This QuickStart will guide you through using the Forte Rules Engine in a local anvil development environment utilizing the Forte Rules Engine SDK. Following this guide, you will walk through the entire Forte Rules Engine workflow:
  1. Set up your environment
  2. Create a policy
  3. Integrate and deploy an example contract
  4. Apply the policy to the example contract
  5. Verify functionality
NOTE: This guide was developed in a MacOS environment, some modification may be necessary to suit a Linux/Windows environment.

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1. Set up your environment

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Environment dependencies

This guide assumes the following tools are installed and configured correctly. Please see each tool’s installation instructions for more details:

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Build

Create a copy of our template repository in your own github account by navigating here: https://github.com/forte-service-company-ltd/fre-quickstart and clicking the “Use this template” button on GitHub.
Create new repository from template
Next, clone the freshly created repository to your local machine: 
git clone https://github.com/<YOUR_GITHUB_USERNAME>/fre-quickstart
If you named the repository something different than fre-quickstart, use that name in the clone command instead.
Navigate to the repository in your local shell. To build the repository, run the following commands: 
npm install
forge install

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Start a local Anvil chain

An Anvil dumpState file is provided with a pre-deployed Rules Engine instance. Start the local Anvil instance in a terminal window with the following command: 
anvil --load-state anvilState.json
Listening on 127.0.0.1:8545 should be the last thing displayed if the state file was successfuly loaded. Leave this Anvil instance running in this terminal for the rest of the quickstart. It may be restarted at any time but restarting will lose any on-chain progress you’ve made during the quickstart.

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Configure your local environment

The .env.sample environment file contains the values needed to continue this guide. Expand the Accordion below for more information.
RPC_URL - The RPC endpoint to utilize when interacting with an EVM chain. This is defaulted to a local anvil RPC that is enabled when starting anvil. This can be updated to point to any testnet/mainnet RPC if desired. See anvil for more details.
# local anvil RPC, change this if you're deploying to a network
RPC_URL=http://127.0.0.1:8545
PRIV_KEY - The private key for the account that will be performing the actions outlined in this guide. This is defaulted to a widely known default Anvil account for the purposes of this guide. It is recommended that this be updated prior to deploying to any testnet or mainnet.
# local anvil account private key, change to your deployer wallet key when using a live network
PRIV_KEY=0xac0974bec39a17e36ba4a6b4d238ff944bacb478cbed5efcae784d7bf4f2ff80
RULES_ENGINE_ADDRESS - The address of the deployed Rules Engine instance on the target RPC’s chain. This is defaulted to the address where the Rules Engine was deployed in the anvilState.json file. For additional chain locations, please see the Forte Rules Engine docs.
# address of the rules engine within the anvil state file
RULES_ENGINE_ADDRESS=0x8A791620dd6260079BF849Dc5567aDC3F2FdC318
Copy the sample environment file and then source the file to make those values available in your terminal. 
cp .env.sample .env

source .env
The SDK utilizes the Rules Engine address and private key values from the environment file. This requires that you name your file .env, which enables the SDK to access the values.

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2. Create a sample policy

To use the Rules engine, we must first create a policy. A default policy has been written for you within the policy.json that is tailored to work with the ExampleContract. To create this policy in the Rules Engine, run the following command: 
npx tsx index.ts setupPolicy policy.json
Note the returned Policy Id, for this example the Policy Id should be 1, and create a local environment variable to store this Id for uses in subsequent commands: 
export POLICY_ID=1
This policy now exists, but no contracts are yet subscribed to it.

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3. Integrate and deploy an example contract

The ExampleContract is a blank contract that conforms to a standard ERC20 interface transfer() function. The file does not store any data. The integration of the Rules Engine occurs by adding a modifier. This modifier may be generated by passing the policy information, destination modifier filename, and the example contract to the SDK. The SDK will process the policy, generate modifiers within the specified modifier file for each function within the Policy, and inject these newly generated modifiers into the supplied contract. This has been scripted in the index.ts with the following command: 
npx tsx index.ts injectModifiers policy.json src/RulesEngineIntegration.sol src/ExampleContract.sol
Important! You must adjust the created src/RulesEngineIntegration.sol file to be able to deploy your example contract and continue the Quickstart. Read this next section!
After running this command, the src/RulesEngineIntegration.sol file will be created for you. The /src/ExampleContract.sol will be edited to import this new contract, extend it, and add the before<functionName>() modifier to the function specified within the policy.json file. The src/RulesEngineIntegration.sol will contain a function named setCallingContractAdmin that requires some adjustments – this is intentional. For the purpose of the quickstart you can either remove this function completely or update it to ensure only the deployer can call the function. You will not be able to compile or deploy the ExampleContract.sol until you do this.
As mentioned above, you can simply remove the function or add the override keyword and ensure it calls the parent function. Alternatively, see the other tab below for one way to ensure only the deployer can call this function.
function setCallingContractAdmin(address callingContractAdmin) public override {
    super.setCallingContractAdmin(callingContractAdmin);
}
After updating the setCallingContractAdmin implementation you’re ready to deploy the example contract: 
forge script script/ExampleContract.s.sol --broadcast --rpc-url $RPC_URL --private-key $PRIV_KEY
Note the contract address, and export the address in your local terminal for subsequent testing. 
export CONTRACT_ADDRESS=<0xYourContractAddress>

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4. Apply the policy to the example contract

The ExampleContract extends the RulesEngineClient to encapsulate storing the Rules Engine address and checks. It is recommended that all calling contracts extend this contract. This ensures calling contracts will only invoke the Rules Engine checks if the Rules Engine Address is specified. Set the Rules Engine Address in the ExampleContract via the following command: First, we need to set the Rules Engine Address for the ExampleContract. 
cast send $CONTRACT_ADDRESS "setRulesEngineAddress(address)" $RULES_ENGINE_ADDRESS --rpc-url $RPC_URL --private-key $PRIV_KEY
To verify the address was set correct, the following commmand should return the same Rules Engine Address: 
cast call $CONTRACT_ADDRESS "rulesEngineAddress()(address)" --rpc-url $RPC_URL
Next, you need to set the Calling Contract Admin: 
cast send $CONTRACT_ADDRESS "setCallingContractAdmin(address)" $USER_ADDRESS --rpc-url $RPC_URL --private-key $PRIV_KEY
The last thing to do is to subscribe our example contract to the Policy we created. 
npx tsx index.ts applyPolicy $POLICY_ID $CONTRACT_ADDRESS

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5. Verify Functionality

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Test Success Condition

cast send $CONTRACT_ADDRESS "transfer(address,uint256)" 0x70997970C51812dc3A010C7d01b50e0d17dc79C8 10001 --rpc-url $RPC_URL --private-key $PRIV_KEY
You should receive a successful transaction!

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Test Failure Condition

cast send $CONTRACT_ADDRESS "transfer(address,uint256)" 0x70997970C51812dc3A010C7d01b50e0d17dc79C8 9999 --rpc-url $RPC_URL --private-key $PRIV_KEY
You should receive a revert with the text “Failed Test”