emit hex encoded ack attribute in events (#197)

* emit hex encoded ack in events

* add changelog and update migration docs

CHANGELOG.md

@@ -70,6 +70,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 * (07-tendermint) [\#182](https://github.com/cosmos/ibc-go/pull/182) Remove duplicate checks in upgrade logic.
 * (modules/core/04-channel) [\#7949](https://github.com/cosmos/cosmos-sdk/issues/7949) Standardized channel `Acknowledgement` moved to its own file. Codec registration redundancy removed.
 * (modules/core/04-channel) [\#144](https://github.com/cosmos/ibc-go/pull/144) Introduced a `packet_data_hex` attribute to emit the hex-encoded packet data in events. This allows for raw binary (proto-encoded message) to be sent over events and decoded correctly on relayer. Original `packet_data` is DEPRECATED. All relayers and IBC event consumers are encouraged to switch to `packet_data_hex` as soon as possible.
+* (core/04-channel) [\#197](https://github.com/cosmos/ibc-go/pull/197) Introduced a `packet_ack_hex` attribute to emit the hex-encoded acknowledgement in events. This allows for raw binary (proto-encoded message) to be sent over events and decoded correctly on relayer. Original `packet_ack` is DEPRECATED. All relayers and IBC event consumers are encouraged to switch to `packet_ack_hex` as soon as possible.
 * (modules/light-clients/07-tendermint) [\#125](https://github.com/cosmos/ibc-go/pull/125) Implement efficient iteration of consensus states and pruning of earliest expired consensus state on UpdateClient.
 * (modules/light-clients/07-tendermint) [\#141](https://github.com/cosmos/ibc-go/pull/141) Return early in case there's a duplicate update call to save Gas.
 

docs/migrations/ibc-migration-043.md

@@ -110,6 +110,8 @@ The `OnRecvPacket` callback has been modified to only return the acknowledgement
 
 The `packet_data` attribute has been deprecated in favor of `packet_data_hex`, in order to provide standardized encoding/decoding of packet data in events. While the `packet_data` event still exists, all relayers and IBC Event consumers are strongly encouraged to switch over to using `packet_data_hex` as soon as possible.
 
+The `packet_ack` attribute has also been deprecated in favor of `packet_ack_hex` for the same reason stated above. All relayers and IBC Event consumers are strongly encouraged to switch over to using `packet_ack_hex` as soon as possible.
+
 The `consensus_height` attribute has been removed in the Misbehaviour event emitted. IBC clients no longer have a frozen height and misbehaviour does not necessarily have an associated height.
 
 ## Relevant SDK changes

modules/core/04-channel/keeper/packet.go

@@ -381,6 +381,7 @@ func (k Keeper) WriteAcknowledgement(
 			sdk.NewAttribute(types.AttributeKeyDstPort, packet.GetDestPort()),
 			sdk.NewAttribute(types.AttributeKeyDstChannel, packet.GetDestChannel()),
 			sdk.NewAttribute(types.AttributeKeyAck, string(acknowledgement)),
+			sdk.NewAttribute(types.AttributeKeyAckHex, hex.EncodeToString(acknowledgement)),
 			// we only support 1-hop packets now, and that is the most important hop for a relayer
 			// (is it going to a chain I am connected to)
 			sdk.NewAttribute(types.AttributeKeyConnection, channel.ConnectionHops[0]),

modules/core/04-channel/types/events.go

@@ -23,9 +23,11 @@ const (
 
 	// NOTE: DEPRECATED in favor of AttributeKeyDataHex
 	AttributeKeyData = "packet_data"
+	// NOTE: DEPRECATED in favor of AttributeKeyAckHex
+	AttributeKeyAck = "packet_ack"
 
 	AttributeKeyDataHex          = "packet_data_hex"
-	AttributeKeyAck              = "packet_ack"
+	AttributeKeyAckHex           = "packet_ack_hex"
 	AttributeKeyTimeoutHeight    = "packet_timeout_height"
 	AttributeKeyTimeoutTimestamp = "packet_timeout_timestamp"
 	AttributeKeySequence         = "packet_sequence"