How to write acknowledgement (commitments) in the IBC module?

[livelybug]

Hello,

I have a question about the usage of the function Writing acknowledgments.

In the life cycle of a packet, there's a functionWriting acknowledgements.

After reading the PR about it, no suggestion on the integration was found.

Is there any suggested place to call the function Writing acknowledgments?
How about ibc-rs provides an option to call the function after this line?

Or it's suggested to call the function on the IBC app?

Thank you

[adizere]

Hello,

Is there any suggested place to call the function Writing acknowledgments?

I think writing acknowledgement (commitments) should be done as part of the method ChannelKeeper::store_packet_commitment. An example implementation is in the Mock Context:

https://github.com/informalsystems/ibc-rs/blob/8212fc8ebaa0a51fb45bc04cc656f42eab1cee68/modules/src/mock/context.rs#L674-L685

Let me know if this makes sense or further details would be of help!

[boern]

Hi,guys:
I think the best time is after the application layer callback interface returns the ACK and then writes the ACK to the chain. Please refer to icS26 and IBC-Go for details.

[adizere]

Hi,guys:
I think the best time is after the application layer callback interface returns the ACK and then writes the ACK to the chain. Please refer to icS26 and IBC-Go for details.

Thank you for your feedback.

I agree. The method I described earlier, ChannelKeeper::store_packet_commitment is consistent with your suggestion to use the ICS26-level handling logic. We call that logic ChannelKeeper.

[yito88]

I have a question about how to make an acknowledgment. I'm not sure that it is good to ask about it here.
I tried to use ibc_proto::ibc::core::channel::v1::Acknowledgement. However, it couldn't be serialized as that of ibc-go. Cosmos(gaiad) couldn't verify the ack.
https://github.com/cosmos/ibc-go/blob/457095517b7832c42ecf13571fee1e550fec02d0/modules/core/04-channel/types/acknowledgement.go#L58-L60

[adizere]

I have a question about how to make an acknowledgment. I'm not sure that it is good to ask about it here.
I tried to use ibc_proto::ibc::core::channel::v1::Acknowledgement. However, it couldn't be serialized as that of ibc-go. Cosmos(gaiad) couldn't verify the ack.
https://github.com/cosmos/ibc-go/blob/457095517b7832c42ecf13571fee1e550fec02d0/modules/core/04-channel/types/acknowledgement.go#L58-L60

Is this related to informalsystems/hermes#2105 ? If so, we'll have a look there.

[yito88]

It's not related to informalsystems/hermes#2105.
I mean I want to know how to encode/decode the acknowledgment like ibc-go.
In ibc-go, it is encoded as JSON. Then, ibc-go hashes the encoded value and stores it to the storage.
https://github.com/cosmos/ibc-go/blob/13df199d70c4e3bd55419182270413491ee8a6d1/modules/core/04-channel/types/acknowledgement.go#L61
I also have the same issue for ibc_proto::ibc::applications::transfer::v2::FungibleTokenPacketData.

[hu55a1n1]

Hi @yito88! We're currently working on ICS20 in informalsystems/hermes#1989. Here's how we are handling serde for PacketData -> https://github.com/informalsystems/ibc-rs/pull/1989/files#diff-8f9bde3d68bd2354e1fa18e322a80e0c6d0b595d6b281db282116f948b44b8d5R305

[yito88]

@hu55a1n1 Thank you for sharing!

[plafer]

Closing this as stale; if this is still an issue please open a new question in the discussion tab.