Mint: Fakewallet support for USD (#488)

* fakewallet usd wip

* FakeWallet support for USD

* fix api return for receive

* use MINT_BACKEND_BOLT11_SAT everywhere

.env.example

@@ -55,9 +55,9 @@ MINT_DERIVATION_PATH="m/0'/0'/0'"
 
 MINT_DATABASE=data/mint
 
-# Lightning
+# Funding source backends
 # Supported: FakeWallet, LndRestWallet, CoreLightningRestWallet, BlinkWallet, LNbitsWallet, StrikeUSDWallet
-MINT_LIGHTNING_BACKEND=FakeWallet
+MINT_BACKEND_BOLT11_SAT=FakeWallet
 
 # for use with LNbitsWallet
 MINT_LNBITS_ENDPOINT=https://legend.lnbits.com

.github/workflows/tests.yml

@@ -49,7 +49,7 @@ jobs:
           poetry-version: ${{ inputs.poetry-version }}
       - name: Run tests
         env:
-          MINT_LIGHTNING_BACKEND: FakeWallet
+          MINT_BACKEND_BOLT11_SAT: FakeWallet
           WALLET_NAME: test_wallet
           MINT_HOST: localhost
           MINT_PORT: 3337

Makefile

@@ -30,7 +30,7 @@ test:
 test-lndrest:
 	PYTHONUNBUFFERED=1 \
 	DEBUG=true \
-	MINT_LIGHTNING_BACKEND=LndRestWallet \
+	MINT_BACKEND_BOLT11_SAT=LndRestWallet \
 	MINT_LND_REST_ENDPOINT=https://localhost:8081/ \
 	MINT_LND_REST_CERT=../cashu-regtest-enviroment/data/lnd-3/tls.cert \
 	MINT_LND_REST_MACAROON=../cashu-regtest-enviroment/data/lnd-3/data/chain/bitcoin/regtest/admin.macaroon \

README.md

@@ -7,7 +7,7 @@
 
 *Disclaimer: The author is NOT a cryptographer and this work has not been reviewed. This means that there is very likely a fatal flaw somewhere. Cashu is still experimental and not production-ready.*
 
-Cashu is an Ecash implementation based on David Wagner's variant of Chaumian blinding ([protocol specs](https://github.com/cashubtc/nuts)). Token logic based on [minicash](https://github.com/phyro/minicash) ([description](https://gist.github.com/phyro/935badc682057f418842c72961cf096c)) which implements a [Blind Diffie-Hellman Key Exchange](https://cypherpunks.venona.com/date/1996/03/msg01848.html) scheme written down [here](https://gist.github.com/RubenSomsen/be7a4760dd4596d06963d67baf140406). The database mechanics in Cashu Nutshell and the Lightning backend uses parts from [LNbits](https://github.com/lnbits/lnbits-legend).
+Cashu is an Ecash implementation based on David Wagner's variant of Chaumian blinding ([protocol specs](https://github.com/cashubtc/nuts)). Token logic based on [minicash](https://github.com/phyro/minicash) ([description](https://gist.github.com/phyro/935badc682057f418842c72961cf096c)) which implements a [Blind Diffie-Hellman Key Exchange](https://cypherpunks.venona.com/date/1996/03/msg01848.html) scheme written down [here](https://gist.github.com/RubenSomsen/be7a4760dd4596d06963d67baf140406).
 
 <p align="center">
 <a href="#the-cashu-protocol">Cashu protocol</a> ·
@@ -169,12 +169,19 @@ You can find the API docs at [http://localhost:4448/docs](http://localhost:4448/
 # Running a mint
 This command runs the mint on your local computer. Skip this step if you want to use the [public test mint](#test-instance) instead.
 
-Before you can run your own mint, make sure to enable a Lightning backend in `MINT_LIGHTNING_BACKEND` and set `MINT_PRIVATE_KEY` in your `.env` file.
+## Docker
+
+```
+docker run -d -p 3338:3338 --name nutshell -e MINT_BACKEND_BOLT11_SAT=FakeWallet -e MINT_LISTEN_HOST=0.0.0.0 -e MINT_LISTEN_PORT=3338 -e MINT_PRIVATE_KEY=TEST_PRIVATE_KEY cashubtc/nutshell:0.15.2 poetry run mint
+```
+
+## From this repository
+Before you can run your own mint, make sure to enable a Lightning backend in `MINT_BACKEND_BOLT11_SAT` and set `MINT_PRIVATE_KEY` in your `.env` file.
 ```bash
 poetry run mint
 ```
 
-For testing, you can use Nutshell without a Lightning backend by setting `MINT_LIGHTNING_BACKEND=FakeWallet` in the `.env` file.
+For testing, you can use Nutshell without a Lightning backend by setting `MINT_BACKEND_BOLT11_SAT=FakeWallet` in the `.env` file.
 
 
 # Running tests
@@ -185,7 +192,7 @@ poetry install --with dev
 
 Then, make sure to set up your mint's `.env` file to use a fake Lightning backend and disable Tor:
 ```bash
-MINT_LIGHTNING_BACKEND=FakeWallet
+MINT_BACKEND_BOLT11_SAT=FakeWallet
 TOR=FALSE
 ```
 You can run the tests with

cashu/core/settings.py

@@ -55,7 +55,11 @@ class MintSettings(CashuSettings):
     mint_derivation_path_list: List[str] = Field(default=[])
     mint_listen_host: str = Field(default="127.0.0.1")
     mint_listen_port: int = Field(default=3338)
-    mint_lightning_backend: str = Field(default="LNbitsWallet")
+
+    mint_lightning_backend: str = Field(default="")  # deprecated
+    mint_backend_bolt11_sat: str = Field(default="")
+    mint_backend_bolt11_usd: str = Field(default="")
+
     mint_database: str = Field(default="data/mint")
     mint_test_database: str = Field(default="test_data/test_mint")
     mint_peg_out_only: bool = Field(
@@ -204,5 +208,9 @@ def startup_settings_tasks():
     if settings.socks_host and settings.socks_port:
         settings.socks_proxy = f"socks5://{settings.socks_host}:{settings.socks_port}"
 
+    # backwards compatibility: set mint_backend_bolt11_sat from mint_lightning_backend
+    if settings.mint_lightning_backend:
+        settings.mint_backend_bolt11_sat = settings.mint_lightning_backend
+
 
 startup_settings_tasks()

cashu/lightning/__init__.py

@@ -7,5 +7,5 @@
 from .lndrest import LndRestWallet  # noqa: F401
 from .strike import StrikeUSDWallet  # noqa: F401
 
-if settings.mint_lightning_backend is None:
-    raise Exception("MINT_LIGHTNING_BACKEND not configured")
+if settings.mint_backend_bolt11_sat is None or settings.mint_backend_bolt11_usd is None:
+    raise Exception("MINT_BACKEND_BOLT11_SAT or MINT_BACKEND_BOLT11_USD not set")

cashu/lightning/base.py

@@ -62,12 +62,17 @@ def __str__(self) -> str:
 
 
 class LightningBackend(ABC):
-    units: set[Unit]
+    supported_units: set[Unit]
+    unit: Unit
 
     def assert_unit_supported(self, unit: Unit):
-        if unit not in self.units:
+        if unit not in self.supported_units:
             raise Unsupported(f"Unit {unit} is not supported")
 
+    @abstractmethod
+    def __init__(self, unit: Unit, **kwargs):
+        pass
+
     @abstractmethod
     def status(self) -> Coroutine[None, None, StatusResponse]:
         pass

cashu/lightning/blink.py

@@ -36,7 +36,6 @@ class BlinkWallet(LightningBackend):
     Create API Key at: https://dashboard.blink.sv/
     """
 
-    units = set([Unit.sat, Unit.usd])
     wallet_ids: Dict[Unit, str] = {}
     endpoint = "https://api.blink.sv/graphql"
     invoice_statuses = {"PENDING": None, "PAID": True, "EXPIRED": False}
@@ -47,7 +46,12 @@ class BlinkWallet(LightningBackend):
     }
     payment_statuses = {"SUCCESS": True, "PENDING": None, "FAILURE": False}
 
-    def __init__(self):
+    supported_units = set([Unit.sat, Unit.msat])
+    unit = Unit.sat
+
+    def __init__(self, unit: Unit = Unit.sat, **kwargs):
+        self.assert_unit_supported(unit)
+        self.unit = unit
         assert settings.mint_blink_key, "MINT_BLINK_KEY not set"
         self.client = httpx.AsyncClient(
             verify=not settings.debug,
@@ -297,7 +301,7 @@ async def get_payment_status(self, checking_id: str) -> PaymentStatus:
                                     ... on SettlementViaLn {
                                         preImage
                                     }
-                                } 
+                                }
                             }
                         }
                     }

cashu/lightning/corelightningrest.py

@@ -26,9 +26,12 @@
 
 
 class CoreLightningRestWallet(LightningBackend):
-    units = set([Unit.sat, Unit.msat])
+    supported_units = set([Unit.sat, Unit.msat])
+    unit = Unit.sat
 
-    def __init__(self):
+    def __init__(self, unit: Unit = Unit.sat, **kwargs):
+        self.assert_unit_supported(unit)
+        self.unit = unit
         macaroon = settings.mint_corelightning_rest_macaroon
         assert macaroon, "missing cln-rest macaroon"
 

cashu/lightning/fake.py

@@ -1,5 +1,6 @@
 import asyncio
 import hashlib
+import math
 import random
 from datetime import datetime
 from os import urandom
@@ -28,7 +29,7 @@
 
 
 class FakeWallet(LightningBackend):
-    units = set([Unit.sat, Unit.msat])
+    fake_btc_price = 1e8 / 1337
     queue: asyncio.Queue[Bolt11] = asyncio.Queue(0)
     payment_secrets: Dict[str, str] = dict()
     paid_invoices: Set[str] = set()
@@ -41,6 +42,13 @@ class FakeWallet(LightningBackend):
         32,
     ).hex()
 
+    supported_units = set([Unit.sat, Unit.msat, Unit.usd])
+    unit = Unit.sat
+
+    def __init__(self, unit: Unit = Unit.sat, **kwargs):
+        self.assert_unit_supported(unit)
+        self.unit = unit
+
     async def status(self) -> StatusResponse:
         return StatusResponse(error_message=None, balance=1337)
 
@@ -80,9 +88,19 @@ async def create_invoice(
 
         self.payment_secrets[payment_hash] = secret
 
+        amount_msat = 0
+        if self.unit == Unit.sat:
+            amount_msat = MilliSatoshi(amount.to(Unit.msat, round="up").amount)
+        elif self.unit == Unit.usd:
+            amount_msat = MilliSatoshi(
+                math.ceil(amount.amount / self.fake_btc_price * 1e9)
+            )
+        else:
+            raise NotImplementedError()
+
         bolt11 = Bolt11(
             currency="bc",
-            amount_msat=MilliSatoshi(amount.to(Unit.msat, round="up").amount),
+            amount_msat=amount_msat,
             date=int(datetime.now().timestamp()),
             tags=tags,
         )
@@ -137,10 +155,19 @@ async def paid_invoices_stream(self) -> AsyncGenerator[str, None]:
     async def get_payment_quote(self, bolt11: str) -> PaymentQuoteResponse:
         invoice_obj = decode(bolt11)
         assert invoice_obj.amount_msat, "invoice has no amount."
-        amount_msat = int(invoice_obj.amount_msat)
-        fees_msat = fee_reserve(amount_msat)
-        fees = Amount(unit=Unit.msat, amount=fees_msat)
-        amount = Amount(unit=Unit.msat, amount=amount_msat)
+
+        if self.unit == Unit.sat:
+            amount_msat = int(invoice_obj.amount_msat)
+            fees_msat = fee_reserve(amount_msat)
+            fees = Amount(unit=Unit.msat, amount=fees_msat)
+            amount = Amount(unit=Unit.msat, amount=amount_msat)
+        elif self.unit == Unit.usd:
+            amount_usd = math.ceil(invoice_obj.amount_msat / 1e9 * self.fake_btc_price)
+            amount = Amount(unit=Unit.usd, amount=amount_usd)
+            fees = Amount(unit=Unit.usd, amount=1)
+        else:
+            raise NotImplementedError()
+
         return PaymentQuoteResponse(
             checking_id=invoice_obj.payment_hash, fee=fees, amount=amount
         )

cashu/lightning/lnbits.py

@@ -22,9 +22,12 @@
 class LNbitsWallet(LightningBackend):
     """https://github.com/lnbits/lnbits"""
 
-    units = set([Unit.sat])
+    supported_units = set([Unit.sat])
+    unit = Unit.sat
 
-    def __init__(self):
+    def __init__(self, unit: Unit = Unit.sat, **kwargs):
+        self.assert_unit_supported(unit)
+        self.unit = unit
         self.endpoint = settings.mint_lnbits_endpoint
         self.client = httpx.AsyncClient(
             verify=not settings.debug,

cashu/lightning/lndrest.py

@@ -27,9 +27,12 @@
 class LndRestWallet(LightningBackend):
     """https://api.lightning.community/rest/index.html#lnd-rest-api-reference"""
 
-    units = set([Unit.sat, Unit.msat])
+    supported_units = set([Unit.sat, Unit.msat])
+    unit = Unit.sat
 
-    def __init__(self):
+    def __init__(self, unit: Unit = Unit.sat, **kwargs):
+        self.assert_unit_supported(unit)
+        self.unit = unit
         endpoint = settings.mint_lnd_rest_endpoint
         cert = settings.mint_lnd_rest_cert
 

cashu/lightning/strike.py

@@ -19,9 +19,11 @@
 class StrikeUSDWallet(LightningBackend):
     """https://github.com/lnbits/lnbits"""
 
-    units = [Unit.usd]
+    supported_units = [Unit.usd]
 
-    def __init__(self):
+    def __init__(self, unit: Unit = Unit.usd, **kwargs):
+        self.assert_unit_supported(unit)
+        self.unit = unit
         self.endpoint = "https://api.strike.me"
 
         # bearer auth with settings.mint_strike_key

cashu/mint/ledger.py

@@ -1,6 +1,5 @@
 import asyncio
 import copy
-import math
 import time
 from typing import Dict, List, Mapping, Optional, Tuple
 
@@ -493,10 +492,10 @@ async def melt_quote(
         if mint_quote:
             # internal transaction, validate and return amount from
             # associated mint quote and demand zero fees
-            assert (
-                Amount(unit, mint_quote.amount).to(Unit.msat).amount
-                == invoice_obj.amount_msat
-            ), "amounts do not match"
+            # assert (
+            #     Amount(unit, mint_quote.amount).to(Unit.msat).amount
+            #     == invoice_obj.amount_msat
+            # ), "amounts do not match"
             assert request == mint_quote.request, "bolt11 requests do not match"
             assert mint_quote.unit == melt_quote.unit, "units do not match"
             assert mint_quote.method == method.name, "methods do not match"
@@ -506,7 +505,7 @@ async def melt_quote(
             payment_quote = PaymentQuoteResponse(
                 checking_id=mint_quote.checking_id,
                 amount=Amount(unit, mint_quote.amount),
-                fee=Amount(unit=Unit.msat, amount=0),
+                fee=Amount(unit, amount=0),
             )
             logger.info(
                 f"Issuing internal melt quote: {request} ->"
@@ -622,11 +621,12 @@ async def melt_mint_settle_internally(self, melt_quote: MeltQuote) -> MeltQuote:
         bolt11_request = melt_quote.request
         invoice_obj = bolt11.decode(bolt11_request)
         assert invoice_obj.amount_msat, "invoice has no amount."
-        invoice_amount_sat = math.ceil(invoice_obj.amount_msat / 1000)
-        assert (
-            Amount(Unit[melt_quote.unit], mint_quote.amount).to(Unit.sat).amount
-            == invoice_amount_sat
-        ), "amounts do not match"
+        # invoice_amount_sat = math.ceil(invoice_obj.amount_msat / 1000)
+        # assert (
+        #     Amount(Unit[melt_quote.unit], mint_quote.amount).to(Unit.sat).amount
+        #     == invoice_amount_sat
+        # ), "amounts do not match"
+        assert mint_quote.amount == melt_quote.amount, "amounts do not match"
         assert bolt11_request == mint_quote.request, "bolt11 requests do not match"
         assert mint_quote.unit == melt_quote.unit, "units do not match"
         assert mint_quote.method == melt_quote.method, "methods do not match"

cashu/mint/startup.py

@@ -3,13 +3,15 @@
 
 import asyncio
 import importlib
+from typing import Dict
 
 from loguru import logger
 
 from ..core.base import Method, Unit
 from ..core.db import Database
 from ..core.migrations import migrate_databases
 from ..core.settings import settings
+from ..lightning.base import LightningBackend
 from ..mint import migrations
 from ..mint.crud import LedgerCrudSqlite
 from ..mint.ledger import Ledger
@@ -31,23 +33,24 @@
     logger.debug(f"{key}: {value}")
 
 wallets_module = importlib.import_module("cashu.lightning")
-lightning_backend = getattr(wallets_module, settings.mint_lightning_backend)()
 
-assert settings.mint_private_key is not None, "No mint private key set."
+backends: Dict[Method, Dict[Unit, LightningBackend]] = {}
+if settings.mint_backend_bolt11_sat:
+    backend_bolt11_sat = getattr(wallets_module, settings.mint_backend_bolt11_sat)(
+        unit=Unit.sat
+    )
+    backends.setdefault(Method.bolt11, {})[Unit.sat] = backend_bolt11_sat
+if settings.mint_backend_bolt11_usd:
+    backend_bolt11_usd = getattr(wallets_module, settings.mint_backend_bolt11_usd)(
+        unit=Unit.usd
+    )
+    backends.setdefault(Method.bolt11, {})[Unit.usd] = backend_bolt11_usd
+if not backends:
+    raise Exception("No backends are set.")
+
+if not settings.mint_private_key:
+    raise Exception("No mint private key is set.")
 
-# strike_backend = getattr(wallets_module, "StrikeUSDWallet")()
-# backends = {
-#     Method.bolt11: {Unit.sat: lightning_backend, Unit.usd: strike_backend},
-# }
-# backends = {
-#     Method.bolt11: {Unit.sat: lightning_backend, Unit.msat: lightning_backend},
-# }
-# backends = {
-#     Method.bolt11: {Unit.sat: lightning_backend, Unit.msat: lightning_backend,
-# }
-backends = {
-    Method.bolt11: {Unit.sat: lightning_backend},
-}
 ledger = Ledger(
     db=Database("mint", settings.mint_database),
     seed=settings.mint_private_key,