Normally, running LC and DAG sync at same time is fine, but on tiny
devnet where some peer may not support the LC data, we can end up in
situation where peer gets disconnected when DAG is in sync, because
DAG sync never uses any req/resp on local devnet (perfect nw conditions)
so the LC sync over minutes removes the peer as sync is stuck.
We don't need to actively sync LC from network if DAG is already synced,
preventing this specific low peer devnet issue (there are others still).
LC is still locally updated when DAG finalized checkpoint advances.
Bellatrix light client data does not contain the EL block hash, so we
had to follow blocks gossip to learn the EL `block_hash` of such blocks.
Now that Bellatrix is obsolete, we can simplify EL syncing logic under
light client scenarios. Bellatrix light client data can still be used
to advance the light client sync itself, but will no longer result in
`engine_forkchoiceUpdated` calls until the sync reaches Capella. This
also frees up some memory as we no longer have to retain blocks.
In nim-web3 all std.Option are replaced by results.Opt. The same goes in nim-eth, with additional fields name changes and GasInt changed from int64 to uint64.
Finish the rename started in #4809 to have a consistent naming.
`ExecutionPayloadHash` suggests hash over payload instead of block.
`BlockHash` is also the canonical name in engine API.
Directly initialize `ForkedLightClientObj` instead of separately first
setting the `kind` (initializing everything to zero) and then assigning
the forky data after that.
For symmetry with `forkyState` when using `withState`, and to avoid
problems with shadowing of `blck` when using `withBlck` in `template`,
also rename the injected `blck` to `forkyBlck`.
- https://github.com/nim-lang/Nim/issues/22698
Just the variable, not yet `lcDataForkAtStateFork` / `atStateFork`.
- Shorten comment in `light_client.nim` to keep line width
- Do not rename `stateFork` mention in `runProposalForkchoiceUpdated`.
- Do not rename `stateFork` in `getStateField(dag.headState, fork)`
Rest is just a mechanical mass replace
* Support for driving multiple EL nodes from a single Nimbus BN
Full list of changes:
* Eth1Monitor has been renamed to ELManager to match its current
responsibilities better.
* The ELManager is no longer optional in the code (it won't have
a nil value under any circumstances).
* The support for subscribing for headers was removed as it only
worked with WebSockets and contributed significant complexity
while bringing only a very minor advantage.
* The `--web3-url` parameter has been deprecated in favor of a
new `--el` parameter. The new parameter has a reasonable default
value and supports specifying a different JWT for each connection.
Each connection can also be configured with a different set of
responsibilities (e.g. download deposits, validate blocks and/or
produce blocks). On the command-line, these properties can be
configured through URL properties stored in the #anchor part of
the URL. In TOML files, they come with a very natural syntax
(althrough the URL scheme is also supported).
* The previously scattered EL-related state and logic is now moved
to `eth1_monitor.nim` (this module will be renamed to `el_manager.nim`
in a follow-up commit). State is assigned properly either to the
`ELManager` or the to individual `ELConnection` objects where
appropriate.
The ELManager executes all Engine API requests against all attached
EL nodes, in parallel. It compares their results and if there is a
disagreement regarding the validity of a certain payload, this is
detected and the beacon node is protected from publishing a block
with a potential execution layer consensus bug in it.
The BN provides metrics per EL node for the number of successful or
failed requests for each type Engine API requests. If an EL node
goes offline and connectivity is resoted later, we report the
problem and the remedy in edge-triggered fashion.
* More progress towards implementing Deneb block production in the VC
and comparing the value of blocks produced by the EL and the builder
API.
* Adds a Makefile target for the zhejiang testnet
When running `nimbus_light_client`, we persist the latest header from
`LightClientStore.finalized_header` in a database across restarts.
Because the data format is derived from the latest `LightClientStore`,
this could lead to data being persisted in pre-release formats.
To enable us to test later `LightClientStore` versions on devnets,
transition to a `ForkedLightClientStore` internally that is only
migrated to newer forks on-demand (instead of starting at latest).
Distinguish between those code locations that need to be updated on each
light client data format change, and those others that should generally
be fine, as long as a valid light client object is processed.
The former are tagged with static assert for `LightClientDataFork.high`.
The latter are changed to `lcDataFork > LightClientDataFork.None` to
indicate that they depend only on presence of any valid object.
Also bundled a few minor cleanups and fixes.
Also add `Forky` type for `LightClientStore` and minor fixes / cleanups.
The light client data structures were changed to accommodate additional
fields in future forks (e.g., to also hold execution data).
There is a minor change to the JSON serialization, where the `header`
properties are now nested inside a `LightClientHeader`.
The SSZ serialization remains compatible.
See https://github.com/ethereum/consensus-specs/pull/3190
and https://github.com/ethereum/beacon-APIs/pull/287
The optimistic candidate block check that only imports a new block into
the EL client if its parent block also had execution enabled is not
needed anymore, as mainnet has merged and the attack period is over.
When the BN-embedded LC makes sync progress, pass the corresponding
execution block hash to the EL via `engine_forkchoiceUpdatedV1`.
This allows the EL to sync to wall slot while the chain DAG is behind.
Renamed `--light-client` to `--sync-light-client` for clarity, and
`--light-client-trusted-block-root` to `--trusted-block-root` for
consistency with `nimbus_light_client`.
Note that this does not work well in practice at this time:
- Geth sticks to the optimistic sync:
"Ignoring payload while snap syncing" (when passing the LC head)
"Forkchoice requested unknown head" (when updating to LC head)
- Nethermind syncs to LC head but does not report ancestors as VALID,
so the main forward sync is still stuck in optimistic mode:
"Pre-pivot block, ignored and returned Syncing"
To aid EL client teams in fixing those issues, having this available
as a hidden option is still useful.
The optimistic sync spec was updated since the LC based optsync module
was introduced. It is no longer necessary to wait for the justified
checkpoint to have execution enabled; instead, any block is okay to be
optimistically imported to the EL client, as long as its parent block
has execution enabled. Complex syncing logic has been removed, and the
LC optsync module will now follow gossip directly, reducing the latency
when using this module. Note that because this is now based on gossip
instead of using sync manager / request manager, that individual blocks
may be missed. However, EL clients should recover from this by fetching
missing blocks themselves.
* Use final `v1` version for light client protocols
* Unhide LC data collection options
* Default enable LC data serving
* rm unneeded import
* Connect to EL on startup
* Add docs for LC based EL sync
The light client sync protocol employs heuristics to ensure it does not
become stuck during non-finality or low sync committee participation.
These can enable use cases that prefer availability of recent data
over security. For our syncing use case, though, security is preferred.
An option is added to light client processor to configure this tradeoff.
For consistency with other options, use a common prefix for light client
data configuration options.
* `--serve-light-client-data` --> `--light-client-data-serve`
* `--import-light-client-data` --> `--light-client-data-import-mode`
No deprecation of the old identifiers as they were only sparingly used
and all usage can be easily updated without interferance.
When launched with `--light-client-enable` the latest blocks are fetched
and optimistic candidate blocks are passed to a callback (log for now).
This helps accelerate syncing in the future (optimistic sync).
Adds a `LightClient` instance to the beacon node as preparation to
accelerate syncing in the future (optimistic sync).
- `--light-client-enable` turns on the feature
- `--light-client-trusted-block-root` configures block to start from
If no block root is configured, light client tracks DAG `finalizedHead`.
Etan Kissling
Eugene Kabanov
tersec
Etan Kissling
andri lim
Jacek Sieka
zah
Miran