Sanity checking libevent is initialized

source/common/event/dispatcher_impl.cc

@@ -26,13 +26,18 @@ namespace Envoy {
 namespace Event {
 
 DispatcherImpl::DispatcherImpl()
-    : DispatcherImpl(Buffer::WatermarkFactoryPtr{new Buffer::WatermarkBufferFactory}) {}
+    : DispatcherImpl(Buffer::WatermarkFactoryPtr{new Buffer::WatermarkBufferFactory}) {
+  // The dispatcher won't work as expected if libevent hasn't been configured to use threads.
+  RELEASE_ASSERT(Libevent::Global::initialized());
+}
 
 DispatcherImpl::DispatcherImpl(Buffer::WatermarkFactoryPtr&& factory)
     : buffer_factory_(std::move(factory)), base_(event_base_new()),
       deferred_delete_timer_(createTimer([this]() -> void { clearDeferredDeleteList(); })),
       post_timer_(createTimer([this]() -> void { runPostCallbacks(); })),
-      current_to_delete_(&to_delete_1_) {}
+      current_to_delete_(&to_delete_1_) {
+  RELEASE_ASSERT(Libevent::Global::initialized());
+}
 
 DispatcherImpl::~DispatcherImpl() {}
 

source/common/event/libevent.cc

@@ -10,11 +10,14 @@ namespace Envoy {
 namespace Event {
 namespace Libevent {
 
+bool Global::initialized_ = false;
+
 void Global::initialize() {
   evthread_use_pthreads();
 
   // Ignore SIGPIPE and allow errors to propagate through error codes.
   signal(SIGPIPE, SIG_IGN);
+  initialized_ = true;
 }
 
 } // namespace Libevent

source/common/event/libevent.h

@@ -31,10 +31,16 @@ namespace Libevent {
  */
 class Global {
 public:
+  static bool initialized() { return initialized_; }
+
   /**
    * Initialize the library globally.
    */
   static void initialize();
+
+private:
+  // True if initialized() has been called.
+  static bool initialized_;
 };
 
 typedef CSmartPtr<event_base, event_base_free> BasePtr;

test/integration/integration.cc

@@ -15,6 +15,7 @@
 #include "common/buffer/buffer_impl.h"
 #include "common/common/assert.h"
 #include "common/event/dispatcher_impl.h"
+#include "common/event/libevent.h"
 #include "common/network/connection_impl.h"
 #include "common/network/utility.h"
 #include "common/upstream/upstream_impl.h"
@@ -199,6 +200,7 @@ Network::ClientConnectionPtr BaseIntegrationTest::makeClientConnection(uint32_t
 
 void BaseIntegrationTest::initialize() {
   RELEASE_ASSERT(!initialized_);
+  RELEASE_ASSERT(Event::Libevent::Global::initialized());
   initialized_ = true;
 
   createUpstreams();