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.
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.
Whether new blocks/attestations/etc are produced internally or received
via REST, their journey through the node is the same - to ensure that
they get the same treatment (logging, metrics, processing), this PR
moves the routing to a dedicated module and fixes several small
differences that existed before.
* `xxxValidator` -> `processMessageName` - the processor also was adding
messages to pools, so we want the name to reflect that action
* add missing "sent" metrics for some messages
* document ignore policy better - already-seen messages are not actaully
rebroadcast by libp2p
* skip redundant signature checks for internal validators consistently
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`.
Introduces a new library for syncing using libp2p based light client
sync protocol, and adds a new `nimbus_light_client` executable that uses
this library for syncing. The new executable emits log messages when
new beacon block headers are received, and is integrated into testing.
Etan Kissling
Miran
Jacek Sieka