Deploying your first Cairo 1 contract to Starknet

With version 0.11 rolling out on Starknet, you can now deploy your first Cairo 1 contracts on Starknet! Fantastic!

... But how ser?

Here is a very rough guide, before we get our doc in order

The flow

You will need to:

• Clone the Cairo repository (the tool to compile your Cairo 1 contract) at a specific height
• Install the latest version of Cairo-lang (the tool to interact with Starknet)
• Compile your contract from Cairo to Sierra, using cairo
• Declare your Sierra contract, using cairo-lang
• Deploy your contract, using cairo-lang
• Brag to your friends, using Twitter

Clone this repo

git clone https://github.com/starknet-edu/deploy-cairo1-demo
cd deploy-cairo1-demo

Installing the Cairo one compiler

If you're installing Cairo for the first time:

git clone https://github.com/starkware-libs/cairo/
cd cairo
git checkout 9c190561ce1e8323665857f1a77082925c817b4c
cargo build --all --release

If you already have Cairo installed:

cd cairo
git fetch && git pull
git checkout 9c190561ce1e8323665857f1a77082925c817b4c
cargo build --all --release

At this point you have Cairo installed in this repository.

Installing Cairo-lang

Go back to the root folder of the repo

cd ..

Set up a python virtual environment

python3.9 -m venv ~/cairo_venv_v11
source ~/cairo_venv_v11/bin/activate

If you had cairo-lang installed previously, uninstall it

pip3 uninstall cairo-lang

Install Cairo lang

pip3 install ecdsa fastecdsa sympy
pip3 install cairo-lang

Check that you have it installed correctly

starknet --version

Compile your contract using Cairo

You can use this smol demo contract to complete this test. It's a very basic event logger.

From your terminal, in the folder you installed Cairo in

cd cairo
cargo run --bin starknet-compile -- ../hello_starknet.cairo ../hello_starknet.json --replace-ids	

Congratulations, you have compiled your contracts from Cairo to Sierra!

Declare your contract using Cairo-lang

Setting environment variables

export STARKNET_NETWORK=alpha-goerli
export STARKNET_WALLET=starkware.starknet.wallets.open_zeppelin.OpenZeppelinAccount

Setting a new account for the tutorial

You need to make sure your starknet CLI is set up with a proper account contract, and funds. For safety, I'll create a new one just for this tutorial.

starknet new_account --account version_11

• You should get your expected contract address
• Send 0.1 ETH to it
• Monitor the transfer transaction. Once it has passed "pending", proceed

starknet deploy_account --account version_11

Monitor the deploy transaction. Once it has passed "pending", proceed

Declaring the contract

Go back to the root folder of the tutorial then try to declare

cd ..
starknet declare --contract hello_starknet.json --account version_11

You should receive your newly declared class hash!

Troubleshooting

Ok so here I had a problem. Using declare sent back:

Error: OSError: [Errno 8] Exec format error: '~/cairo_venv_11/lib/python3.9/site-packages/starkware/starknet/compiler/v1/bin/starknet-sierra-compile'

The reason is that cairo-lang needs to compile your sierra code, and it uses an imported rust binary 'starknet-sierra-compile' for that. But in my case, the imported binary was not built for my achitecture :-(.

So, simple: I took the 'starknet-sierra-compile' from the cairo repo, that I built locally, and replaced it in the python package. Here is a command that should work:

cp cairo/target/release/starknet-sierra-compile ~/cairo_venv_v11/lib/python3.9/site-packages/starkware/starknet/compiler/v1/bin/starknet-sierra-compile

Then try again declaring. It should work!

Deploy your contract using Cairo-lang

At this point you are back in the flow you are used to. Using the class hash you received earlier:

starknet deploy --class_hash <class_hash> --account version_11

Monitor your transaction. If it fails because of fee estimation, retry. Once your transaction is accepted_on_l2.... Congratulations! You've deployed your first Cairo 1 contract!

Bragging on Twitter

Don't forget to brag! Post your deployed contract here

And don't forget to add cool functionnalities to your contract. The Starknet edu team will release soon the Cairo 1 version of Cairo-101. In the meanwhile, you can get ideas of what to do with Cairo 1 with Starklings-cairo1

Do you want to learn more?

If you are interested in

• Learning how to develop cool stuff on Starknet
• How Starknet works
• What Cairo is
• How Stark proofs work You should join Basecamp, our free 6 weeks training program for aspiring Starknet devs. The next two cohorts start in April and you register here for a cohort in English, and aqui para una cohort en Español.