Support passing required config values via environment variables

[Luke-Rogerson]

What's this?

Support passing required config values via environment variables (needed for v3 architecture), in addition to config file.

Testing

Unit tests

Run npx ava --verbose --timeout=10m --serial --fail-fast src/cli-args.test.ts

Running locally

No config file and no environment variables

1. Run npx tsc --skipLibCheck -p ./tsconfig.prod.json && npm run start

Environment variables and no config file

1. Add the following env vars:

   export ETHEREUM_ENDPOINT=https://mainnet.infura.io/v3/123
   export NODE_ADDRESS=55555555d4bbbe34b470f12cb0e2cd2387f6710ec5815733005bc887c317e8cf

2. Run npx tsc --skipLibCheck -p ./tsconfig.prod.json && npm run start

Config file and no environment variables

1. Ensure previous env vars are not set:

   unset ETHEREUM_ENDPOINT
   unset NODE_ADDRESS

2. Create config.json in root of project with following:

   {
   "EthereumEndpoint": "https://mainnet.infura.io/v3/123",
   "MaticEndpoint": "https://polygon-mainnet.g.alchemy.com/v2/123",
   "node-address": "55555555d4bbbe34b470f12cb0e2cd2387f6710ec5815733005bc887c317e8cf"
   }

3. Run npx tsc --skipLibCheck -p ./tsconfig.prod.json && npm run start -- --config ./config.json