Missing parameter for API: PayInvoice, PayOffer, SendToNode, SendToRoute

[DerEwige]

Internal function like

fr.acinq.eclair.EclairImpl.findRouteBetween
fr.acinq.eclair.EclairImpl.findRoute

offer a Boolean to control if local fees should be included
boolean includeLocalChannelCost

This option is missing from all APIs that let you set maximum Fees:

PayInvoice
PayOffer
SendToNode
SendToRoute

Furthermore, many of those APIs offer the parameter maxFeePct.
A parameter maxFeePPM would make much more sense so one could set fees smaller than 10'000 ppm (1 %)

[thomash-acinq]

includeLocalChannelCost is an internal thing, I don't see why the user would need to pay fees to themselves.
And for setting fees smaller than 1%, just set maxFeePct to a value that's less than 1: --maxFeePct=0.05 for instance. It's just that percentages are more common in daily life so should be more familiar to the user than ppm.

[DerEwige]

includeLocalChannelCost is an internal thing, I don't see why the user would need to pay fees to themselves.

every sensible node oeprator is aware of ones own fee.
I don't want a payment to go through my loop channel and then back down to boltz and waste my precious sats in the loop channel that are priced for 5000 ppm when I can reach boltz for 2000 ppm through many of my other channels.

And for setting fees smaller than 1%, just set maxFeePct to a value that's less than 1: --maxFeePct=0.05 for instance. It's just that percentages are more common in daily life so should be more familiar to the user than ppm.

maxFeePct only accepts integers only 1 or 0 is possible 0.05 is not a valid input

[thomash-acinq]

maxFeePct is a double, not an integer. I've just tried --maxFeePct=0.05 and it parsed it well.

[DerEwige]

maxFeePct is a double, not an integer. I've just tried --maxFeePct=0.05 and it parsed it well.

ok then this part is just a documentation error:

https://acinq.github.io/eclair/#payinvoice

[DerEwige]

what about includeLocalChannelCost?
Will you include it, or do I have to make own API end point through a plugin to support it?

edit: I probably just change this line of code to true and rebuild
https://github.com/ACINQ/eclair/blob/235e95df8f7a549f02d871cf9cafc3fc919638c9/eclair-core/src/main/scala/fr/acinq/eclair/router/Router.scala#L367C33-L367C38

[thomash-acinq]

We'll fix the documentation, thanks for noticing it.
Regarding includeLocalChannelCost, I still don't think it should be exposed to the user. You can obviously build a custom version, and I think changing that one line should work. Many people seem to think that their liquidity to LOOP (or any other big sink node) is worth more than the liquidity to other nodes, however it costs you the same to open a channel to any node (actually you're probably opening larger channels to LOOP, so it costs you less per sat in the channel).

[DerEwige]

It is the way how routing nodes think.

You sell your liquidity to other nodes and then replenish that liquidity for a price below that.
It is the only income stream for a pure routing node.

When you sell a service, that income stream drops into the background.
For example I would classify the ACINQ node as a Gateway or Service node.
Your 500 ppm fee fall makes it very clear, that you are not interested into being a routing node.

But the network needs routing nodes, without routing nodes the network won’t work.

As a routing node operator myself I can say this:
There is not a single use-case where I would ignore my local fees.

I already built the custom version with the changed line.
It works exactly as I anticipated and it is exactly what I need.

For me personally this issue is resolved.
But I still think it would be useful for other users.

[t-bast]

I don't think includeLocalChannelCost should be exposed at the RPC layer, I agree with @thomash-acinq here.

If that is helpful for some custom node operator logic that monitors channel activity and decides how to update relay fees or which channels to open/close, this is definitely something that should be done in a plugin (which is, I believe, the way you're doing it). Plugins can set this parameter, so they shouldn't need any change?

[DerEwige]

Yes. I do my channel management through plugins.
This includes but is not limited to automatic fee settings and circular rebalancing.

Those are things that I consider part of my lightning node.

But I also do stuff like liquidity management by automatically depositing and withdrawing bitcoin from multiple exchanges.
I do not consider this a core functionality of my node and do not want it to be integrated via plugin.
It is a separate demon that connects to the node via API.
But I still need this external daemon to respect my local fees.

I have already built a custom version with this line set to true:
https://github.com/ACINQ/eclair/blob/235e95df8f7a549f02d871cf9cafc3fc919638c9/eclair-core/src/main/scala/fr/acinq/eclair/router/Router.scala#L367C33-L367C38

This works exactly as I expected and suites my needs.