Merge pull request stratum-mining#214 from plebhash/2026-01-25-patch-broadcast-shutdown

add `SHUTDOWN_BROADCAST_CAPACITY` constant

Author: plebhash

miner-apps/jd-client/src/lib/mod.rs

@@ -8,6 +8,7 @@ use stratum_apps::{
     task_manager::TaskManager,
     tp_type::TemplateProviderType,
     utils::types::Sv2Frame,
+    SHUTDOWN_BROADCAST_CAPACITY,
 };
 use tokio::sync::{broadcast, mpsc};
 use tracing::{debug, error, info, warn};
@@ -51,7 +52,8 @@ pub struct JobDeclaratorClient {
 impl JobDeclaratorClient {
     /// Creates a new [`JobDeclaratorClient`] instance.
     pub fn new(config: JobDeclaratorClientConfig) -> Self {
-        let (notify_shutdown, _) = tokio::sync::broadcast::channel::<ShutdownMessage>(100);
+        let (notify_shutdown, _) =
+            tokio::sync::broadcast::channel::<ShutdownMessage>(SHUTDOWN_BROADCAST_CAPACITY);
         Self {
             config,
             notify_shutdown,

miner-apps/translator/src/lib/mod.rs

@@ -13,7 +13,9 @@
 #![allow(clippy::module_inception)]
 use async_channel::{unbounded, Receiver, Sender};
 use std::{net::SocketAddr, sync::Arc, time::Duration};
-use stratum_apps::{task_manager::TaskManager, utils::types::Sv2Frame};
+use stratum_apps::{
+    task_manager::TaskManager, utils::types::Sv2Frame, SHUTDOWN_BROADCAST_CAPACITY,
+};
 use tokio::sync::{broadcast, mpsc};
 use tracing::{debug, error, info, warn};
 
@@ -62,7 +64,8 @@ impl TranslatorSv2 {
     pub async fn start(self) {
         info!("Starting Translator Proxy...");
 
-        let (notify_shutdown, _) = broadcast::channel::<ShutdownMessage>(1);
+        let (notify_shutdown, _) =
+            broadcast::channel::<ShutdownMessage>(SHUTDOWN_BROADCAST_CAPACITY);
         let (shutdown_complete_tx, mut shutdown_complete_rx) = mpsc::channel::<()>(1);
         let task_manager = Arc::new(TaskManager::new());
         let (status_sender, status_receiver) = async_channel::unbounded::<Status>();

pool-apps/pool/src/lib/mod.rs

@@ -5,7 +5,7 @@ use async_channel::unbounded;
 use bitcoin_core_sv2::CancellationToken;
 use stratum_apps::{
     stratum_core::bitcoin::consensus::Encodable, task_manager::TaskManager,
-    tp_type::TemplateProviderType,
+    tp_type::TemplateProviderType, SHUTDOWN_BROADCAST_CAPACITY,
 };
 use tokio::sync::broadcast;
 use tracing::{debug, error, info, warn};
@@ -41,7 +41,8 @@ pub struct PoolSv2 {
 #[cfg_attr(not(test), hotpath::measure_all)]
 impl PoolSv2 {
     pub fn new(config: PoolConfig) -> Self {
-        let (notify_shutdown, _) = tokio::sync::broadcast::channel::<ShutdownMessage>(100);
+        let (notify_shutdown, _) =
+            tokio::sync::broadcast::channel::<ShutdownMessage>(SHUTDOWN_BROADCAST_CAPACITY);
         Self {
             config,
             notify_shutdown,

stratum-apps/src/lib.rs

@@ -75,3 +75,15 @@ pub mod tp_type;
 
 /// Creates a CoinbaseOutputConstraints message from a list of coinbase outputs
 pub mod coinbase_output_constraints;
+
+/// Maximum theoretical TCP client connections
+/// (limited by the number of file descriptors a process can have)
+const MAX_TCP_CLIENTS: usize = 1_048_576;
+
+/// Safety margin multiplier for shutdown broadcast buffer to handle stacked lags.
+const SHUTDOWN_BUFFER_SAFETY_MARGIN: usize = 4;
+
+/// Buffer size for shutdown broadcast channels.
+/// Calculated as MAX_TCP_CLIENTS × SHUTDOWN_BUFFER_SAFETY_MARGIN.
+/// TODO: migrate away from broadcast channels, see issue https://github.com/stratum-mining/sv2-apps/issues/215
+pub const SHUTDOWN_BROADCAST_CAPACITY: usize = MAX_TCP_CLIENTS * SHUTDOWN_BUFFER_SAFETY_MARGIN;