How to fork mainnet L1 into a devnet?

phroi · August 3, 2023, 2:50am

Hey all

I need to simulate some scenarios with a lock that is already deployed on L1 and that has complex interactions with other locks already deployed.

So basically I need to fork mainnet L1 into a devnet, how should I proceed?

Phroi

xjd · August 3, 2023, 6:36am

Normally, ckb-transaction-dumper will be enough. Then you can run scripts via ckb-debugger.

phroi · August 3, 2023, 11:50am

Honestly I’m a bit confused

Can you make an example of use?

matt.bit · August 3, 2023, 7:12pm

this looks like a decent example

github.com

nervosnetwork/ckb-standalone-debugger/blob/develop/ckb-debugger/examples/mock_tx.md

# Example mock-tx

We can download a transaction from the network and execute it locally. To download a transaction, use [ckb-cli](https://github.com/nervosnetwork/ckb-cli):

```sh
$ ckb-cli --url https://mainnet.ckbapp.dev/rpc mock-tx dump --tx-hash 0x5f0a4162622daa0e50b2cf8f49bc6ece22d1458d96fc12a094d6f074d6adbb55 --output-file mock_tx.json
```

You can execute the lock script or type script in the transaction:

```sh
$ ckb-debugger --tx-file mock_tx.json --cell-index 0 --cell-type input --script-group-type lock

Run result: 0
Total cycles consumed: 1697297(1.6M)
Transfer cycles: 12680(12.4K), running cycles: 1684617(1.6M)
```

The option `--bin` gives ckb-debugger a chance to "replace" the script, We try to replace the running code in the transaction above with a new version of the lock.

This file has been truncated. show original

doitian · August 4, 2023, 3:03am

Do you mean run a devchain using existing mainnet data?

Run a local CKB dev chain using existing testnet/mainnet data

Copy the data directory to a new directory. The following steps will be done in this new directory.
Download the corresponding chain spec file based on testnet or mainnet
1. testnet https://github.com/nervosnetwork/ckb/blob/develop/resource/specs/testnet.toml
2. mainnet https://github.com/nervosnetwork/ckb/blob/develop/resource/specs/mainnet.toml
Initialize dev chain and import testnet or mainnet chain spec, taking mainnet as an example
```
ckb init -c dev --import-spec /path/to/downloaded/mainnet.toml --force
```

Modify the imported specs/dev.toml

[params]
genesis_epoch_length = 1743
# params can add the following options for configuration, keep genesis_epoch_length the same as original file
initial_primary_epoch_reward = 1_917_808_21917808
secondary_epoch_reward = 613_698_63013698
max_block_cycles = 10_000_000_000
cellbase_maturity = 0
primary_epoch_reward_halving_interval = 8760
epoch_duration_target = 14400
# For development and testing purposes only.
# Keep difficulty be permanent if the pow is Dummy. (default: false)
permanent_difficulty_in_dummy = true

# Change pow.func to Dummy
[pow]
func = "Dummy"

Now CKB can be started, need to add parameters -skip-spec-check --overwrite-spec for the first run
```
ckb run --skip-spec-check --overwrite-spec
```

I previously suggesting change the spec name to ckb_dev:

# change name in the first line to ckb_dev
name = "ckb_dev"

However, this will use the softfork and hardfork configurations for dev chain, to follow the mainnet or testnet forks configurations, just keep the original values.

phroi · August 4, 2023, 4:52am

This is the information I was actually asking for, thanks @doitian!!

phroi · August 4, 2023, 5:05am

About this other tool, ckb-debugger, thanks @matt.bit for pointing me out that example, maybe that could have been the response right away!

At the beginning I didn’t understand how to use it because I was believing that it would revalidate the entire transaction. Then again carefully looking at ckb-debugger --help:

--cell-index <cell-index> Index of cell to run

This implies that it only validates the script indicated by the parameters.

Understood this, it was easy to solve my problem with it, thanks @xjd for pointing out ckb-debugger

phroi · August 7, 2023, 10:52am

Hey @doitian, I followed these steps for forking mainnet into devnet and it worked like a charm, thanks!

Now I want to speed up this devnet to test dCKB and NervosDAO interactions, so I followed the steps you previously suggested, but the epoch length doesn’t seem much affected by them. Currently one epoch is more than 16 minutes.

As indicated in your current answer, I didn’t change the genesis_epoch_length. To fully reproduce this issue follow the steps indicated on the Readme.

How should I proceed?

doitian · August 8, 2023, 9:17am

It seems we need a feature to lock the epoch length since a starting epoch for dev environment. Could you post it into the Github repo?

phroi · August 8, 2023, 12:42pm

github.com/nervosnetwork/ckb

Lock the epoch length in a devchain using mainnet data

opened 12:41PM - 08 Aug 23 UTC

phroi

t:enhancement

## Feature Request #### Background Currently I'm working on [rescuing dCKB d…eposits](https://github.com/dckb-rescuer) by writing a new web interface. Given the lack of documentation, it seems impossible to re-deploy correctly those contracts on a brand new devnet. #### Is your feature request related to a problem? Please describe. [Following @doitian instructions](https://talk.nervos.org/t/how-to-fork-mainnet-l1-into-a-devnet/7329/5), I'm running a devchain using existing mainnet data. Now I want to speed up this devnet to test dCKB and NervosDAO interactions, so I followed [the steps previously suggested](https://talk.nervos.org/t/is-there-any-way-to-speed-up-the-blockchain-in-a-way-that-180-epochs-happen-in-a-reasonable-time-frame-in-the-ckb-local-devchain/7163), except for changing the `genesis_epoch_length` as indicated. The issue is the epoch length doesn't seem much affected by them, as currently one epoch is more than 16 minutes. To fully reproduce this issue follow the [steps indicated on the Readme](https://github.com/dckb-rescuer/v1-interface/tree/ed3b384967d24cbbf297ec2a2e41c356bf90668b). #### Describe the solution you'd like [@doitian suggested](https://talk.nervos.org/t/how-to-fork-mainnet-l1-into-a-devnet/7329/9): > It seems we need a feature to lock the epoch length since a starting epoch for dev environment. Keep up the great work 💪 Phroi

orange-xc · August 24, 2023, 7:20am

Can we use capsule/crates/testtool to develop a tool that can setup a node quickly just like anvil Reference

xueyanli · September 11, 2023, 10:50am

If you are using the ckb111+ version,

The first point is that you need to consider the hardfork compatibility configuration. In specs/dev.toml, append the following hardfork configuration
```
[params.hardfork]
ckb2023 = value
```
Usually this value can be set to a number larger than the latest epoch sequence number;

The second point is to consider that locking the epoch length when starting the ckb node in the dev network requires permanent_difficulty_in_dummy = true, and the length of epoch_duration_target is not greater than 14400 and not less than 8. If it cannot be divided by 8, it will be rounded up as an epoch. The maximum number of blocks, the complete configuration is as follows:

# Change the first line name to ckb_dev
name = "ckb_dev"

[params]
genesis_epoch_length = 1743

# params can add the following options for configuration, keep the original genesis_epoch_length value

initial_primary_epoch_reward = 1_917_808_21917808

secondary_epoch_reward = 613_698_63013698

max_block_cycles = 10_000_000_000

cellbase_maturity = 0

primary_epoch_reward_halving_interval = 8760

epoch_duration_target = 14400

# For development and testing purposes only.
# Keep difficulty be permanent if the pow is Dummy. (default: false)
permanent_difficulty_in_dummy = true

[params.hardfork]
# Modify ckb2023 start time
ckb2023 = 0

# Change pow.func to Dummy
[pow]
func = "Dummy"