f - Parameterize maximum payment retry attempts

Author: jkczyz

lightning-invoice/src/payment.rs

@@ -48,10 +48,6 @@ use std::collections::hash_map::{self, HashMap};
 use std::ops::Deref;
 use std::sync::Mutex;
 
-/// The maximum number of payment attempts before forwarding the [`Event::PaymentFailed`] to be
-/// handled.
-const MAX_PAYMENT_ATTEMPTS: usize = 3;
-
 /// A utility for paying [`Invoice]`s.
 pub struct InvoicePayer<P: Deref, R, L: Deref, E>
 where
@@ -67,6 +63,7 @@ where
 	// Lock order: payment_attempts -> invoice_cache
 	invoice_cache: Mutex<HashMap<PaymentHash, Invoice>>,
 	payment_attempts: Mutex<HashMap<PaymentHash, usize>>,
+	retry_attempts: usize,
 }
 
 /// A trait defining behavior of an [`Invoice`] payer.
@@ -126,9 +123,16 @@ where
 			event_handler,
 			invoice_cache: Mutex::new(HashMap::new()),
 			payment_attempts: Mutex::new(HashMap::new()),
+			retry_attempts: 0,
 		}
 	}
 
+	/// Sets the maximum number of payment retry attempts before forwarding the
+	/// [`Event::PaymentFailed`] event to be handled by the decorated [`EventHandler`].
+	pub fn with_retry_attempts(self, retry_attempts: usize) -> Self {
+		Self { retry_attempts, ..self }
+	}
+
 	/// Pays the given [`Invoice`], caching it for later use if a retry is needed.
 	pub fn pay_invoice(&self, invoice: &Invoice) -> Result<(), PaymentError> {
 		let payment_hash = PaymentHash(invoice.payment_hash().clone().into_inner());
@@ -201,7 +205,8 @@ where
 					.and_modify(|attempts| *attempts += 1)
 					.or_insert(1);
 				if !rejected_by_dest {
-					if *attempts < MAX_PAYMENT_ATTEMPTS {
+					let max_payment_attempts = self.retry_attempts + 1;
+					if *attempts < max_payment_attempts {
 						if self.pay_cached_invoice(payment_hash).is_ok() {
 							log_trace!(self.logger, "Payment {} failed; retrying (attempts: {})", log_bytes!(payment_hash.0), attempts);
 							return;
@@ -293,7 +298,8 @@ mod tests {
 		let payer = TestPayer::new();
 		let router = NullRouter {};
 		let logger = TestLogger::new();
-		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler);
+		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler)
+			.with_retry_attempts(2);
 
 		let payment_preimage = PaymentPreimage([1; 32]);
 		let invoice = invoice(payment_preimage);
@@ -322,7 +328,8 @@ mod tests {
 		let payer = TestPayer::new();
 		let router = NullRouter {};
 		let logger = TestLogger::new();
-		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler);
+		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler)
+			.with_retry_attempts(2);
 
 		let payment_preimage = PaymentPreimage([1; 32]);
 		let invoice = invoice(payment_preimage);
@@ -355,7 +362,8 @@ mod tests {
 		let payer = TestPayer::new().fails_on_attempt(2);
 		let router = NullRouter {};
 		let logger = TestLogger::new();
-		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler);
+		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler)
+			.with_retry_attempts(2);
 
 		let payment_preimage = PaymentPreimage([1; 32]);
 		let invoice = invoice(payment_preimage);
@@ -380,7 +388,8 @@ mod tests {
 		let payer = TestPayer::new();
 		let router = NullRouter {};
 		let logger = TestLogger::new();
-		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler);
+		let invoice_payer = InvoicePayer::new(&payer, router, &logger, event_handler)
+			.with_retry_attempts(2);
 
 		let payment_preimage = PaymentPreimage([1; 32]);
 		let invoice = invoice(payment_preimage);