zoneconcierge: proof that a tx is in a block #234
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app/app.go
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| @@ -406,6 +407,10 @@ func NewBabylonApp( | |||
| scopedIBCKeeper, | |||
| ) | |||
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| tmClient, err := client.NewClientFromNode("tcp://localhost:26657") // create a Tendermint client for ZoneConcierge | |||
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Can we read the url from config? For example, maybe we can read config from client.toml like this here.
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Good point! Used the node URI in clientCtx for this 👍
app/app.go
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| @@ -406,6 +407,10 @@ func NewBabylonApp( | |||
| scopedIBCKeeper, | |||
| ) | |||
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| tmClient, err := client.NewClientFromNode("tcp://localhost:26657") // create a Tendermint client for ZoneConcierge | |||
| if err != nil { | |||
| panic(fmt.Errorf("couldn't get client from nodeURI: %v", err)) | |||
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Maybe not for this case but I would suggest we use %w to wrap an error. See here.
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Thanks. Didn't know this usage before!
| @@ -92,11 +92,16 @@ func (k Keeper) FinalizedChainInfo(c context.Context, req *types.QueryFinalizedC | |||
| bestSubmissionKey := ed.Key[0] | |||
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| // TODO: construct inclusion proofs | |||
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This can be removed, right?
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We still get 3 inclusion proofs to implement after this PR: ProofBlockInEpoch, ProofEpochEnded and ProofEpochSubmitted
| @@ -70,3 +73,8 @@ type EpochingKeeper interface { | |||
| GetHistoricalEpoch(ctx sdk.Context, epochNumber uint64) (*epochingtypes.Epoch, error) | |||
| GetEpoch(ctx sdk.Context) *epochingtypes.Epoch | |||
| } | |||
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| // TMClient is a Tendermint that allows to query tx inclusion proofs | |||
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| // TMClient is a Tendermint that allows to query tx inclusion proofs | |
| // TMClient is a Tendermint client that allows to query tx inclusion proofs |
| ) | ||
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| func (k Keeper) ProveTxInBlock(ctx sdk.Context, txHash []byte) (*tmproto.TxProof, error) { | ||
| if len(txHash) != sha256.Size { |
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Maybe a custom type can be created for the transaction hash. I would also expect that tendermint or cosmos would have a type for that.
Fixes BM-301
This PR implements
ProofTxInBlock, the proof that a tx is included in a block. It includes the prover and the verifier.Approach
To get this proof, ZoneConcierge module will need to maintain a Tendermint query client, and direct the client to make queries to itself, similar to BLS signer that submits txs to Babylon itself.
This is the only possible way to get the tx inclusion proof: Cosmos SDK does not provide APIs for querying the underlying Tendermint blockchain. Everything one can query from a Cosmos SDK-based chain is included in interface
ABCIApplicationServerdefined here. It does not include querying block or tx. This makes sense since Cosmos SDK does not make any assumption on the underlying consensus engine (e.g., one can implement its own blockchain and talks to Cosmos SDK by using the same set of APIs).Future work
One important task is to have an integration test that runs Babylon and CZ (including their Tendermint nodes), and tests the inclusion of a CZ timestamp. Currently, this PR only tests the inclusion of a tx with a
MsgSendmsg, and tests theFinalizedChainInfoquery with a mocked Tendermint client.