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https://github.com/smartcontractkit/chainlink-mix

Working with smart contracts with eth-brownie, python, and Chainlink.
https://github.com/smartcontractkit/chainlink-mix

brownie chainlink eth-brownie ethereum infura python smart-contracts

Last synced: about 1 month ago
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Working with smart contracts with eth-brownie, python, and Chainlink.

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README 

        
> ⚠️⚠️⚠️

> This repo uses the eth-brownie development toolkit which is [no longer maintained by its creators](https://github.com/eth-brownie/brownie?tab=readme-ov-file#brownie).

> Therefore this repo is not maintained actively either.

> we recommend you check out the [Chainlink starter kits](https://github.com/smartcontractkit/starter-kits) to find other repos that you can use to

> get started quickly. We recommend the use of the Hardhat or Foundry starter kits for most use cases.



# chainlink-mix



> NOTE: The new default is Sepolia.

> NOTE: This has been recently updated for better compatibility with local blockchains. Check out the scripts to learn more.










Chainlink Brownie logo









[![Average time to resolve an issue](http://isitmaintained.com/badge/resolution/smartcontractkit/chainlink-mix.svg)](http://isitmaintained.com/project/smartcontractkit/chainlink-mix "Average time to resolve an issue")

[![Percentage of issues still open](http://isitmaintained.com/badge/open/smartcontractkit/chainlink-mix.svg)](http://isitmaintained.com/project/smartcontractkit/chainlink-mix "Percentage of issues still open")



This is a repo to work with and use Chainlink smart contracts in a python environment. If you're brand new to Chainlink, check out the beginner walk-through in remix to [learn the basics.](https://docs.chain.link/docs/beginners-tutorial)



You can also check out the more advanced Chainlink tutorials there as well.



- [chainlink-mix](#chainlink-mix)

  - [Prerequisites](#prerequisites)

  - [Installation](#installation)

  - [Testnet Development](#testnet-development)

  - [Local Development](#local-development)

  - [Running Scripts and Deployment](#running-scripts-and-deployment)

    - [Chainlink Price Feeds](#chainlink-price-feeds)

    - [Chainlink VRF](#chainlink-vrf)

    - [Chainlink API Call](#chainlink-api-call)

    - [Chainlink Automation Deployment](#chainlink-automation-deployment)

    - [Local Development](#local-development-1)

  - [Testing](#testing)

    - [To test development / local](#to-test-development--local)

    - [To test mainnet-fork](#to-test-mainnet-fork)

    - [To test a testnet](#to-test-a-testnet)

  - [Adding additional Chains](#adding-additional-chains)

  - [Linting](#linting)

  - [Resources](#resources)

  - [License](#license)



## Prerequisites



Please install or have installed the following:



- [nodejs and npm](https://nodejs.org/en/download/)

- [python](https://www.python.org/downloads/)



## Installation



1. [Install Brownie](https://eth-brownie.readthedocs.io/en/stable/install.html), if you haven't already. Here is a simple way to install brownie.



```bash

python3 -m pip install --user pipx

python3 -m pipx ensurepath

# restart your terminal

pipx install eth-brownie

```



Or, if that doesn't work, via pip



```bash

pip install eth-brownie

```



2. Download the mix and install dependencies.



```bash

brownie bake chainlink-mix

cd chainlink-mix

pip install -r requirements.txt

```



This will open up a new Chainlink project. Or, you can clone from source:



```bash

git clone https://github.com/PatrickAlphaC/chainlink-mix

cd chainlink-mix

```



## Testnet Development



If you want to be able to deploy to testnets, do the following.



Set your `WEB3_INFURA_PROJECT_ID`, and `PRIVATE_KEY` [environment variables](https://www.twilio.com/blog/2017/01/how-to-set-environment-variables.html).



You can get a `WEB3_INFURA_PROJECT_ID` by getting a free trial of [Infura](https://infura.io/). At the moment, it does need to be infura with brownie. If you get lost, you can [follow this guide](https://ethereumico.io/knowledge-base/infura-api-key-guide/) to getting a project key. You can find your `PRIVATE_KEY` from your ethereum wallet like [metamask](https://metamask.io/).



You'll also need testnet ETH and LINK. You can get LINK and ETH into your wallet by using the [faucets located here](https://faucets.chain.link/). If you're new to this, [watch this video.](https://www.youtube.com/watch?v=P7FX_1PePX0). Look at the `sepolia` section for those specific testnet faucets.



You can add your environment variables to a `.env` file. You can use the [.env.example](https://github.com/smartcontractkit/chainlink-mix/blob/master/.env.example) as a template, just fill in the values and rename it to '.env'. Then, uncomment the line `# dotenv: .env` in `brownie-config.yaml`



Here is what your `.env` should look like:



```

export WEB3_INFURA_PROJECT_ID=

export PRIVATE_KEY=

```



AND THEN RUN `source .env` TO ACTIVATE THE ENV VARIABLES

(You'll need to do this every time you open a new terminal, or [learn how to set them easier](https://www.twilio.com/blog/2017/01/how-to-set-environment-variables.html))



![WARNING](https://via.placeholder.com/15/f03c15/000000?text=+) **WARNING** ![WARNING](https://via.placeholder.com/15/f03c15/000000?text=+)



DO NOT SEND YOUR PRIVATE KEY WITH FUNDS IN IT ONTO GITHUB



Otherwise, you can build, test, and deploy on your local environment.



## Local Development



For local testing [install ganache-cli](https://www.npmjs.com/package/ganache-cli)



```bash

npm install -g ganache-cli

```



or



```bash

yarn add global ganache-cli

```



All the scripts are designed to work locally or on a testnet. You can add a ganache-cli or ganache UI chain like so:



```

brownie networks add Ethereum ganache host=http://localhost:8545 chainid=1337

```



And update the brownie config accordingly. There is a `deploy_mocks` script that will launch and deploy mock Oracles, VRFCoordinators, Link Tokens, and Price Feeds on a Local Blockchain.



## Running Scripts and Deployment



This mix provides a simple template for working with Chainlink Smart Contracts. The easiest way to start is to fork the mainnet chain to a local ganache chain. This will allow you to deploy local smart contracts to interact with the [Chainlink Price Feeds](https://docs.chain.link/docs/get-the-latest-price).



> NOTE: It's highly encouraged that you work with a local chain before testing on a testnet. You'll be a much faster developer!



If Sepolia network is not added to brownie by default, run:



```

brownie networks add Ethereum sepolia host=https://sepolia.infura.io/v3/$WEB3_INFURA_PROJECT_ID chainid=11155111 explorer=https://sepolia.etherscan.io/

```



### Chainlink Price Feeds



This will deploy a smart contract to Sepolia and then read you the latest price via [Chainlink Price Feeds](https://docs.chain.link/docs/get-the-latest-price).



```

brownie run scripts/price_feed_scripts/01_deploy_price_consumer_v3.py --network sepolia

brownie run scripts/price_feed_scripts/02_read_price_feed.py --network sepolia

```



Or, you can use [ENS](https://docs.chain.link/docs/ens)



```

brownie run scripts/price_feed_scripts/02_read_price_feed_with_ens.py --network sepolia

```



Otherwise, you can fork mainnet and use that in a local ganache development environment.



```bash

brownie console --network mainnet-fork

>>> price_feeds = PriceFeedConsumer.deploy('0x5f4eC3Df9cbd43714FE2740f5E3616155c5b8419', {'from': accounts[0]})

.

.

>>> latest_price = price_feeds.getLatestPrice()

>>> latest_price

59169208540

```



You can also use [ENS](https://docs.chain.link/docs/ens) to get prices. See the [ens price feed script](./scripts/price_feed_scripts/read_price_with_ens.py) for more information.



### Chainlink VRF



This will deploy a smart contract to Sepolia and get a Random number via [Chainlink VRF](https://docs.chain.link/docs/get-a-random-number).



If you haven't created and funded a subscription on [vrf.chain.link](https://vrf.chain.link/) you can do so on the UI, or by running:



```

brownie run scripts/vrf_scripts/create_subscription.py --network sepolia

```



Before running the next scripts. Running `01_deploy_vrf` will also add your consumer contract to the registry.



```

brownie run scripts/vrf_scripts/01_deploy_vrf_consumer.py --network sepolia

brownie run scripts/vrf_scripts/02_request_randomness.py --network sepolia

brownie run scripts/vrf_scripts/03_read_random_number.py --network sepolia

```



### Chainlink API Call



This will deploy a smart contract to Sepolia and then make an API call via [Chainlink API Call](https://docs.chain.link/docs/make-a-http-get-request).



```

brownie run scripts/chainlink_api_scripts/01_deploy_api_consumer.py --network sepolia

brownie run scripts/chainlink_api_scripts/02_request_api.py --network sepolia

brownie run scripts/chainlink_api_scripts/03_read_data.py --network sepolia

```



### Chainlink Automation Deployment



This is just to show you how to deploy the Automation Compatible contracts, you can learn more about registering & using them in the [Automate Contracts](https://docs.chain.link/chainlink-automation/compatible-contracts/) section of the Chainlink documentation.



```

brownie run scripts/automation_scripts/01_deploy_automation_counter.py --network sepolia

brownie run scripts/automation_scripts/02_check_upkeep.py --network sepolia

```



### Local Development



For local development, you might want to deploy mocks. You can run the script to deploy mocks. Depending on your setup, it might make sense to _not_ deploy mocks if you're looking to fork a mainnet. It all depends on what you're looking to do though. Right now, the scripts automatically deploy a mock so they can run.



## Testing



```

brownie test

```



For more information on effective testing with Chainlink, check out [Testing Smart Contracts](https://blog.chain.link/testing-chainlink-smart-contracts/)



Tests are really robust here! They work for local development and testnets. There are a few key differences between the testnets and the local networks. We utilize mocks so we can work with fake oracles on our testnets.



There is a `test_unnecessary` folder, which is a good exercise for learning some of the nitty-gritty of smart contract development. It's overkill, so pytest will skip them intentionally. It also has a `test_samples` folder, which shows an example Chainlink API call transaction receipt.



### To test development / local



```bash

brownie test

```



### To test mainnet-fork



This will test the same way as local testing, but you will need a connection to a mainnet blockchain (like with the infura environment variable.)



```bash

brownie test --network mainnet-fork

```



### To test a testnet



Sepolia is currently supported. Please check the Chainlink docs for which products are supported on which chains.



```bash

brownie test --network sepolia

```



## Adding additional Chains



If the blockchain is EVM Compatible, adding new chains can be accomplished by something like:



```

brownie networks add Ethereum binance-smart-chain host=https://bsc-dataseed1.binance.org chainid=56

```



or, for a fork:



```

brownie networks add development binance-fork cmd=ganache-cli host=http://127.0.0.1 fork=https://bsc-dataseed1.binance.org accounts=10 mnemonic=brownie port=8545

```



## Linting



```

pip install black

pip install autoflake

autoflake --in-place --remove-unused-variables --remove-all-unused-imports -r .

black .

```



If you're using [vscode](https://code.visualstudio.com/) and the [solidity extension](https://github.com/juanfranblanco/vscode-solidity), you can create a folder called `.vscode` at the root folder of this project, and create a file called `settings.json`, and add the following content:



```json

{

  "solidity.remappings": [

    "@chainlink/=[YOUR_HOME_DIR]/.brownie/packages/smartcontractkit/[email protected]",

    "@openzeppelin/=[YOUR_HOME_DIR]/.brownie/packages/OpenZeppelin/[email protected]"

  ]

}

```



This will quiet the linting errors it gives you.



## Resources



To get started with Brownie:



- [Chainlink Documentation](https://docs.chain.link/docs)

- Check out the [Chainlink documentation](https://docs.chain.link/docs) to get started from any level of smart contract engineering.

- Check out the other [Brownie mixes](https://github.com/brownie-mix/) that can be used as a starting point for your own contracts. They also provide example code to help you get started.

- ["Getting Started with Brownie"](https://medium.com/@iamdefinitelyahuman/getting-started-with-brownie-part-1-9b2181f4cb99) is a good tutorial to help you familiarize yourself with Brownie.

- For more in-depth information, read the [Brownie documentation](https://eth-brownie.readthedocs.io/en/stable/).



Any questions? Join our [Discord](https://discord.gg/2YHSAey)



## License



This project is licensed under the [MIT license](LICENSE).