Merge remote-tracking branch 'origin/topic/timw/4742-skip-storage-thread'

* origin/topic/timw/4742-skip-storage-thread:
  Avoid starting up storage expiration thread with zero backends
  Remove a couple of obsolete TODOs in storage manager

CHANGES

@@ -1,3 +1,9 @@
+8.1.0-dev.555 | 2025-09-17 08:44:43 -0700
+
+  * Avoid starting up storage expiration thread with zero backends (Tim Wojtulewicz, Corelight)
+
+  * Remove a couple of obsolete TODOs in storage manager (Tim Wojtulewicz, Corelight)
+
 8.1.0-dev.552 | 2025-09-16 13:31:39 -0700
 
   * Reword comment about when ZeroMQ is required for the build (Tim Wojtulewicz, Corelight)

VERSION

@@ -1 +1 @@
-8.1.0-dev.552
+8.1.0-dev.555

src/storage/Manager.cc

@@ -22,7 +22,7 @@ void detail::ExpirationTimer::Dispatch(double t, bool is_expire) {
     // start another one running. If this causes us to skip a cycle, that's not
     // a big deal as the next cycle will catch anything that should be expired
     // in the interim.
-    if ( ! expire_running.test_and_set() ) {
+    if ( ! expire_running.test_and_set() && storage_mgr->BackendCount() > 0 ) {
         DBG_LOG(DBG_STORAGE, "Starting new expiration thread");
         storage_mgr->expiration_thread = zeek::jthread([t]() { storage_mgr->Expire(t); });
     }
@@ -100,8 +100,6 @@ OperationResult Manager::OpenBackend(BackendPtr backend, OpenResultCallback* cb,
 
     RegisterBackend(std::move(backend));
 
-    // TODO: post Storage::backend_opened event
-
     return res;
 }
 
@@ -116,11 +114,7 @@ OperationResult Manager::CloseBackend(BackendPtr backend, ResultCallback* cb) {
             backends.erase(it);
     }
 
-    auto res = backend->Close(cb);
-
-    // TODO: post Storage::backend_lost event
-
-    return res;
+    return backend->Close(cb);
 }
 
 void Manager::Expire(double t) {
@@ -152,4 +146,11 @@ void Manager::RegisterBackend(BackendPtr backend) {
     DBG_LOG(DBG_STORAGE, "Registered backends: %zu", backends.size());
 }
 
+size_t Manager::BackendCount() {
+    // Expiration runs on a separate thread and loops over the vector of backends. The mutex
+    // here ensures exclusive access.
+    std::unique_lock<std::mutex> lk(backends_mtx);
+    return backends.size();
+}
+
 } // namespace zeek::storage

src/storage/Manager.h

@@ -113,6 +113,7 @@ protected:
     friend class storage::detail::ExpirationTimer;
     void RunExpireThread();
     void StartExpirationTimer();
+    size_t BackendCount();
     zeek::jthread expiration_thread;
 
     friend class storage::OpenResultCallback;

testing/btest/scripts/base/frameworks/storage/redis-expiration.zeek

@@ -4,7 +4,7 @@
 # @TEST-PORT: REDIS_PORT
 
 # @TEST-EXEC: btest-bg-run redis-server run-redis-server ${REDIS_PORT%/tcp}
-# @TEST-EXEC: zcat <$TRACES/echo-connections.pcap.gz | zeek -B storage -b -r - %INPUT > out
+# @TEST-EXEC: zeek -B storage -b %INPUT > out
 # @TEST-EXEC: btest-bg-wait -k 1
 
 # @TEST-EXEC: btest-diff out