In this protocol we *can* actually have transactions with the same script, hence, we have to handle the `GetHistoryRes` by `Txid`.
To make this easier to understand we group the `Vec<Vec<GetHistoryRes>>` by `Txid` into `HashMap<Txid, GetHistroyRes>`.
Note: The assumption is, that only `GetHistroyRes` is returned for the `Txid`+`Script` combination.
The `Attestation` in the `oracle` module has `Desiarialization` rules that conflict with loading it from the db.
We should not reuse domain structs between modules anyway, so this was cleaned up by introducing a dedicated `model::Attestation` and mapping to `oracle::Attestation`.
- Handles the Oracle's attestation in the cfd actor, transition according to the knowledge we have about the timelock expiry already.
- Tries to publish the CET if we are in `CetStatus::Ready`, i.e. both the attestation and timelock expiry happened. We try publishing if either event happened, and just print a log in case it's not ready yet.
- Tries to re-publish CET if we are in `PendingCet` upon restart.
- Re-triggers CET monitoring upon startup.
- Extends any state after `ContractSetup` to be able to store the attestation. (see below for ideas to change that)
Things that could be done different:
Currently we are carrying on the attestation through a lot of states - because we cannot just transition the user to `OpenCommitted` because it is a user decision to go for commit, but we have to keep the attestation around once it happened.
To reduce the state complexity, we could store the attestation independent of the state, but associated with the cfd.
This would make things a lot simpler, but we would then always have to go to the database to check if the attestation is already around (which might make other parts more complex).
We can now pass more than one set of `nonce_pks` when creating a CFD.
Each set corresponds to (and is identified by) a different oracle
event, allowing us to construct CFDs which can be settled via oracle
attestation at more than one point in time.
We also remember the CET-event relationship in `CfdTransactions`. This
is needed so that we can select the correct CET when the oracle
attests to the outcome of an event. Additionally, we save the
`nonce_pks` to more easily verify the adaptor signatures.
This should greatly improve resilience as we no longer have any
tasks within `tokio` that can fail without recovering.
Instead, we periodically ping the actor with a `Sync` message which
updates the local state of all scripts and sends out messages accordingly.
This goes towards handling all cfd state transitions in one place, so it becomes easier to reason about it.
Currently, state transitions are scattered over the code of the cfd actor.
This change bundles the actual transition in the cfd itself.
Inserting the new state into the db is still in the responsibility of the caller.
note: the `monitor` import in `taker.rs` should technically not be part of this commit, but was needed because I decided that the `CfdMonitoringEvent` should live in the `monitor` actor. But since that is not part of the `Cfd` in `model` the taker needs to know about the `monitor`.
Daniel Karzel
Philipp Hoenisch
Lucas Soriano del Pino
Thomas Eizinger