Making salt rotation interval configurable

Author: Mariusz Reichert

src/bin/electrs.rs

@@ -6,7 +6,7 @@ extern crate electrs;
 
 use crossbeam_channel::{self as channel};
 use error_chain::ChainedError;
-use std::{process, thread};
+use std::{env, process, thread};
 use std::sync::{Arc, RwLock};
 use std::time::Duration;
 use bitcoin::hex::DisplayHex;
@@ -29,6 +29,9 @@ use electrs::otlp_trace;
 use electrs::elements::AssetRegistry;
 use electrs::metrics::MetricOpts;
 
+/// Default salt rotation interval in seconds (24 hours)
+const DEFAULT_SALT_ROTATION_INTERVAL_SECS: u64 = 24 * 3600;
+
 fn fetch_from(config: &Config, store: &Store) -> FetchFrom {
     let mut jsonrpc_import = config.jsonrpc_import;
     if !jsonrpc_import {
@@ -166,13 +169,25 @@ fn rotate_salt(salt: &mut String) {
     *salt = generate_salt();
 }
 
+fn get_salt_rotation_interval() -> Duration {
+    let var_name = "SALT_ROTATION_INTERVAL_SECS";
+    let secs = env::var(var_name)
+        .ok()
+        .and_then(|val| val.parse::<u64>().ok())
+        .unwrap_or(DEFAULT_SALT_ROTATION_INTERVAL_SECS);
+
+    Duration::from_secs(secs)
+}
+
 fn spawn_salt_rotation_thread() -> Arc<RwLock<String>> {
     let salt = generate_salt();
     let salt_rwlock = Arc::new(RwLock::new(salt));
     let writer_arc = Arc::clone(&salt_rwlock);
+    let interval = get_salt_rotation_interval();
+
     thread::spawn(move || {
         loop {
-            thread::sleep(Duration::from_secs(24 * 3600)); // 24 hours
+            thread::sleep(interval); // 24 hours
             {
                 let mut guard = writer_arc.write().unwrap();
                 rotate_salt(&mut *guard);