How to deploy a dapp which uses multiple blockchain

Question

I am a newbie and started learning dapp on ethereum. Up till now, I wrote smart contracts; created frontend with html, css and js; deployed smart dapp on either private network(geth, ganache) or rinkeby testnet. I connected directly to blockchain via (frontend)js which is loaded by html pages.

Now,

I want to write a dapp that is deployed on two blockchain one private and one public i.e., certain data will be stored on private and rest will be stored on a public chain. The dapp should connect to these blockchain from backend Not from frontend. I have looked on the internet and found some sample of connecting a dapp from backend(nodejs) but I cannot find anything related with multi blockchain dapp. As far as i know, we configure our smart contract deployment configuration in "truffle-config.js" file. Now i need one group of contracts to be deployed on private chain and another group of contracts to be deployed on a public chain. Note that both groups are part of same dapp. What I want to know is:

How should i design this(please explain folder structure and truffle-config.js for multi deployment) ?

Will there be two web3 objects in backend(nodejs) ?

Is there any open source dapp that uses multiple blockchain?

Answer 1

There are some projects that are researching in the area

• Parity bridge connecting two ethereum blockchains https://github.com/paritytech/parity-bridge.

• Polkadot A more complex interactions with heterogeneous blockchains https://polkadot.network/#whatisit.

• A bridge for a specific project https://github.com/Giveth/giveth-bridge

But I don't know a general solution ready for production.