Development guide

This document covers development-related actions in ZKsync.

Initializing the project

To setup the main toolkit, zk, simply run:

zk

You may also configure autocompletion for your shell via:

zk completion install

Once all the dependencies were installed, project can be initialized:

zk init

This command will do the following:

Generate $ZKSYNC_HOME/etc/env/target/dev.env file with settings for the applications.
Initialize docker containers with reth Ethereum node for local development.
Download and unpack files for cryptographical backend.
Generate required smart contracts.
Compile all the smart contracts.
Deploy smart contracts to the local Ethereum network.
Create “genesis block” for server.

Initializing may take pretty long, but many steps (such as downloading & unpacking keys and initializing containers) are required to be done only once.

Usually, it is a good idea to do zk init once after each merge to the main branch (as application setup may change).

Additionally, there is a subcommand zk clean to remove previously generated data. Examples:

zk clean --all # Remove generated configs, database and backups.
zk clean --config # Remove configs only.
zk clean --database # Remove database.
zk clean --backups # Remove backups.
zk clean --database --backups # Remove database *and* backups, but not configs.

When do you need it?

If you have an initialized database and want to run zk init, you have to remove the database first.
If after getting new functionality from the main branch your code stopped working and zk init doesn’t help, you may try removing $ZKSYNC_HOME/etc/env/target/dev.env and running zk init once again. This may help if the application configuration has changed.

If you don’t need all of the zk init functionality, but just need to start/stop containers, use the following commands:

zk up   # Set up `reth` and `postgres` containers
zk down # Shut down `reth` and `postgres` containers

When actively changing something that affects infrastructure (for example, contracts code), you normally don’t need the whole init functionality, as it contains many external steps (e.g. deploying ERC20 tokens) which don’t have to be redone.

For this case, there is an additional command:

zk reinit

This command does the minimal subset of zk init actions required to “reinitialize” the network. It assumes that zk init was called in the current environment before. If zk reinit doesn’t work for you, you may want to run zk init instead.

Committing changes

zksync uses pre-commit and pre-push git hooks for basic code integrity checks. Hooks are set up automatically within the workspace initialization process. These hooks will not allow to commit the code which does not pass several checks.

Currently the following criteria are checked:

Rust code should always be formatted via cargo fmt.
Other code should always be formatted via zk fmt.
Dummy Prover should not be staged for commit (see below for the explanation).

Using Dummy Prover

By default, the chosen prover is a “dummy” one, meaning that it doesn’t actually compute proofs but rather uses mocks to avoid expensive computations in the development environment.

To switch dummy prover to real prover, one must change dummy_verifier to false in contracts.toml for your env (most likely, etc/env/base/contracts.toml) and run zk init to redeploy smart contracts.

Testing

Running the rust unit-tests:
```
zk test rust
```

Running a specific rust unit-test:

zk test rust --package <package_name> --lib <mod>::tests::<test_fn_name>
# e.g. zk test rust --package zksync_core --lib eth_sender::tests::resend_each_block

Running the integration test:

zk server           # Has to be run in the 1st terminal
zk test i server    # Has to be run in the 2nd terminal

Running the benchmarks:
```
zk f cargo bench
```

Running the loadtest:

zk server # Has to be run in the 1st terminal
zk prover # Has to be run in the 2nd terminal if you want to use real prover, otherwise it's not required.
zk run loadtest # Has to be run in the 3rd terminal

Contracts

Re-build contracts

zk contract build

Publish source code on etherscan

zk contract publish

ZKsync Era Documentation