Maker Backend & Taker Frontend: Implement swaps

[yosriady]

Technical specs

The Node.js backend API is responsible for making BTC-DAI offers for the user and proceed with the swap if someone takes the offer from the desktop client.

This task implements:

• Running a Bitcoin and Ethereum node as the maker, using the SDK (?)
• Accepts swap requests
• Executes swap requests

I'm not yet clear of which of the functionality is already implemented by the SDK and which needs to be implemented.

Definition of Done

• Users can submit a swap request to the maker.
• Users can perform a swap with the maker (to be expanded.)

Phase 1

**TODOs** - [x] Evaluate browser wallet integration / walletconnect - [ ] ~~Grok `EthereumWallet` SDK interface under the hood to evaluate integration with Ledger / other wallets~~ Halting wallet integration - [ ] ~~Research injecting providers for ledger support https://github.com/MetaMask/web3-provider-engine~~ Extracted to issue - [x] Go through https://comit.network/docs/getting-started/create-comit-app/ - [ ] Set up infra for maker backend - [ ] ~~Run Bitcoin and Ethereum nodes for the service (locally)~~ Halting node setup - [ ] Go through https://github.com/comit-network/create-comit-app/tree/master/scripts to run nodes locally (separate pairs) for maker backend and for desktop app - [x] Set up https://en.bitcoin.it/wiki/Bitcoind - [x] https://github.com/bitcoin/bitcoin/blob/master/doc/build-osx.md - `./src/bitcoind` / `./src/bitcoin-cli stop` - [x] Grok `InMemoryBitcoinWallet` config parameters https://github.com/bcoin-org/bcoin/blob/master/docs/README.md - [x] https://medium.com/@bitstein/setting-up-a-bitcoin-lightning-network-test-environment-ab967167594a - [x] Clarify about 'regtest` network and what it affects - [ ] Grok https://github.com/bitcoin/bitcoin/blob/master/share/examples/bitcoin.conf - rpc settings - [x] Create bitcoin.conf with the following config https://github.com/comit-network/create-comit-app/blob/master/scripts/src/docker/bitcoin.rs#L52-L62 - [ ] Set up Ganache locally for Ethereum (URI, private key, erc20 contract address) - [ ] Set up `cnd` locally - [ ] configure `.env` in its proper directory under `maker/` - [ ] ~~Evaluate hosted services for nodes e.g. https://alchemyapi.io/infrastructure~~ Extracted to issue - [ ] Config environment variables - ~~`~/.create-comit-app/env` is bad DX, is there a way to configure where the env should live? Right now, developers cannot use `comit-scripts` for anything other than running the example.~~ Not meant for actual use - [ ] ~~Once Bitcoin and Ethereum infra is set up,~~ Proceeding with local nodes from `comit-scripts`, see below spec

TODOs Phase 2

• [x] Maker Backend
  • [x] Initialize Maker
  • [x] Create endpoint GET / (root) to display maker info e.g. peerId, addresshint for Frontend Taker to use to createSwap
  • [x] Create endpoint GET /swaps to return maker.comitClient.getNewSwaps()
  • [x] Grok Swap fetch function https://github.com/comit-network/comit-js-sdk/blob/9ab87203d0c204ea24c32312b1d485e4f4cea975/src/cnd/cnd.ts#L161
  • [x] State machine for Maker to do 'next' step when polling
  • [x] Spike and implement polling mechanism
  • [x] Needs to poll for taker.comitClient.sendSwap to be confirmed, and
  • [x] call makerSwapHandle.accept(...)
  • [x] Needs to poll for takerSwapHandle.fund(...) to be confirmed, and
  • [x] call makerSwapHandle.fund(...)
  • [x] Needs to poll for takerSwapHandle.redeem(...) to be confirmed, and call:
  • [x] makerSwapHandle.redeem
• [x] Taker Frontend
  • [x] Initialize Taker
  • [x] SwapForm submit should createSwap and,
  • [ ] (Optional) Implement a confirmation modal
  • [x] sendSwap
  • [x] Implement SwapList component for HomePage
  • [x] Implement SwapDetailsPage to display status and info of a single swap and perform next steps
    • Automated with useEffect? Or manual / user-initiated?
  • [x] State machine for Taker to do 'next' step when polling
  • [x] Spike and implement polling mechanism
  • [x] Needs to poll for makerSwapHandle.accept(...) to be confirmed, and call:
  • [x] takerSwapHandle.deploy(...)
  • [x] takerSwapHandle.fund(...)
  • [x] Needs to poll for makerSwapHandle.fund(...) to be confirmed, and call:
  • [x] takerSwapHandle.redeem
  • [x] Needs to poll for makerSwapHandle.redeem(...) to be confirmed, and:
  • [x] let user know that the swap is done
• [ ] Debug bitcoin balances not displaying correctly Split into separate issue
• [x] Update README to describe architecture and setup instructions (Maker & poller, Taker, etc.)
• [x] Final round of cleanup and refactoring beforge merging to master
  • [ ] Taker: Refactor MAKER_URL to application-level .env Deferred to separate issue
  • [ ] Refactor taker & maker state machines into its own class with data + functions Deferred to separate issue
    • runTakerNextStep and parseTakerSwapStatus
  • [x] Address all remaining inline TODOs

Open Questions

• [ ] Should the desktop app also have its own backend instead of having the app call the COMIT SDK?
  • especially for monitoring transactions?
• [ ] Monitoring maker & taker confirmations Swap.fetchDetails returns status for: swap, alpha & beta ledgers, communication
  • [ ] Implement or use a third-party service e.g. AlchemyAPI
  • [ ] SDK may need to return transaction ID on functions that perform a transaction, for async monitoring purposes Available in Swap object

[D4nte]

• Running a Bitcoin and Ethereum node as the maker, using the SDK (?)

Hi @yosriady, just to be sure we are on the same page. We prefer that you tell us (or you open PRs) to update the SDK so it's usable than not using the SDK 🙂

[yosriady]

@D4nte

Are developers supposed to use comit-scripts to manage their production nodes? Since it was part of create-comit-app and not comit-sdk, I thought it was more for running a development environment to run the examples.

For a production-ready setup, wouldn't developers need to run their own nodes? Maybe I'm missing something here. I don't see how you can run a Bitcoin and Ethereum node using the SDK. 🤔

[bonomat]

Really good question: comit-script should just help to spin up a developer environment and the comit-sdk does not concern the environment at all.

For a production-ready setup a developer would need to provide their own nodes.