Description

I tried to run dshackle in front of a geth execution client for the etherum testnet merge-devnet-2 with the following config:

version: v1
port: 2449
tls:
  enabled: false

proxy:
  host: 0.0.0.0
  port: 2450
  routes:
    - id: eth
      blockchain: ethereum

cluster:
  defaults:
    - chains:
        - ethereum
  upstreams:
    - id: geth
      chain: ethereum
      connection:
        ethereum:
          rpc:
            url: "http://localhost:8550"

Dshackle fails to update its height as shown by the logs:

2021-03-12 20:10:35.650 | INFO  |          Multistream | State of ETH: height=21611, status=[UNAVAILABLE/1], lag=[0], weak=[geth]
2021-03-12 20:10:50.641 | INFO  |          Multistream | State of ETH: height=21611, status=[OK/1], lag=[0], weak=[]
2021-03-12 20:11:05.642 | INFO  |          Multistream | State of ETH: height=21611, status=[OK/1], lag=[0], weak=[]
2021-03-12 20:11:35.642 | INFO  |          Multistream | State of ETH: height=21611, status=[OK/1], lag=[0], weak=[]
2021-03-12 20:12:05.642 | INFO  |          Multistream | State of ETH: height=21611, status=[OK/1], lag=[0], weak=[]

Dshackle seems to find a height during the startup process and never updates it even though the chain progresses.
So when i request for the eth_getBlockByNumber latest block, i always get the one shown in the logs as height. However, manually requesting for a newer block works fine.

However this behaviour isn't seen on mainnet, i aimed my Dshackle towards a mainnet node and it updates/works fine.

This leads me to believe its an issue with the change in behaviour introduced by the merge testnets.

How to reproduce:

• Sync a merge devnet Execution client(eth1)+Consensus client(eth2) pair(both are needed for the merge testnet): instructions
• Configure Dshackle to the Execution client RPC port
• Test the call eth_getBlockByNumber with latest, multiple times with some gap in between

Potential theories:

• It seems like Dshackle has some logic around Total difficulty to check if a block is to be updated, merge testnets after "the merge" will have the same difficulty throughout - meaning Dshackle might not update its understanding of the latest block
• ??

Other debug steps I tried:

• I ran a json rpc snooper to capture all req/responses and compared them between the merge and mainnet nodes. The JSON bodies are unchanged. Dshackle does seem to be calling eth_blockNumber and receiving a later block than shown by height, it is also using this new block in the subsequent eth_getBlockByNumber call - however it doesn't seem to be updating its view afterwards.

Note:

• The merge-devnets are re-launched every week, I'd be happy to point to newer instructions/configs or even keep this one around.
• I'm unsure if the maintainers are aware of the merge changes, I'd be happy to answer questions/forward to more knowledgeable people if needed.
• Thank you so much for looking at my issue :)