Euler Tokenlist

• Euler platform token list
• Automatic permit support detection tools
• Coingecko tokenlist with detected permit support data, updated daily

Permit detection

Detect permit support on a single token:

npm run detect-permit 0x123..def

Run detection on a token list, passing the url and a file name for the results:

npm run detect-permit:list https://tokens.coingecko.com/uniswap/all.json coingecko-tokenlist-with-permits.json

Config

The only configuration required for permit detection is a JSON RPC endpoint in a .env file.

JSON_RPC_URL=https://your-json-rpc-provider

Optionally:

• CHAIN_ID can be set, although the scripts have not been tested with chains other than Ethereum.
• MULTICALL2_ADDRESS internally the tool uses MakerDao Multicall2 contract. If CHAIN_ID is modified, this address also needs to be updated.
• DETECT_PERMIT_BATCH_SIZE controls the number of tokens processed in parallel. Default is 20, set to lower value in case of network / provider errors.

Detection logic and results

The algorithm uses a number of heuristics to automatically detect permit support in a token contract. In the first step, functions like nonces, DOMAIN_SEPARATOR, PERMIT_TYPEHASH are probed. If they return results, the token is flagged as possibly supporting permits. In the next step, the permit function is static-called with signatures constructed using common domain separator values. If the call is successful, the allowance function is called to verify the result matches the permit.

When permit support is detected, the result returned is the type of permit, with optional variant, and domain separator values.

❯ npm run detect-permit 0x6B175474E89094C44Da98b954EedeAC495271d0F

DETECTED: ALLOWED 
{
  name: 'Dai Stablecoin',
  version: '1',
  chainId: 1,
  verifyingContract: '0x6b175474e89094c44da98b954eedeac495271d0f'
}

Possible permit types are EIP2612 and ALLOWED (implementation introduced in DAI), both described in the EIP2612. Not all contracts implement the standard to the letter. For some common patterns an additional variant might be provided. Currently two EIP2612 variants are supported by the detection tool:

• UNDERSCORE_NONCES - the token implements _nonces function instead of the standard nonces
• PACKED - the permit function accepts a raw bytes signature instead of the standard r, s, v values

If detection fails but the token is flagged as possibly supporting permits, an error is returned along with a list of logs. In such cases it is necessary to review the contract manually. There might be a number of issues, like deviation from the standard or bugs. In other cases, the permit support is implemented correctly, but the domain separator is built with uncommon values. To handle these instances, the tool accepts a curated list which overrides the detection results. curated/permits.js file contains the opinionated list maintained by Euler.

When the tool is run to process the tokenlist, the result is a new tokenlist, with additional permit data in extensions property, which is compliant with the Uniswap tokenlist standard.

{
  "chainId": 1,
  "address": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48",
  "name": "USD Coin",
  "symbol": "USDC",
  "decimals": 6,
  "logoURI": "https://assets.coingecko.com/coins/images/6319/thumb/USD_Coin_icon.png?1547042389",
  "extensions": {
    "permit": {
      "type": "EIP2612",
      "domain": {
        "name": "USD Coin",
        "version": "2",
        "chainId": 1,
        "verifyingContract": "0xa0b86991c6218b36c1d19d4a2e9eb0ce3606eb48"
      }
    }
  }
}

Coingecko list with permits

The full Coingecko token list is processed daily to detect permit support in all tokens. The results are commited to the repo and available in coingecko-tokenlist-with-permits.json and under a url.

Euler token list

Euler token list is updated with updateEulerList.js script, which is meant to be run with pm2

pm2 start ecosystem.config.js

The script:

• downloads a new Coingecko list,
• runs permit detection
• filters out tokens without Uniswap V3 WETH pair pools
• removes tokens from the euler list not present in the new list, unless there is an activated Euler market with that underlying
• updates existing token data if necessary
• adds new tokens if present
• applies curated overrides
• commits changes in git, pushes and creates a pull request in Github

For the last step, hub needs to be installed and configured.

Config

In addition to permit detection config, it is required to provide TOKENLIST_URL and PROCESSED_LIST_FILE_NAME (currently coingecko-tokenlist-with-permits.json). To automatically commit changes, UPDATE_REPO must be set to true. For Cloudwatch logging set up CLOUDWATCH_LOG_GROUP, CLOUDWATCH_LOG_STREAM and AWS_REGION.

Adding, removing and updating tokens manually

To manually add a token, put it in curated/add.js. If the token exists in the source list, the provided properties will be overwritten. Example updating the name of a token:

{
  "address": "0xc18360217d8f7ab5e7c516566761ea12ce7f9d72",
  "name": "Ethereum Name Service",
},

To remove a token from the list, add an entry in curated/remove.js

{
  "address": "0x9865af71cf0b288b4e7f654f4f7851eb46a2b7f8",
},