feat: implement send all onchain funds flag

refs fusion44#139

app/lightning/docs.py

@@ -99,6 +99,17 @@
 * If __sat_per_vbyte__ is set then __target_conf__ is ignored and vbytes (sipabytes) will be used.
 
 > 👉 See [https://lightning.readthedocs.io/lightning-txprepare.7.html](https://lightning.readthedocs.io/lightning-txprepare.7.html)
+
+### Sending all onchain funds
+> ℹ️ Keep the following points in mind when sending all onchain funds:
+
+* If __send_all__ is set to __true__, the __amount__ field must be set to __0__. 
+* If the __amount__ field is greater than __0__, the __send_all__ field must be __false__. 
+ * The API will return an error if neither or both conditions are met at the same time.
+* If __send_all__ is set to __true__ the amount of satoshis to send will be calculated by subtracting the fee from the wallet balance. 
+* If the wallet balance is not sufficient to cover the fee, the call will fail. 
+* The call will __not__ close any channels. 
+* The implementation may keep a reserve of funds if there are still open channels.
 """
 
 send_payment_desc = """

app/lightning/impl/cln_grpc.py

@@ -16,6 +16,7 @@
 import app.lightning.impl.protos.cln.primitives_pb2 as lnp
 from app.api.utils import config_get_hex_str, next_push_id
 from app.bitcoind.utils import bitcoin_rpc_async
+from app.api.utils import SSE, broadcast_sse_msg
 from app.lightning.impl.ln_base import LightningNodeBase
 from app.lightning.models import (
  Channel,
@@ -352,7 +353,7 @@ async def list_on_chain_tx(self) -> List[OnChainTransaction]:
 
  # TODO: Improve this once CLN reports the block height in bkpr-listincome
  # see https://github.com/ElementsProject/lightning/issues/5694
- 
+
  # now get the block height for each tx ...
  res = await _make_local_call("bkpr-listaccountevents")
  if not res:
@@ -567,7 +568,7 @@ async def send_coins(self, input: SendCoinsInput) -> SendCoinsResponse:
  utxos.append(lnp.Outpoint(txid=o.txid, outnum=o.output))
  max_amt += o.amount_msat.msat
 
- if max_amt <= input.amount:
+ if not input.send_all and max_amt <= input.amount:
  raise HTTPException(
  status.HTTP_412_PRECONDITION_FAILED,
  detail=f"Could not afford {input.amount}sat. Not enough funds available",
@@ -576,14 +577,17 @@ async def send_coins(self, input: SendCoinsInput) -> SendCoinsResponse:
  req = ln.WithdrawRequest(
  destination=input.address,
  satoshi=lnp.AmountOrAll(
- amount=lnp.Amount(msat=input.amount), all=False
+ amount=lnp.Amount(msat=input.amount),
+ all=input.send_all,
  ),
  minconf=input.min_confs,
  feerate=fee_rate,
  utxos=utxos,
  )
- res = await self._cln_stub.Withdraw(req)
- return SendCoinsResponse.from_cln_grpc(res, input)
+ response = await self._cln_stub.Withdraw(req)
+ r = SendCoinsResponse.from_cln_grpc(response, input)
+ await broadcast_sse_msg(SSE.LN_ONCHAIN_PAYMENT_STATUS, r.dict())
+ return r
  except grpc.aio._call.AioRpcError as error:
  details = error.details()
  if details and details.find("Could not parse destination address") > -1:

app/lightning/impl/lnd_grpc.py

@@ -8,6 +8,7 @@
 from fastapi.exceptions import HTTPException
 from starlette import status
 
+import app.bitcoind.service as btc
 import app.lightning.impl.protos.lnd.lightning_pb2 as ln
 import app.lightning.impl.protos.lnd.lightning_pb2_grpc as lnrpc
 import app.lightning.impl.protos.lnd.router_pb2 as router
@@ -503,14 +504,26 @@ async def send_coins(self, input: SendCoinsInput) -> SendCoinsResponse:
  sat_per_vbyte=input.sat_per_vbyte,
  min_confs=input.min_confs,
  label=input.label,
+ send_all=input.send_all,
  )
 
- response = await self._lnd_stub.SendCoins(r)
- r = SendCoinsResponse.from_lnd_grpc(response, input)
+ bi = await btc.get_blockchain_info()
+ sendResponse = await self._lnd_stub.SendCoins(r)
+ txResponse = await self._lnd_stub.GetTransactions(
+ ln.GetTransactionsRequest(start_height=-1, end_height=bi.blocks)
+ )
+
+ tx = None
+ for t in txResponse.transactions:
+ if t.tx_hash == sendResponse.txid:
+ tx = t
+ break
+
+ r = SendCoinsResponse.from_lnd_grpc(tx, input)
  await broadcast_sse_msg(SSE.LN_ONCHAIN_PAYMENT_STATUS, r.dict())
  return r
  except grpc.aio._call.AioRpcError as error:
- _check_if_locked()
+ _check_if_locked(error)
  details = error.details()
  if details and details.find("invalid bech32 string") > -1:
  raise HTTPException(

app/lightning/models.py

@@ -4,7 +4,7 @@
 
 from deepdiff import DeepDiff
 from fastapi.param_functions import Query
-from pydantic import BaseModel
+from pydantic import BaseModel, validator
 from pydantic.types import conint
 
 import app.lightning.docs as docs
@@ -1136,10 +1136,6 @@ class SendCoinsInput(BaseModel):
  ...,
  description="The base58 or bech32 encoded bitcoin address to send coins to on-chain",
  )
- amount: conint(gt=0) = Query(
- ...,
- description="The number of bitcoin denominated in satoshis to send",
- )
  target_conf: int = Query(
  None,
  description="The number of blocks that the transaction *should* confirm in, will be used for fee estimation",
@@ -1155,6 +1151,47 @@ class SendCoinsInput(BaseModel):
  label: str = Query(
  "", description="A label for the transaction. Ignored by CLN backend."
  )
+ send_all: bool = Query(
+ False,
+ description="Send all available on-chain funds from the wallet. Will be executed `amount` is **0**",
+ )
+ amount: conint(ge=0) = Query(
+ 0,
+ description="The number of bitcoin denominated in satoshis to send. Must not be set when `send_all` is true.",
+ )
+
+ @validator("amount", pre=True, always=True)
+ def check_amount_or_send_all(cls, amount, values):
+ if amount == None:
+ amount = 0
+
+ send_all = values.get("send_all") if "send_all" in values else False
+
+ if amount < 0:
+ raise ValueError("Amount must not be negative")
+
+ if amount == 0 and not send_all:
+ # neither amount nor send_all is set
+ raise ValueError(
+ "Either amount or send_all must be set. Please review the documentation."
+ )
+
+ if amount > 0 and not send_all:
+ # amount is set and send_all is false
+ return amount
+
+ if amount > 0 and send_all:
+ # amount is set and send_all is true
+ raise ValueError(
+ "Amount and send_all must not be set at the same time. Please review the documentation."
+ )
+
+ if amount == 0 and send_all:
+ # amount is not set and send_all is true
+ return amount
+
+ # normally this should never be reached
+ raise ValueError(f"Unknown input.")
 
 
 class SendCoinsResponse(BaseModel):
@@ -1167,16 +1204,22 @@ class SendCoinsResponse(BaseModel):
  ...,
  description="The number of bitcoin denominated in satoshis which where sent",
  )
+ fees: conint(ge=0) = Query(
+ None,
+ description="The number of bitcoin denominated in satoshis which where paid as fees",
+ )
  label: str = Query(
  "", description="The label used for the transaction. Ignored by CLN backend."
  )
 
  @classmethod
  def from_lnd_grpc(cls, r, input: SendCoinsInput):
+ amount = input.amount if input.send_all == False else r.amount
  return cls(
- txid=r.txid,
+ txid=r.tx_hash,
  address=input.address,
- amount=input.amount,
+ amount=abs(amount),
+ fees=r.total_fees,
  label=input.label,
  )