This PR adds a new `--beacon.checkpoint.file` config flag to geth and
blsync which specifies a checkpoint import/export file. If a file with
an existing checkpoint is specified, it is used for initialization
instead of the hardcoded one (except when `--beacon.checkpoint` is also
specified simultaneously). Whenever the client encounters a new valid
finality update with a suitable finalized beacon block root at an epoch
boundary, it saves the block root in hex format to the checkpoint file.
This updates the blsync base types for the Electra fork. I've been
testing, and it doesn't seem to make blsync fully work on Electra. But
I'd still like to get this in to make some progress.
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Co-authored-by: Zsolt Felfoldi <zsfelfoldi@gmail.com>
This PR moves chain config related code (config file processing, fork
logic, network defaults) from `beacon/types` and `beacon/blsync` into
`beacon/params` while the command line flag logic of the chain config is
moved into `cmd/utils`, thereby removing the cli dependencies from
package `beacon` and its sub-packages.
Here we add a beacon chain light client for use by geth.
Geth can now be configured to run against a beacon chain API endpoint,
without pointing a CL to it. To set this up, use the `--beacon.api` flag. Information
provided by the beacon chain is verified, i.e. geth does not blindly trust the beacon
API endpoint in this mode. The root of trust are the beacon chain 'sync committees'.
The configured beacon API endpoint must provide light client data. At this time, only
Lodestar and Nimbus provide the necessary APIs.
There is also a standalone tool, cmd/blsync, which uses the beacon chain light client
to drive any EL implementation via its engine API.
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Co-authored-by: Felix Lange <fjl@twurst.com>
