Use the peerswaprpc proto file for shared serialization

[YusukeShimizu]

This is for #134.
This change is the serialization part for peerswapd and the cln-plugin.
I use the peerswaprpc proto file for shared serialization.

The following changes will be made.

• differences in the struct's json tags.
• short channel id and state for PeerSwapPeerChannel is converted to channel id and active.

Important

We plan to merge after the stable release of v4.0. This is crucial information necessary for users to succeed.

[wtogami]

I didn't expect anyone to work on this ticket. This is very late right before a release. Are you sure this change has no impact on how things currently behave?

[YusukeShimizu]

No, this change may affect cln plugin behavior.

[wtogami]

• We want to do a stable release soon so we don't want to change anything big in the short-term.
• This will result in API changes.
• The premium feature will require API changes.
• So it's best to merge this along with other API changes so other applications don't need to change more than once.

[nepet]

Hey @YusukeShimizu,

You definitely got the idea what #134 is about and your execution so far is exactly what I was hoping for.

This PR gives us the opportunity to clean up some technical dept and serialization overhead and allows us to revisit the API and how it is accessed by humans. I expect most comments and discussions to be about field names and values while you streamline the API.

All of that being said, as we are close to a release, we might want to wait postpone merging this PR until the transition to the peerswaprc messages is fully completed. I do not expect the API to change that much, if at all in the meantime.

Cheers!

[nepet]

Maybe a scid it is more intuitive and "human readable". Do you think it makes sense to update the proto message

peerswap/peerswaprpc/peerswaprpc.proto

Lines 152 to 157 in 3201594

	message PeerSwapPeerChannel {
	uint64 channel_id = 1;
	uint64 local_balance = 2;
	uint64 remote_balance = 3;
	bool active = 5;
	}

to take a scid (string) instead of a channel id?

[YusukeShimizu]

I think there is a concern that replacing the channel id with a short channel id would be a breaking change and have a impact.
I think there will be a no problem if both channel id and short channel id are set, so I just add a short channel id.
de30b18

[nepet]

Internally we use the scid so there should no be a problem here. Changing from channel_id to scid would "break" the api that is just consumed by peerswapcli and maybe RTL so far. Vice versa for a change from scid to channel_id on the core-lightning plugin. We either way have to go with on change on the user facing api 😅

[YusukeShimizu]

Sorry, this may have caused a little confusion, so I will state it again.

I considered the following two way.
I personally believe that 1 is the way that will have the least impact, which do you think better?

1. Add string short_channel_id = 6;.
   The current change(de30b18) does this.

message PeerSwapPeerChannel {
    uint64 channel_id = 1;
    uint64 local_balance = 2;
    uint64 remote_balance = 3;
    bool active = 5;
    string short_channel_id = 6;
}

2. Update uint64 uint channel_id = 1; to string short_channel_id = 1;

message PeerSwapPeerChannel {
    string short_channel_id = 1;
    uint64 local_balance = 2;
    uint64 remote_balance = 3;
    bool active = 5;
}

[YusukeShimizu]

All of that being said, as we are close to a release, we might want to wait postpone merging this PR until the transition to the peerswaprc messages is fully completed. I do not expect the API to change that much, if at all in the meantime.

I understand the above.
I will keep the PR in draft status until merge is available.
Please let me know if there is a proper way to operate it.