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/thrackle-io/fre-quickstart and clicking the “Use this template” button on GitHub.

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.

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 within 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

After running this command, it will inject the beforeXXX() modifier within the function specified within the policy.json file. Verify the contract compiles and deploy the contract with the following commands:

forge script script/ExampleContract.s.sol --ffi --broadcast -vvv --non-interactive --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”