feat: lnd client + rust binary to run btcd and lnd (#43)

.github/workflows/ci.yml

@@ -77,10 +77,21 @@ jobs:
 
       - name: Integration tests
         run: |-
-          mix phx.server &
-          CASHUBREW_SERVER_PID=$!
-          cd integration-tests && cargo test
-          kill $CASHUBREW_SERVER_PID
+          cd integration-tests
+          touch .env
+          cargo run &
+          BTCD_AND_LND_SERVERS_PID=$!
+          # Wait until the nodes are running by checking if the the env var are exported
+          while [[ -z "${LND_URL}" ]]; do sleep 1 && source .env; done
+          cd ..
+          # mix doesn't behave when run in background, so we use `erlang -detached` instead
+          # but the `$!` thing won't work coz the app is run in another thread,
+          # so we write the actual pid in a file and later read it to kill it 
+          elixir --erl "-detached" -e "File.write! 'pid', :os.getpid" -S mix phx.server
+          cd integration-tests
+          cargo test
+          cat ../pid | xargs kill
+          kill $BTCD_AND_LND_SERVERS_PID
 
           
 

config/dev.exs

@@ -42,3 +42,5 @@ config :cashubrew, Cashubrew.Repo,
 config :cashubrew, :repo, Cashubrew.Repo
 
 config :cashubrew, ecto_repos: [Cashubrew.Repo]
+
+config :cashubrew, :lnd_client, Cashubrew.LightingNetwork.Lnd

config/prod.exs

@@ -21,3 +21,5 @@ config :cashubrew, Cashubrew.Web.Endpoint, secret_key_base: System.get_env("SECR
 
 # Do not print debug messages in production
 config :logger, level: :info
+
+config :cashubrew, :lnd_client, Cashubrew.LightingNetwork.Lnd

config/runtime.exs

@@ -1,5 +1,7 @@
 import Config
 
+config :cashubrew, :lnd_client, Cashubrew.LightingNetwork.MockLnd
+
 if config_env() == :prod do
   database_url =
     System.get_env("DATABASE_URL") ||

config/test.exs

@@ -25,4 +25,6 @@ else
     pool_size: 10
 
   config :cashubrew, :repo, Cashubrew.Repo
+
+  config :cashubrew, :lnd_client, Cashubrew.LightingNetwork.MockLnd
 end

integration-tests/Cargo.toml

@@ -9,6 +9,11 @@ rand = "0.8.5"
 assert_matches = "1.5.0"
 tokio = "1.41.0"
 uuid = "1.11.0"
+anyhow = "1.0.91"
+bitcoind = { version = "0.34.2", features = ["26_0"] }
+lnd = { version = "0.1.6", features = ["lnd_0_17_5"] }
+tonic_lnd = "0.5.1"
+ctrlc = "3.4"
 
 [[test]]
 name = "nut06"

integration-tests/src/main.rs

@@ -0,0 +1,60 @@
+use bitcoind::bitcoincore_rpc::RpcApi;
+use lnd::Lnd;
+use lnd::LndConf;
+use std::sync::mpsc::channel;
+
+#[tokio::main]
+async fn main() {
+    println!("Downloading bitcoind...");
+    let bitcoind = bitcoind::BitcoinD::from_downloaded().unwrap();
+    assert_eq!(0, bitcoind.client.get_blockchain_info().unwrap().blocks);
+    println!("Done");
+    println!(
+        "bitcoind is running. Listening to {:?}",
+        bitcoind.params.rpc_socket
+    );
+
+    println!("Downloading lnd...");
+    let lnd_conf = LndConf::default();
+    let mut lnd = Lnd::with_conf(
+        lnd::exe_path().unwrap(),
+        &lnd_conf,
+        bitcoind
+            .params
+            .cookie_file
+            .clone()
+            .into_os_string()
+            .into_string()
+            .unwrap(),
+        bitcoind.params.rpc_socket.to_string(),
+        &bitcoind,
+    )
+    .await
+    .unwrap();
+    assert!(lnd
+        .client
+        .lightning()
+        .get_info(tonic_lnd::lnrpc::GetInfoRequest {})
+        .await
+        .is_ok());
+    println!("Done");
+    std::fs::write(
+        ".env",
+        format!(
+            "export LND_URL={:?}\nexport LND_CERT={:?}\nexport LND_MACAROON={:?}",
+            lnd.grpc_url,
+            lnd.tls_cert_path(),
+            lnd.admin_macaroon_path()
+        ),
+    )
+    .unwrap();
+
+    let (tx, rx) = channel();
+
+    ctrlc::set_handler(move || tx.send(()).expect("Could not send signal on channel."))
+        .expect("Error setting Ctrl-C handler");
+
+    println!("Press ctrl+c to exit");
+
+    rx.recv().expect("Could not receive from channel.");
+}

lib/cashubrew/NUTs/NUT-04/impl.ex

@@ -2,16 +2,16 @@ defmodule Cashubrew.Nuts.Nut04.Impl do
   @moduledoc """
   Implementation and structs of the NUT-04
   """
-  alias Cashubrew.Lightning.LightningNetworkService
   alias Cashubrew.Mint
   alias Cashubrew.Nuts.Nut00
   alias Cashubrew.Nuts.Nut04.Impl.MintQuoteMutex
   alias Cashubrew.Schema
 
-  def create_mint_quote!(amount, unit) do
+  def create_mint_quote!(amount, unit, description) do
     repo = Application.get_env(:cashubrew, :repo)
 
-    {payment_request, _payment_hash} = LightningNetworkService.create_invoice!(amount, unit)
+    {payment_request, _payment_hash} =
+      Cashubrew.LightingNetwork.Lnd.create_invoice!(amount, unit, description)
 
     # Note: quote is a unique and random id generated by the mint to internally look up the payment state.
     # quote MUST remain a secret between user and mint and MUST NOT be derivable from the payment request.

lib/cashubrew/application.ex

@@ -7,21 +7,13 @@ defmodule Cashubrew.Application do
   def start(_type, _args) do
     children = [
       Cashubrew.Web.Telemetry,
+      Application.get_env(:cashubrew, :lnd_client),
       {Phoenix.PubSub, name: Cashubrew.PubSub},
-      Endpoint
+      Endpoint,
+      Application.get_env(:cashubrew, :repo),
+      {Task, fn -> Cashubrew.Mint.init() end}
     ]
 
-    # Conditionally add the appropriate repo to the children list
-    children =
-      case Application.get_env(:cashubrew, :repo) do
-        Cashubrew.MockRepo -> [Cashubrew.MockRepo | children]
-        Cashubrew.Repo -> [Cashubrew.Repo | children]
-        _ -> children
-      end
-
-    # Always add Cashubrew.Mint after the repo
-    children = children ++ [{Task, fn -> Cashubrew.Mint.init() end}]
-
     opts = [strategy: :one_for_one, name: Cashubrew.Supervisor]
     Supervisor.start_link(children, opts)
   end

lib/cashubrew/lightning/lnd_client.ex

@@ -0,0 +1,72 @@
+defmodule Cashubrew.LightingNetwork.Lnd do
+  @moduledoc """
+    Client to interact with lnd
+  """
+  use GenServer
+  require Logger
+
+  def start_link(arg) do
+    GenServer.start_link(__MODULE__, arg, name: __MODULE__)
+  end
+
+  def init(args) do
+    node_url = URI.parse(System.get_env("LND_URL"))
+    creds = get_creds(System.get_env("LND_CERT"))
+    macaroon = get_macaroon(System.get_env("LND_MACAROON"))
+
+    Logger.debug("gRPC client connecting to gateway at #{node_url}")
+
+    case GRPC.Stub.connect("#{node_url.host}:#{node_url.port}",
+           cred: creds
+         ) do
+      {:error, error} ->
+        Logger.critical("Could not connect. Retrying... #{error}")
+        init(args)
+
+      {:ok, channel} ->
+        Logger.info("Connected to the gateway at #{node_url}")
+        {:ok, %{channel: channel, macaroon: macaroon}}
+    end
+  end
+
+  # one day
+  def validity, do: 86_400
+
+  def create_invoice!(amount, unit, description) do
+    GenServer.call(__MODULE__, {:create_invoice, amount, unit, description}, __MODULE__)
+  end
+
+  def handle_call({:create_invoice, amount, unit, description}, _from, state) do
+    if unit != "sat" do
+      raise "UnsuportedUnit"
+    end
+
+    amount_ms = amount * 1000
+
+    expiry = validity() + System.os_time(:second)
+
+    request = %Cashubrew.Lnrpc.Invoice{
+      memo: description,
+      value_msat: amount_ms,
+      expiry: expiry
+    }
+
+    {:ok, response} = Cashubrew.Lnrpc.Lightning.Stub.add_invoice(state["channel"], request)
+    {:reply, response, state}
+  end
+
+  defp get_creds(cert_path) do
+    filename = Path.expand(cert_path)
+
+    # ++ [verify: true/:verify_none]
+    ssl_opts = [cacertfile: filename]
+
+    GRPC.Credential.new(ssl: ssl_opts)
+  end
+
+  defp get_macaroon(macaroon_path) do
+    filename = Path.expand(macaroon_path)
+
+    File.read!(filename) |> Base.encode16()
+  end
+end