The Espresso Sequencer offers rollups credible neutrality and enhanced interoperability, without compromising on scale. Consisting of a data availability solution and a decentralized network of nodes that sequences transactions, layer-2 rollups can leverage the Espresso Sequencer to give developers and end users fast confirmations, low (and fair) fees, and robust infrastructure.
The diagram below shows how the Espresso Confirmation Layer fits into the rollup centric Ethereum ecosystem. See Architecture for details.
In order for ZK rollups to rely on blocks produced by Espresso as a source of transactions, it is required to adjust the circuit that encodes the state update logic. See zk-rollups integration for more details.
Refer to sequencer-example-l2 for instructions on how to run a dockerized Espresso Sequencer network with an example Layer 2 rollup application.
- Obtain code:
git clone [email protected]:EspressoSystems/espresso-sequencer. - Make sure nix is installed.
- Activate the environment with
nix-shell, ornix develop, ordirenv allowif using direnv. - For installation without nix please see ubuntu.md.
The rust code documentation can be found at sequencer.docs.espressosys.com. Please note the disclaimer about API stability at the end of the readme.
To generate the documentation locally and view it in the browser, run
just doc --open
just pull # to pull docker images
just test
make doc
Docker images and the docker-compose-demo.yaml file are provided for convenience. The
Docker-based demo fetches the images from the ghcr repository, where they are updated with every push to main on
GitHub. For testing uncommitted changes, you can also run the binaries by manually building and running the services.
Build all executables with cargo build --release. You may then start a sequencer network. First, start an
orchestrator. Choose a port $PORT to run it on and decide how many sequencer nodes $N you will use, then run
target/release/orchestrator -p $PORT -n $N.
The sequencer will distribute a HotShot configuration to all the nodes which connect to it, which specifies consensus
parameters like view timers. There is a default config, but you can override any parameters you want by passing
additional options to the orchestrator executable. Run target/release/orchestrator --help to see a list of available
options.
Next, you must launch a cdn instance, which is necessary to facilitate consensus.
just dev-cdn -- -p 1738In this case, we run it on port 1738.
Once you have started the orchestrator and the CDN, you must connect $N sequencer nodes to them, after which the
network will start up automatically. To start one node, run
target/release/sequencer \
--orchestrator-url http://localhost:$PORT \
--cdn-endpoint "127.0.0.1:1738" \
-- http --port 8083 -- query --storage-path storage -- submitA useful Bash snippet for running $N nodes simultaneously in the background of your shell is:
for i in `seq $N`; do
target/release/sequencer \
--orchestrator-url http://localhost:$PORT \
--cdn-endpoint "127.0.0.1:1738" \
doneFor running a full demo natively run just demo-native.
A foundry project for the contracts specific to HotShot can be found in the directory contracts.
To compile
forge buildTo run the tests
just sol-testIn order to avoid constant warnings about checksum mismatches with svm-rs
managed solc we set FOUNDRY_SRC to solc installed via flake.nix.
- To use the contracts from rust generate the rust contracts bindings:
just gen-bindings. - Bindings are only generated for contracts in the
contracts/srcfolder
To generate documentation in ./docs for solidity code run
forge docTo deploy the contracts to a local testnet, first run a dev chain (e.g. anvil), then run
forge script DeployHotShot --broadcast --rpc-url local
To deploy to sepolia set SEPOLIA_RPC_URL and MNEMONIC env vars and run
forge script DeployHotShot --broadcast --rpc-url sepolia
To additionally verify the contact on etherscan set the ETHERSCAN_API_KEY env var and run
forge script DeployHotShot --broadcast --rpc-url sepolia --verify
Running the script will save a file with details about the deployment in contracts/broadcast/$CHAIN_ID.
- code for demo purposes goes into the
contracts/demofolder - code that eventually ends up in production goes into the
contracts/srcfolder
The gas consumption for verifying a plonk proof as well as updating the state of the light client contract can be seen by running:
> just gas-benchmarks
> cat gas-benchmarks.txt
[PASS] test_verify_succeeds() (gas: 507774)
[PASS] testCorrectUpdateBench() (gas: 594533)
In order to profile the gas consumption of the light client contract do the following:
- Set the environment variables
SEPOLIA_RPC_URL,MNEMONICandETHERSCAN_API_KEY. just lc-contract-profiling-sepolia- Create an account on sentio.xyz.
- Use the hash of the transaction generated in step two when calling the function
newFinalizedStatein order to obtain the gas profile.
This is only necessary to fetch private images.
- Go to your github profile
- Developer Settings > Personal access tokens > Personal access tokens (classic)
- Generate a new token
- for the scope options of the token, tick the repo box.
- Run
docker login ghcr.io --username <you_github_id> --password <your_personal_access_token>
(c) 2022 Espresso Systems espresso-sequencer was developed by Espresso Systems. While we plan to adopt an open
source license, we have not yet selected one. As such, all rights are reserved for the time being. Please reach out to
us if you have thoughts on licensing.
DISCLAIMER: This software is provided "as is" and its security has not been externally audited. Use at your own risk.
DISCLAIMER: The Rust library crates provided in this repository are intended primarily for use by the binary targets in this repository. We make no guarantees of public API stability. If you are building on these crates, reach out by opening an issue to discuss the APIs you need.