Dump signed transactions for manual resolution

[TorstenStueber]

As a security measure we need to store all signed transactions that will be executed throughout the offramping flow on the backend at the beginning of the flow.

Reasoning

The user could close their browser at any point in time (see https://github.com/pendulum-chain/vortex/issues/57), however, for extra security we need to store all signed transactions on our backend as well. This should happen right at the beginning of the flow.

There is no need to implement any logic that deals with this data – it will only be used for manually completing the offramping flow.

TODO

• create and sign all transactions for our ephemeral accounts right at the beginning of the flow, before we even execute the first Polygon-related transaction, i.e.,
  • for Pendulum
  • approval for Nabla
  • swap on Nabla
  • Spacewalk redeem
  • on Stellar
  • offramp transaction
  • cleanup transaction
• send these transactions to the backend along with the public key of the user's Polygon account
• on the backend store the transactions with the public key and a timestamp, that can be used to uniquely identify the offramping operation

Open Questions

How to store the transactions? We should do this with the least amount of effort, i.e., we won't require a full fledged database if there is a simpler solution. A "write only memory" is enough, e.g., an append only log, etc.

[TorstenStueber]

Hey team! Please add your planning poker estimate with Zenhub @b-yap @bogdanS98 @ebma @gianfra-t

[gianfra-t]

Dumping them into a JSON (one and append or multiple and then prune every X time) would be the simplest, but redis is also quite easy to use. It can also be used as cache (assuming the node back-end).

[ebma]

We could also append the data to a Google sheet or similar. Then we don't even need to host anything.

[TorstenStueber]

I like a solution where we don't need to deploy our own infrastructure, so I prefer a Google sheet over our own Redis.

[gianfra-t]

I think a google sheet could work also, of course. But why a google sheet and not a more standard format like a .csv? Is it so we can directly read it ?

[TorstenStueber]

Where do you want to store the csv file, GDrive?

[gianfra-t]

No, locally on the backend then read it/fetch it from endpoint. But I viewed the google sheet docs and seems cleaner.

[ebma]

Closing this now that #79 is merged.