From 99e23b48807515dade142c6bbbeb327847c155f4 Mon Sep 17 00:00:00 2001
From: Andrew Gouin <andrew@gouin.io>
Date: Thu, 16 Nov 2023 13:23:30 -0700
Subject: [PATCH] make local cosigner nonce cache expiration twice the leader
 nonce cache

---
 signer/cosigner_nonce_cache.go | 3 ++-
 signer/local_cosigner.go       | 4 +++-
 2 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/signer/cosigner_nonce_cache.go b/signer/cosigner_nonce_cache.go
index 6184e26b..eac24d92 100644
--- a/signer/cosigner_nonce_cache.go
+++ b/signer/cosigner_nonce_cache.go
@@ -14,6 +14,7 @@ const (
 	defaultGetNoncesInterval = 3 * time.Second
 	defaultGetNoncesTimeout  = 4 * time.Second
 	cachePreSize             = 10000
+	nonceCacheExpiration     = 10 * time.Second // half of the local cosigner cache expiration
 )
 
 type CosignerNonceCache struct {
@@ -201,7 +202,7 @@ func (cnc *CosignerNonceCache) LoadN(ctx context.Context, n int) {
 	var wg sync.WaitGroup
 	wg.Add(len(cnc.cosigners))
 
-	expiration := time.Now().Add(nonceExpiration)
+	expiration := time.Now().Add(nonceCacheExpiration)
 
 	for i, p := range cnc.cosigners {
 		i := i
diff --git a/signer/local_cosigner.go b/signer/local_cosigner.go
index 38404a30..5251b3f7 100644
--- a/signer/local_cosigner.go
+++ b/signer/local_cosigner.go
@@ -16,7 +16,9 @@ import (
 
 var _ Cosigner = &LocalCosigner{}
 
-const nonceExpiration = 10 * time.Second
+// double the CosignerNonceCache expiration so that sign requests from the leader
+// never reference nonces which have expired here in the LocalCosigner.
+const nonceExpiration = 20 * time.Second
 
 // LocalCosigner responds to sign requests.
 // It maintains a high watermark to avoid double-signing.