This PR introduces a new config field SyncFromCheckpoint for light client.
In some special scenarios, it's required to start synchronization from some
arbitrary checkpoint or even from the scratch. So this PR offers this
flexibility to users so that the synchronization start point can be configured.
There are two relevant configs: SyncFromCheckpoint and Checkpoint.
- If the SyncFromCheckpoint is true, the light client will try to sync from the
specified checkpoint.
- If the Checkpoint is not configured, then the light client will sync from the
scratch(from the latest header if the database is not empty)
Additional notes: these two configs are not visible in the CLI flags but only
accessable in the config file.
Example Usage:
[Eth]
SyncFromCheckpoint = true
[Eth.Checkpoint]
SectionIndex = 100
SectionHead = "0xabc"
CHTRoot = "0xabc"
BloomRoot = "0xabc"
PS. Historical checkpoint can be retrieved from the synced full node or light
client via les_getCheckpoint API.
* les: move the checkpoint oracle into its own package
It's first step of refactor LES package. LES package
basically can be divided into LES client and LES server.
However both sides will use checkpoint package for
status retrieval and verification. So this PR moves
checkpoint oracle into a separate package
* les: address comments
There is no need to depend on the old context package now that the
minimum Go version is 1.7. The move to "context" eliminates our weird
vendoring setup. Some vendored code still uses golang.org/x/net/context
and it is now vendored in the normal way.
This change triggered new vet checks around context.WithTimeout which
didn't fire with golang.org/x/net/context.
