coordinator: get_spend_transaction

Cargo.toml

@@ -5,6 +5,7 @@ authors = ["Antoine Poinsot <[email protected]>"]
 edition = "2018"
 
 [dependencies]
+bitcoinconsensus = "0.19.0-2"
 revault_tx = { version = "0.5", features = ["use-serde"] }
 revault_net = "0.3"
 

doc/PLUGIN.md

@@ -32,11 +32,12 @@ An overview of the spending attempts at the current block.
 
 ##### Vault resource 
 
-| Field              | Type    | Description                                  |
-| ------------------ | ------- | -------------------------------------------- |
-| `value`            | integer | Value of the vault in satoshis               |
-| `deposit_outpoint` | string  | Deposit outpoint of the vault                |
-| `unvault_tx`       | string  | Psbt of the unvault transaction of the vault |
+| Field              | Type           | Description                                                                                             |
+| ------------------ | -------------- | --------------------------------------------                                                            |
+| `value`            | integer        | Value of the vault in satoshis                                                                          |
+| `deposit_outpoint` | string         | Deposit outpoint of the vault                                                                           |
+| `unvault_tx`       | string         | Psbt of the unvault transaction of the vault                                                            |
+| `candidate_tx`     | string or null | Hex encoded transaction spending the vault, null if the watchtower did not retrieve it from coordinator |
 
 #### Plugin Response
 

src/config.rs

@@ -127,6 +127,17 @@ pub struct BitcoindConfig {
     pub poll_interval_secs: Duration,
 }
 
+/// Everything we need to know for talking to coordinator
+#[derive(Debug, Clone, Deserialize)]
+pub struct CoordinatorConfig {
+    /// The Noise static public key of the sync server
+    #[serde(deserialize_with = "deserialize_noisepubkey")]
+    pub noise_key: NoisePubkey,
+    /// The host of the sync server (may be an IP or a hidden service)
+    /// TODO: change for enum handling multiple choice.
+    pub host: SocketAddr,
+}
+
 #[derive(Debug, Clone, Deserialize)]
 pub struct ScriptsConfig {
     #[serde(deserialize_with = "deserialize_fromstr")]
@@ -149,11 +160,8 @@ pub struct Config {
     /// The Noise static public keys of "our" stakeholder
     #[serde(deserialize_with = "deserialize_noisepubkey")]
     pub stakeholder_noise_key: NoisePubkey,
-    /// The host of the sync server (may be an IP or a hidden service)
-    pub coordinator_host: String,
-    /// The Noise static public key of the sync server
-    #[serde(deserialize_with = "deserialize_noisepubkey")]
-    pub coordinator_noise_key: NoisePubkey,
+    /// Everything we need to know to talk to coordinator
+    pub coordinator_config: Option<CoordinatorConfig>,
     /// An optional custom data directory
     // TODO: have a default implem as in cosignerd
     pub data_dir: Option<PathBuf>,
@@ -352,8 +360,9 @@ mod tests {
 
             stakeholder_noise_key = "3de4539519b6baca35ad14cd5bac9a4e0875a851632112405bb0547e6fcf16f6"
 
-            coordinator_host = "127.0.0.1:1"
-            coordinator_noise_key = "d91563973102454a7830137e92d0548bc83b4ea2799f1df04622ca1307381402"
+            [coordinator_config]
+            host = "127.0.0.1:1"
+            noise_key = "d91563973102454a7830137e92d0548bc83b4ea2799f1df04622ca1307381402"
 
             [scripts_config]
             cpfp_descriptor = "wsh(thresh(1,pk(xpub6BaZSKgpaVvibu2k78QsqeDWXp92xLHZxiu1WoqLB9hKhsBf3miBUDX7PJLgSPvkj66ThVHTqdnbXpeu8crXFmDUd4HeM4s4miQS2xsv3Qb/*)))#cwycq5xu"
@@ -384,8 +393,9 @@ mod tests {
 
             stakeholder_noise_key = "3de4539519b6baca35ad14cd5bac9a4e0875a851632112405bb0547e6fcf16f6"
 
-            coordinator_host = "127.0.0.1:1"
-            coordinator_noise_key = "d91563973102454a7830137e92d0548bc83b4ea2799f1df04622ca1307381402"
+            [coordinator_config]
+            host = "127.0.0.1:1"
+            noise_key = "d91563973102454a7830137e92d0548bc83b4ea2799f1df04622ca1307381402"
 
             [[plugins]]
             path = "src/config.rs"
@@ -416,8 +426,9 @@ mod tests {
 
             stakeholder_noise_key = "3de4539519b6baca35ad14cd5bac9a4e0875a851632112405bb0547e6fcf16f6"
 
-            coordinator_host = "127.0.0.1:1"
-            coordinator_noise_key = "d91563973102454a7830137e92d0548bc83b4ea2799f1df04622ca1307381402"
+            [coordinator_config]
+            host = "127.0.0.1:1"
+            noise_key = "d91563973102454a7830137e92d0548bc83b4ea2799f1df04622ca1307381402"
 
             [scripts_config]
             cpfp_descriptor = "wsh(thresh(1,pk(xpub6BaZSKgpaVvibu2k78QsqeDWXp92xLHZxiu1WoqLB9hKhsBf3miBUDX7PJLgSPvkj66ThVHTqdnbXpeu8crXFmDUd4HeM4s4miQS2xsv3Qb/*)))#cwycq5xu"

src/coordinator.rs

@@ -0,0 +1,83 @@
+use std::net::SocketAddr;
+
+use revault_net::{
+    message::coordinator::{GetSpendTx, SpendTx},
+    noise::{PublicKey, SecretKey},
+    transport::KKTransport,
+};
+
+use revault_tx::bitcoin::{OutPoint, Transaction};
+
+const COORDINATOR_CLIENT_RETRIES: usize = 3;
+
+pub struct CoordinatorClient {
+    host: SocketAddr,
+    our_noise_secret_key: SecretKey,
+    pub_key: PublicKey,
+    /// How many times the client will try again
+    /// to send a request to coordinator upon failure
+    retries: usize,
+}
+
+impl CoordinatorClient {
+    pub fn new(our_noise_secret_key: SecretKey, host: SocketAddr, pub_key: PublicKey) -> Self {
+        Self {
+            host,
+            our_noise_secret_key,
+            pub_key,
+            retries: COORDINATOR_CLIENT_RETRIES,
+        }
+    }
+
+    /// Wrapper to retry a request sent to coordinator upon IO failure
+    /// according to the configured number of retries.
+    fn retry<T, R: Fn() -> Result<T, revault_net::Error>>(
+        &self,
+        request: R,
+    ) -> Result<T, revault_net::Error> {
+        let mut error: Option<revault_net::Error> = None;
+        for _ in 0..self.retries {
+            match request() {
+                Ok(res) => return Ok(res),
+                Err(e) => error = Some(e),
+            }
+            log::debug!(
+                "Error while communicating with coordinator: {}, retrying",
+                error.as_ref().expect("An error must have happened"),
+            );
+            std::thread::sleep(std::time::Duration::from_secs(3));
+        }
+        Err(error.expect("An error must have happened"))
+    }
+
+    fn send_req<T>(&self, req: &revault_net::message::Request) -> Result<T, revault_net::Error>
+    where
+        T: serde::de::DeserializeOwned,
+    {
+        log::debug!(
+            "Sending request to Coordinator: '{}'",
+            serde_json::to_string(req).unwrap(),
+        );
+        let mut transport =
+            KKTransport::connect(self.host, &self.our_noise_secret_key, &self.pub_key)?;
+        transport.send_req(&req)
+    }
+
+    /// Get Spend transaction spending the vault with the given deposit outpoint.
+    /// Beware that the spend transaction may be invalid and needs to be verified against
+    /// libbitcoinconsensus.
+    pub fn get_spend_transaction(
+        &self,
+        deposit_outpoint: OutPoint,
+    ) -> Result<Option<Transaction>, revault_net::Error> {
+        let resp: SpendTx = self.retry(|| {
+            let msg = GetSpendTx { deposit_outpoint };
+            self.send_req(&msg.into())
+        })?;
+        log::debug!(
+            "Got from Coordinator: '{}'",
+            serde_json::to_string(&resp).unwrap()
+        );
+        Ok(resp.spend_tx)
+    }
+}

src/main.rs

@@ -1,5 +1,6 @@
 mod bitcoind;
 mod config;
+mod coordinator;
 mod daemonize;
 mod database;
 mod keys;
@@ -235,6 +236,7 @@ fn main() {
         let _db_path = db_path.clone();
         let _config = config.clone();
         let _bitcoind = bitcoind.clone();
+        let noise_secret = noise_secret.clone();
         move || {
             listener_main(&_db_path, &_config, _bitcoind, &noise_secret).unwrap_or_else(|e| {
                 log::error!("Error in listener loop: '{}'", e);
@@ -246,7 +248,7 @@ fn main() {
     log::info!("Started miradord.",);
 
     let secp_ctx = secp256k1::Secp256k1::verification_only();
-    poller::main_loop(&db_path, &secp_ctx, &config, &bitcoind).unwrap_or_else(|e| {
+    poller::main_loop(&db_path, &secp_ctx, &config, &bitcoind, noise_secret).unwrap_or_else(|e| {
         log::error!("Error in main loop: '{}'", e);
         process::exit(1);
     });

src/plugins.rs

@@ -1,5 +1,5 @@
 use revault_tx::{
-    bitcoin::{Amount, OutPoint},
+    bitcoin::{consensus::encode, Amount, OutPoint, Transaction},
     transactions::UnvaultTransaction,
 };
 
@@ -63,6 +63,12 @@ fn serialize_amount<S: Serializer>(amount: &Amount, serializer: S) -> Result<S::
     amount.as_sat().serialize(serializer)
 }
 
+fn serialize_tx<S: Serializer>(tx: &Option<Transaction>, serializer: S) -> Result<S::Ok, S::Error> {
+    tx.as_ref()
+        .map(|tx| encode::serialize_hex(tx))
+        .serialize(serializer)
+}
+
 #[derive(Debug, Clone, Eq, PartialEq)]
 pub struct Plugin {
     path: path::PathBuf,
@@ -76,7 +82,8 @@ pub struct VaultInfo {
     pub value: Amount,
     pub deposit_outpoint: OutPoint,
     pub unvault_tx: UnvaultTransaction,
-    // TODO: Spend tx
+    #[serde(serialize_with = "serialize_tx")]
+    pub candidate_tx: Option<Transaction>,
 }
 
 /// Information we are passing to a plugin after a new block if there was any update.
@@ -204,6 +211,7 @@ mod tests {
                 value: Amount::from_sat(567890),
                 deposit_outpoint,
                 unvault_tx: unvault_tx.clone(),
+                candidate_tx: None,
             })
             .collect();
         let many_outpoints: Vec<OutPoint> = (0..10000).map(|_| deposit_outpoint).collect();
@@ -239,6 +247,7 @@ mod tests {
             )
             .unwrap(),
             unvault_tx: unvault_tx.clone(),
+            candidate_tx: None,
         };
         let new_block = NewBlockInfo {
             new_attempts: vec![vault_info],
@@ -263,6 +272,7 @@ mod tests {
             value: Amount::from_sat(567890),
             deposit_outpoint,
             unvault_tx: unvault_tx.clone(),
+            candidate_tx: None,
         };
         let new_block = NewBlockInfo {
             new_attempts: vec![vault_info],