This commit finally enables MP payments within the payment lifecycle
(used for SendPayment). This is done by letting the loop launch shards
as long as there is value remaining to send, inspecting the outcomes for
the sent shards when the full payment amount has been filled.
The method channeldb.MPPayment.SentAmt() is added to easily look up how
much value we have sent for the payment.
This commit redefines how the control tower handles shard and payment
level settles and failures. We now consider the payment in flight as
long it has active shards, or it has no active shards but has not
reached a terminal condition (settle of one of the shards, or a payment
level failure has been encountered).
We also make it possible to settle/fail shards regardless of the payment
level status (since we must allow late shards recording their status
even though we have already settled/failed the payment).
Finally, we make it possible to Fail the payment when it is already
failed. This is to allow multiple concurrent shards that reach terminal
errors to mark the payment failed, without havinng to synchronize.
To move towards how we will handle existing attempt in case of MPP
(collecting their outcome will be done in separate goroutines separate
from the payment loop), we move to collect their outcome first.
To easily fetch HTLCs that are still not resolved, we add the utility
method InFlightHTLCs to channeldb.MPPayment.
This commit extends the htlc fail info with the full failure reason that
was received over the wire. In a later commit, this info will also be
exposed on the rpc interface. Furthermore it serves as a building block
to make SendToRoute reliable across restarts.
This commit converts the database structure of a payment so that it can
not just store the last htlc attempt, but all attempts that have been
made. This is a preparation for mpp sending.
In addition to that, we now also persist the fail time of an htlc. In a
later commit, the full failure reason will be added as well.
A key change is made to the control tower interface. Previously the
control tower wasn't aware of individual htlc outcomes. The payment
remained in-flight with the latest attempt recorded, but an outcome was
only set when the payment finished. With this commit, the outcome of
every htlc is expected by the control tower and recorded in the
database.
Co-authored-by: Johan T. Halseth <johanth@gmail.com>
To better distinguish payments from HTLCs, we rename the attempt info
struct to HTLCAttemptInfo. We also embed it into the HTLCAttempt struct,
to avoid having to duplicate this information.
The paymentID term is renamed to attemptID.
