starknet-devnet 0.2.8

A local testnet for Starknet

Introduction

A Flask wrapper of Starknet state. Similar in purpose to Ganache.

Aims to mimic Starknet's Alpha testnet, but with simplified functionality.

Contents

• Install
• Disclaimer
• Run
• Interaction
• JSON-RPC API
• Dumping and Loading
• Hardhat Integration
• L1-L2 Postman Communication
• Block Explorer
• Lite Mode
• Restart
• Advancing time
• Contract debugging
• Predeployed accounts
• Mint token - Local faucet
• Devnet speed-up troubleshooting
• Development

Install

pip install starknet-devnet

Requirements

Works with Python versions >=3.7.2 and <3.10.

On Ubuntu/Debian, first run:

sudo apt install -y libgmp3-dev

On Mac, you can use brew:

brew install gmp

Disclaimer

• Devnet should not be used as a replacement for Alpha testnet. After testing on Devnet, be sure to test on testnet (alpha-goerli)!
• Specifying a block by its hash/number is not supported for contract calls. All interaction is done with the latest block.
• There is no pending block. A new block is generated with each transaction.
• Sending transactions with max_fee set to 0 is supported (not supported on alpha-mainnet or alpha-goerli).

Run

Installing the package adds the starknet-devnet command.

usage: starknet-devnet [-h] [-v] [--host HOST] [--port PORT]

Run a local instance of Starknet Devnet

optional arguments:
  -h, --help            show this help message and exit
  -v, --version         Print the version
  --host HOST           Specify the address to listen at; defaults to
                        127.0.0.1 (use the address the program outputs on
                        start)
  --port PORT, -p PORT  Specify the port to listen at; defaults to 5050
  --load-path LOAD_PATH
                        Specify the path from which the state is loaded on
                        startup
  --dump-path DUMP_PATH
                        Specify the path to dump to
  --dump-on DUMP_ON     Specify when to dump; can dump on: exit, transaction
  --lite-mode           Applies all lite-mode-* optimizations by disabling some features.
  --lite-mode-block-hash
                        Disables block hash calculation
  --lite-mode-deploy-hash
                        Disables deploy tx hash calculation
  --accounts ACCOUNTS   Specify the number of accounts to be predeployed;
                        defaults to 10
  --initial-balance INITIAL_BALANCE, -e INITIAL_BALANCE
                        Specify the initial balance of accounts to be
                        predeployed; defaults to 1e+21 (wei)
  --seed SEED           Specify the seed for randomness of accounts to be
                        predeployed
  --start-time START_TIME
                        Specify the start time of the genesis block in Unix
                        time seconds
  --gas-price GAS_PRICE, -g GAS_PRICE
                        Specify the gas price in wei per gas unit; defaults to
                        1e+11

You can run starknet-devnet in a separate shell, or you can run it in background with starknet-devnet &. Check that it's alive by running the following (address and port my vary if you specified a different one with --host or --port):

curl http://127.0.0.1:5050/is_alive

Run with Docker

Devnet is available as a Docker image (shardlabs/starknet-devnet):

docker pull shardlabs/starknet-devnet:<TAG>

Versions and Tags

Image tags correspond to Devnet versions as on PyPI and GitHub, with the latest tag used for the latest image. These images are built for linux/amd64. To use the arm64 versions, since 0.1.23 you can append -arm to the tag. E.g.:

• shardlabs/starknet-devnet:0.2.8 - image for the amd64 architecture
• shardlabs/starknet-devnet:0.2.8-arm - image for the arm64 architecture
• shardlabs/starknet-devnet:latest-arm

By appending the -seed0 suffix, you can access images which predeploy funded accounts with --seed 0, thus always deploying the same set of accounts. E.g.:

• shardlabs/starknet-devnet:0.2.8-seed0
• shardlabs/starknet-devnet:latest-seed0
• shardlabs/starknet-devnet:0.2.8-arm-seed0

The server inside the container listens to the port 5050, which you need to publish to a desired <PORT> on your host machine:

docker run -p [HOST:]<PORT>:5050 shardlabs/starknet-devnet

E.g. if you want to use your host machine's 127.0.0.1:5050, you need to run:

docker run -p 127.0.0.1:5050:5050 shardlabs/starknet-devnet

You may ignore any address-related output logged on container startup (e.g. Running on all addresses or Running on http://172.17.0.2:5050). What you will use is what you specified with the -p argument.

If you don't specify the HOST part, the server will indeed be available on all of your host machine's addresses (localhost, local network IP, etc.), which may present a security issue if you don't want anyone from the local network to access your Devnet instance.

Interaction

• Interact with Devnet as you would with the official Starknet Alpha testnet.
• The exact underlying API is not exposed for the same reason Alpha testnet does not expose it.
• To use Devnet with Starknet CLI, provide Devnet's URL to the --gateway_url and --feeder_gateway_url options of Starknet CLI commands.
• The following Starknet CLI commands are supported:
  • call
  • declare
  • deploy
  • estimate_fee
  • get_block (currently pending block is not supported)
  • get_block_traces
  • get_class_by_hash
  • get_class_hash_at
  • get_code
  • get_full_contract
  • get_state_update
  • get_storage_at
  • get_transaction
  • get_transaction_receipt
  • get_transaction_trace
  • invoke
  • tx_status
• The following Starknet CLI commands are not supported:
  • get_contract_addresses

JSON-RPC API

Devnet also partially supports JSON-RPC API (v0.15.0: specifications) and WRITE API (v0.3.0: specifications). It can be reached under /rpc. For an example:

POST /rpc
{
  "jsonrpc": "2.0",
  "method": "starknet_protocolVersion",
  "params": [],
  "id": 0
}

Response:

{
  "id": 0,
  "jsonrpc": "2.0",
  "result": "0x302e382e30"
}

Hardhat integration

If you're using the Hardhat plugin, see here on how to edit its config file to integrate Devnet.

Postman integration

Postman is a Starknet utility that allows testing L1 <> L2 interaction. To utilize this, you can use starknet-hardhat-plugin, as witnessed in this example. Or you can directly interact with the two Postman-specific endpoints:

Postman - Load

POST /postman/load_l1_messaging_contract
{
  "networkUrl": "http://localhost:8545",
  "address": "0x123...def"
}

Loads a StarknetMockMessaging contract. The address parameter is optional; if provided, the StarknetMockMessaging contract will be fetched from that address, otherwise a new one will be deployed.

networkUrl is the URL of the JSON-RPC API of the L1 node you've run locally or that already exists; possibilities include, and are not limited to:

• Goerli testnet
• Ganache
• Geth
• Hardhat node.

Postman - Flush

POST /postman/flush

Goes through the newly enqueued messages, sending them from L1 to L2 and from L2 to L1. Requires no body.

Postman - disclaimer

This method of L1 <> L2 communication testing differs from Starknet Alpha networks. Taking the L1L2Example.sol contract in the starknet documentation:

constructor(IStarknetCore starknetCore_) public {
    starknetCore = starknetCore_;
}

The constructor takes an IStarknetCore contract as argument, however for Devnet L1 <> L2 communication testing, this will have to be replaced with the MockStarknetMessaging.sol contract:

constructor(MockStarknetMessaging mockStarknetMessaging_) public {
    starknetCore = mockStarknetMessaging_;
}

Dumping

To preserve your Devnet instance for future use, there are several options:

• Dumping on exit (handles Ctrl+C, i.e. SIGINT, doesn't handle SIGKILL):

starknet-devnet --dump-on exit --dump-path <PATH>

• Dumping after each transaction (done in background, doesn't block):

starknet-devnet --dump-on transaction --dump-path <PATH>

• Dumping on request (replace <HOST>, <PORT> and <PATH> with your own):

curl -X POST http://<HOST>:<PORT>/dump -d '{ "path": <PATH> }' -H "Content-Type: application/json"

Loading

To load a preserved Devnet instance, the options are:

• Loading on startup:

starknet-devnet --load-path <PATH>

• Loading on request:

curl -X POST http://<HOST>:<PORT>/load -d '{ "path": <PATH> }' -H "Content-Type: application/json"

Enabling dumping and loading with Docker

To enable dumping and loading if running Devnet in a Docker container, you must bind the container path with the path on your host machine.

This example:

• Relies on Docker bind mount; try Docker volume instead.
• Assumes that /actual/dumpdir exists. If unsure, use absolute paths.
• Assumes you are listening on 127.0.0.1:5050.

If there is dump.pkl inside /actual/dumpdir, you can load it with:

docker run \
  -p 127.0.0.1:5050:5050 \
  --mount type=bind,source=/actual/dumpdir,target=/dumpdir \
  shardlabs/starknet-devnet \
  --load-path /dumpdir/dump.pkl

To dump to /actual/dumpdir/dump.pkl on Devnet shutdown, run:

docker run \
  -p 127.0.0.1:5050:5050 \
  --mount type=bind,source=/actual/dumpdir,target=/dumpdir \
  shardlabs/starknet-devnet \
  --dump-on exit --dump-path /dumpdir/dump.pkl

Block explorer

A local block explorer (Voyager), as noted here, apparently cannot be set up to work with Devnet. Read more in this issue.

Block

Devnet start with a genesis block.

GENESIS_BLOCK_NUMBER = 0

GENESIS_BLOCK_HASH = "0x0"

You can create empty block without transaction.

POST /create_block

Response:

{
    "transactions": [],
    "parent_block_hash": "0x0",
    "timestamp": 1659457385,
    "state_root": "004bee3ee...",
    "gas_price": "0x174876e800",
    "sequencer_address": "0x4bbfb0d1aa...",
    "transaction_receipts": [],
    "starknet_version": "0.9.1",
    "block_hash": "0x1",
    "block_number": 1,
    "status": "ACCEPTED_ON_L2"
}

Lite mode

To improve Devnet performance, instead of calculating the actual hash of deployment transactions and blocks, sequential numbering can be used (0x0, 0x1, 0x2, ...).

Consider passing these CLI flags on Devnet startup:

• --lite-mode enables all of the optimizations described below (same as using all of the flags below)
• --lite-mode-deploy-hash
  • disables the calculation of transaction hash for deploy transactions
• --lite-mode-block-hash
  • disables the calculation of block hash
  • disables get_state_update functionality

Restart

Devnet can be restarted by making a POST /restart request. All of the deployed contracts, blocks and storage updates will be restarted to the empty state. If you're using the Hardhat plugin, run await starknet.devnet.restart().

Advancing time

Block timestamp can be manipulated by seting the exact time or seting the time offset. Timestamps methods won't generate a new block, but they will modify the time of the following blocks. All values should be set in Unix time and seconds.

Set time

Sets the exact time of the next generated block. All subsequent blocks will keep the set offset.

POST /set_time
{
    "time": TIME_IN_SECONDS
}

Warning: block time can be set in the past and lead to unexpected behaviour!

Increase time

Increases the time offset for each generated block.

POST /increase_time
{
    "time": TIME_IN_SECONDS
}

Start time arg

Devnet can be started with the --start-time argument.

starknet-devnet --start-time START_TIME_IN_SECONDS

Contract debugging

If your contract is using print in cairo hints (it was compiled with the --disable-hint-validation flag), Devnet will output those lines together with its regular server output. Read more about hints here. To filter out just your debug lines, redirect stderr to /dev/null when starting Devnet:

starknet-devnet 2> /dev/null

To enable printing with a dockerized version of Devnet set PYTHONUNBUFFERED=1:

docker run -p 127.0.0.1:5050:5050 -e PYTHONUNBUFFERED=1 shardlabs/starknet-devnet

Predeployed accounts

Devnet predeploys --accounts with some --initial-balance. The accounts get charged for transactions according to the --gas-price. A --seed can be used to regenerate the same set of accounts. Read more about it in the Run section.

To get the code of the account (currently OpenZeppelin v0.2.1), use one of the following:

• GET /get_code?contractAddress=<ACCOUNT_ADDRESS>
• Starknet CLI: starknet get_code --contract_address <ACCOUNT_ADDRESS> --feeder_gateway_url <DEVNET_URL>
• OpenZeppelin's cairo-contract repository

You can use the accounts in e.g. starknet-hardhat-plugin via:

const account = await starknet.getAccountFromAddress(
  ADDRESS,
  PRIVATE_KEY,
  "OpenZeppelin"
);

Fetch predeployed accounts

GET /predeployed_accounts

Response:

[
  {
    "initial_balance": 1e+21,
    "address": "0x7c3e2...",
    "private_key": "0x6160...",
    "public_key": "0x6a5540..."
  },
  ...
]

Fetch account balance

GET /account_balance?address=<HEX_ADDRESS>

Response:

{
  "amount": 123...456,
  "unit": "wei"
}

Mint token - Local faucet

Other than using prefunded predeployed accounts, you can also add funds to an account that you deployed yourself.

The ERC20 contract used for minting ETH tokens and charging fees is at: 0x62230ea046a9a5fbc261ac77d03c8d41e5d442db2284587570ab46455fd2488

Query fee token address

GET /fee_token

Response:

{
  "symbol":"ETH",
  "address":"0x62230ea046a9a5fbc261ac77d03c8d41e5d442db2284587570ab46455fd2488",
}

Mint with a transaction

By not setting the lite parameter or by setting it to false, new tokens will be minted in a separate transaction. You will receive the hash of this transaction, as well as the new balance after minting in the response.

amount needs to be an integer (or a float whose fractional part is 0, e.g. 1000.0 or 1e21)

POST /mint
{
    "address": "0x6e3205f...",
    "amount": 500000
}

Response:

{
    "new_balance": 500000,
    "unit": "wei",
    "tx_hash": "0xa24f23..."
}

Mint lite

By setting the lite parameter, new tokens will be minted without generating a transaction, thus executing faster.

POST /mint
{
    "address": "0x6e3205f...",
    "amount": 500000,
    "lite": true
}

Response:

{
    "new_balance": 500000,
    "unit": "wei",
    "tx_hash": null
}

Devnet speed-up troubleshooting

If you are not satisfied with Devnet's performance, consider the following:

• Make sure you are using the latest version of Devnet because new improvements are added regularly.
• Try using lite-mode.
• If minting tokens, set the lite parameter.
• Using an installed Devnet should be faster than running it with Docker.
• If you are running Devnet with Docker on an ARM machine (e.g. M1), make sure you are using the appropriate image tag
• If Devnet has been running for some time, try restarting it (either by killing it or by using the restart functionality).
• Keep in mind that:
  • The first transaction is always a bit slower due to lazy loading.
  • Tools you use for testing (e.g. the Hardhat plugin) add their own overhead.
  • Bigger contracts are more time consuming.

Development

If you're a developer willing to contribute, be sure to have installed Poetry and all the dependency packages by running the following script. You are expected to have npm.

./scripts/install_dev_tools.sh

Development - Run

poetry run starknet-devnet

Development - Run in debug mode

./scripts/starknet_devnet_debug.sh

Development - Lint

./scripts/lint.sh

Development - Test in parallel

./scripts/test.sh 
#optional you can pass <TEST_DIR>/

or manually you can set -s -v for verbose and replace 'auto' with number of workers (recommended same as CPU cores)

poetry run pytest -n auto --dist loadscope test/  
# parallel testing using auto detect number of CPU cores and spawn same amount of workers

Development - Test

When running tests locally, do it from the project root:

./scripts/compile_contracts.sh # first generate the artifacts

poetry run pytest test/

poetry run pytest -s -v test/ # for more verbose output

poetry run pytest test/<TEST_FILE> # for a single file

poetry run pytest test/<TEST_FILE>::<TEST_CASE> # for a single test case

Development - Check versioning consistency

./scripts/check_versions.sh

Development - working with a local version of cairo-lang:

In pyproject.toml under [tool.poetry.dependencies] specify

cairo-lang = { path = "your-cairo-lang-package.zip" }

Development - Build

You don't need to build anything to be able to run locally, but if you need the *.whl or *.tar.gz artifacts, run

poetry build