Payments exceeding outbound liquidity take a long time to fail

[dangeross]

When attempting to pay an invoice that exceeds the outbound liquidity of the node, after a long interval the payment eventually times out. Ideally the payment would immediately fail if the node is unable to pay the invoice because of insufficient funds.

Below is an example of a node with an outbound liquidity of 15000 sats trying to pay a 100000 sat invoice and timing out after 150 seconds.

send_payment lnbc1m1pjuulkupp5jh6sheu7cnftf02kd7226xxhdnsg83870l02cgwyvxjuxyvta6lsdqqcqzzsxqrrssrzjqvgptfurj3528snx6e3dtwepafxw5fpzdymw9pj20jj09sunnqmwpapyqqqqqqq005qqqqlgqqqqqqgq9qsp5euqp9hjkg96jaqa78wg9qw7xnqq04vntt0kgsrydh9us2fvhtugs9qyyssqw575vy833rezpjzq92sezgqcz8mngxwdadd7lfqsecednk7gktzhpd9zf7r8czhx5s79nywseppfq3zvayevzq7ep5jh4tpdjr2e8pgp58vx5f

Error: Payment timeout: status: Unknown, message: "Error calling method Pay: RpcError { code: Some(210), message: \"Ran out of routes to try after 31 attempts: see `paystatus`\", data: None }", details: [], metadata: MetadataMap { headers: {"content-type": "application/grpc", "date": "Thu, 15 Feb 2024 21:36:45 GMT", "content-length": "0"} }

sdk-20240215.log

[cdecker]

Yes, we should likely do a pre-flight check. I'll see if I can

• [ ] Add it to the gl-plugin
• [ ] Downstream that pre-flight check into CLN

[cdecker]

This has been addressed with the pre-flight checks:

• If there is not enough capacity in channels we return immediately
• If we cannot get enough capacity online we return after a timeout of 30s, or proceed to pay if we can get it online.