OnBridge token indexing engine and API server

In-browser Web3 JS library is not capable to extract transactions history natively. It's also pretty slow, especially on large lists. And it can be connected to just one network at a time (and bridge needs info from two networks at least).

To make user experience smoother we offload heavy background tasks to backend that indexes contract states and events on both L1 and L2 networks and makes correlation between bridging requests and transactions on both sides.

Build and Run API Server

This service is designed to be built and run using docker compose. Thus, you can also run it locally.

Step 1. Postgres

Before run Django project one should create Postgresql connection at port 5432 (docker image or service)
Create user onbridge with your password and also database onbridge and give to user permissions.

Example in postgres (This code is for cases when Postgres is not running in Docker)

psql
create database onbridge;
create user onbridge with encrypted password '<your db password>';
grant all privileges on database onbridge to onbridge;

Example of how to start Docker image of Postgres

docker pull postgres
docker run --rm --name db -p 5432:5432 -e POSTGRES_PASSWORD=<your db password> -e POSTGRES_USER=onbridge -e POSTGRES_DB=onbridge postgres

Step 2. Django project with API

Envs to runserver locally

ADMIN_USER=admin
ADMIN_PASSWORD=<your admin password>
DB_HOST=localhost
DB_NAME=onbridge
DB_USER=onbridge
DB_PASSWORD=<your db password>
SECRET_KEY=<your secret key>

Command

python3 -m venv venv
source venv/bin/activate
python3 manage.py migrate
python3 manage.py runserver

Or via docker

set -a; source <your file with envs>; set +a;
docker build -t api
docker run -it -e ADMIN_USER -e ADMIN_PASSWORD -e DB_HOST -e DB_NAME -e DB_USER -e DB_PASSWORD --network=host api

Step 3. Token indexers

Before starting indexers one should initialize token indexer's state: current block, chain id, etc.
For this one should run init_status_model.py with following envs:

BSC_CHAIN_ID=97
ETH_CHAIN_ID=42
POLYGON_CHAIN_ID=80001
BSC_START_BLOCK=16780489
ETH_START_BLOCK=29852491
POLYGON_START_BLOCK=24965926

Run this code with activated venv

python3 manage.py migrate
python3 init_status_model.py

It is recommended to have a proper .env-file for each indexer.
One indexer checks only one chain
Contents of such chain env file:

UPSTREAM=<rpc provider url>
TOKEN_ABI_FILENAME=token_indexer/erc721-abi.json
TOKEN_ADDRESS=<address of token on this chain>
BRIDGE_ADDRESS=<address of bridge contract on this chain>
INDEXER_INTERVAL=<interval of indexer in seconds>
IPFS_HOST='https://ipfs.io'

ADMIN_USER=admin
ADMIN_PASSWORD=<your admin password>
DB_HOST=localhost
DB_NAME=onbridge
DB_USER=onbridge
DB_PASSWORD=<your db password>
SECRET_KEY=<your secret key>

Run this code with activated venv

set -a;
source <file with envs for specific chain>;
set +a;
python3 token_indexer/start.py

Note: it is recommended to run L1 indexer firstly

Unless all tokens at L1 chain are written to database other indexers should be shut down.
If we run L1 and L2 indexer in concurrent mode, there can be errors.

Envs from ADMIN_USER to SECRET_KEY are the same for all indexers (since they are Django project envs). Others are describes bellow:

BSC

UPSTREAM=https://data-seed-prebsc-1-s1.binance.org:8545/
TOKEN_ABI_FILENAME=token_indexer/erc721-abi.json
TOKEN_ADDRESS=0xe6847645B1832B2923e5938ec482f2b0EfA6DE4c
BRIDGE_ADDRESS=0x099e3307be3b694e8C7dBc54E2ecB8897806BD2A
INDEXER_INTERVAL=3
IPFS_HOST='https://ipfs.io'

Kovan

UPSTREAM=https://kovan.infura.io/v3/<your infura key>
TOKEN_ABI_FILENAME=token_indexer/erc721-abi.json
TOKEN_ADDRESS=0x45c037263752F1d1F8cA94fAff339A0178C06EEb
BRIDGE_ADDRESS=0xBa32a080612eA433FD64F4C5c99c73666149e997
INDEXER_INTERVAL=3
IPFS_HOST='https://ipfs.io'

Polygon

UPSTREAM=https://matic-mumbai.chainstacklabs.com/
TOKEN_ABI_FILENAME=token_indexer/erc721-abi.json
TOKEN_ADDRESS=0xc303c254529542bfCbCCE275Bb8c819fD8fFdb03
BRIDGE_ADDRESS=0xF6C9DaF74f99388c2C666b0468a9f1D1601c0013
INDEXER_INTERVAL=3
IPFS_HOST='https://ipfs.io'

LICENSE

OnBridge - NFT bridge for advanced GameFi mechanics
Copyright (C) 2021 OnBridge.IO

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <https://www.gnu.org/licenses/>.