Lending App example

[sidmore]

Title: Implement Lending Protocol with Collateralized Borrowing and Liquidity Management

Overview

This PR introduces the core functionality for a decentralized lending protocol, including:

Collateralized Lending:
Users can deposit BTC and ETH as collateral to borrow USDT.
Borrowing limits are enforced using a configurable collateral factor.

Liquidity Pool Management:
Separate liquidity pools for BTC and ETH.
Users can add or remove liquidity, and interest rewards are distributed as DEFI tokens.

Wallet Management:
Users can deposit, withdraw, and query their wallet balances for supported tokens (BTC, ETH, USDT, and DEFI).

Interest Accrual:
Liquidity providers earn DEFI tokens as interest, distributed proportionally based on their contribution to the pools.

Major Changes

Endpoints:
depositTokenEndpoint: Deposit tokens into the user's wallet.
withdrawTokenEndpoint: Withdraw tokens from the user's wallet.
getWalletBalanceEndpoint: Retrieve wallet balance for a specific token.
addCollateralEndpoint: Deposit tokens as collateral.
borrowEndpoint: Borrow USDT tokens against collateral.
removeLiquidityEndpoint: Withdraw liquidity from BTC or ETH pools.

Modules:
Wallet Module:
depositToken: Adds tokens to a user's wallet.
withdrawToken: Deducts tokens from a user's wallet.

Lending Module:
addCollateral: Manages collateral deposits for borrowing.
borrow: Validates collateral, withdraws tokens from liquidity, and credits them to the user's wallet.
removeLiquidity: Allows users to withdraw their liquidity from the pool.

Liquidity Pools:
Added poolTable to manage BTC and ETH pools.
Tracks totalLiquidity and user contributions for each token.

Workflow Examples

Adding Liquidity:
User deposits 2 BTC into the BTC pool using addLiquidity.
The pool's total liquidity increases, and the user's contribution is tracked.

Borrowing Tokens:
User with sufficient BTC collateral borrows 1000 USDT.
Tokens are deducted from the USDT pool and credited to the user's wallet.

Interest Accrual:
Liquidity providers in BTC and ETH pools earn DEFI tokens proportional to their contributions.

Wallet Operations:
Users can deposit, withdraw, or query their wallet balances for supported tokens.

Configuration

Collateral Factor: Configurable via COLLATERAL_FACTOR (default: 1.5).
Base Interest Rate: Configurable via BASE_RATE (default: 2% per period).
Key Features
DeFi Standards:
Aligns with real-world DeFi protocols like Aave, enabling collateralized borrowing and interest distribution.
Scalable Design:
Modular structure with separate modules for wallet, lending, and liquidity pool management.
Security and Validation:
Comprehensive input validation and error handling in all endpoints.

[ivarprudnikov]

why liquidityPools endpoints not imported?

[ivarprudnikov]

An explanation how to use it would be great as it would make the whole example standalone.

[ivarprudnikov]

Are these endpoints correct? lending.ts has only 2 methods exported

[sidmore]

will update the lending.ts as i forgot to add endpt to remove collateral and remove liquidity

[ivarprudnikov]

scripts section is missing, I would expect some basic ones such as build or test

[sidmore]

let me add the build script to generate app.json

[ivarprudnikov]

I could not start it as there is a missing config it seems:

# start the ccf sandbox container ...
docker run --rm -it --entrypoint=/bin/bash -v `pwd`:/app ghcr.io/microsoft/ccf/app/dev/virtual:ccf-5.0.0

# install nodejs
curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash - && sudo apt-get install -y nodejs

# build the app
cd /app/lending-app
npm i
npx tsc

# run the app
/opt/ccf_virtual/bin/sandbox.sh --js-app-bundle ./dist/

ends up with the error:

[12:30:10.430] Starting 1 CCF node...
Traceback (most recent call last):
  File "/opt/ccf_virtual/bin/start_network.py", line 221, in <module>
    run(args)
  File "/opt/ccf_virtual/bin/start_network.py", line 94, in run
    network.start_and_open(args)
  File "/opt/ccf_virtual/bin/infra/network.py", line 640, in start_and_open
    self.open(args)
  File "/opt/ccf_virtual/bin/infra/network.py", line 607, in open
    self.consortium.set_js_app_from_dir(
  File "/opt/ccf_virtual/bin/infra/consortium.py", line 560, in set_js_app_from_dir
    bundle = self.read_bundle_from_dir(bundle_path)
  File "/opt/ccf_virtual/bin/infra/consortium.py", line 542, in read_bundle_from_dir
    with open(metadata_path, encoding="utf-8") as f:
FileNotFoundError: [Errno 2] No such file or directory: './dist/app.json'

[sidmore]

I could not start it as there is a missing config it seems:

# start the ccf sandbox container ...
docker run --rm -it --entrypoint=/bin/bash -v `pwd`:/app ghcr.io/microsoft/ccf/app/dev/virtual:ccf-5.0.0

# install nodejs
curl -fsSL https://deb.nodesource.com/setup_18.x | sudo -E bash - && sudo apt-get install -y nodejs

# build the app
cd /app/lending-app
npm i
npx tsc

# run the app
/opt/ccf_virtual/bin/sandbox.sh --js-app-bundle ./dist/

ends up with the error:

[12:30:10.430] Starting 1 CCF node...
Traceback (most recent call last):
  File "/opt/ccf_virtual/bin/start_network.py", line 221, in <module>
    run(args)
  File "/opt/ccf_virtual/bin/start_network.py", line 94, in run
    network.start_and_open(args)
  File "/opt/ccf_virtual/bin/infra/network.py", line 640, in start_and_open
    self.open(args)
  File "/opt/ccf_virtual/bin/infra/network.py", line 607, in open
    self.consortium.set_js_app_from_dir(
  File "/opt/ccf_virtual/bin/infra/consortium.py", line 560, in set_js_app_from_dir
    bundle = self.read_bundle_from_dir(bundle_path)
  File "/opt/ccf_virtual/bin/infra/consortium.py", line 542, in read_bundle_from_dir
    with open(metadata_path, encoding="utf-8") as f:
FileNotFoundError: [Errno 2] No such file or directory: './dist/app.json'

will fix thanks for catching it