrategy, EphemeralHarnessType, test_spec,
     },
@@ -45,7 +46,7 @@ async fn get_chain_segment() -> (Vec<BeaconSnapshot<E>>, Vec<Option<DataSidecars
     // The assumption that you can re-import a block based on what you have in your DB
     // is no longer true, as fullnodes stores less than what they sample.
     // We use a supernode here to build a chain segment.
-    let harness = get_harness(VALIDATOR_COUNT, true);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Supernode);
 
     harness
         .extend_chain(
@@ -106,7 +107,7 @@ async fn get_chain_segment() -> (Vec<BeaconSnapshot<E>>, Vec<Option<DataSidecars
 
 fn get_harness(
     validator_count: usize,
-    supernode: bool,
+    node_custody_type: NodeCustodyType,
 ) -> BeaconChainHarness<EphemeralHarnessType<E>> {
     let harness = BeaconChainHarness::builder(MainnetEthSpec)
         .default_spec()
@@ -115,7 +116,7 @@ fn get_harness(
             ..ChainConfig::default()
         })
         .keypairs(KEYPAIRS[0..validator_count].to_vec())
-        .import_all_data_columns(supernode)
+        .node_custody_type(node_custody_type)
         .fresh_ephemeral_store()
         .mock_execution_layer()
         .build();
@@ -259,7 +260,7 @@ fn update_data_column_signed_header<E: EthSpec>(
 
 #[tokio::test]
 async fn chain_segment_full_segment() {
-    let harness = get_harness(VALIDATOR_COUNT, false);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
     let (chain_segment, chain_segment_blobs) = get_chain_segment().await;
     let blocks: Vec<RpcBlock<E>> = chain_segment_blocks(&chain_segment, &chain_segment_blobs)
         .into_iter()
@@ -297,7 +298,7 @@ async fn chain_segment_full_segment() {
 #[tokio::test]
 async fn chain_segment_varying_chunk_size() {
     for chunk_size in &[1, 2, 3, 5, 31, 32, 33, 42] {
-        let harness = get_harness(VALIDATOR_COUNT, false);
+        let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
         let (chain_segment, chain_segment_blobs) = get_chain_segment().await;
         let blocks: Vec<RpcBlock<E>> = chain_segment_blocks(&chain_segment, &chain_segment_blobs)
             .into_iter()
@@ -329,7 +330,7 @@ async fn chain_segment_varying_chunk_size() {
 
 #[tokio::test]
 async fn chain_segment_non_linear_parent_roots() {
-    let harness = get_harness(VALIDATOR_COUNT, false);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
     let (chain_segment, chain_segment_blobs) = get_chain_segment().await;
 
     harness
@@ -386,7 +387,7 @@ async fn chain_segment_non_linear_parent_roots() {
 
 #[tokio::test]
 async fn chain_segment_non_linear_slots() {
-    let harness = get_harness(VALIDATOR_COUNT, false);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
     let (chain_segment, chain_segment_blobs) = get_chain_segment().await;
     harness
         .chain
@@ -528,7 +529,7 @@ async fn assert_invalid_signature(
 async fn get_invalid_sigs_harness(
     chain_segment: &[BeaconSnapshot<E>],
 ) -> BeaconChainHarness<EphemeralHarnessType<E>> {
-    let harness = get_harness(VALIDATOR_COUNT, false);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
     harness
         .chain
         .slot_clock
@@ -986,7 +987,7 @@ fn unwrap_err<T, U>(result: Result<T, U>) -> U {
 
 #[tokio::test]
 async fn block_gossip_verification() {
-    let harness = get_harness(VALIDATOR_COUNT, false);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
     let (chain_segment, chain_segment_blobs) = get_chain_segment().await;
 
     let block_index = CHAIN_SEGMENT_LENGTH - 2;
@@ -1389,7 +1390,7 @@ async fn verify_block_for_gossip_slashing_detection() {
 
 #[tokio::test]
 async fn verify_block_for_gossip_doppelganger_detection() {
-    let harness = get_harness(VALIDATOR_COUNT, false);
+    let harness = get_harness(VALIDATOR_COUNT, NodeCustodyType::Fullnode);
 
     let state = harness.get_current_state();
     let ((block, _), _) = harness.make_block(state.clone(), Slot::new(1)).await;