fix: do not block identify on SSE client shutdown completion

Author: cwaldren-ld

libs/client-sdk/src/client_impl.cpp

@@ -149,14 +149,11 @@ std::future<bool> ClientImpl::IdentifyAsync(Context context) {
 }
 
 void ClientImpl::RestartDataSource() {
-    auto start_op = [this]() {
-        data_source_ = data_source_factory_();
-        data_source_->Start();
-    };
-    if (!data_source_) {
-        return start_op();
+    if (data_source_) {
+        data_source_->ShutdownAsync(nullptr);
     }
-    data_source_->ShutdownAsync(start_op);
+    data_source_ = data_source_factory_();
+    data_source_->Start();
 }
 
 std::future<bool> ClientImpl::StartAsyncInternal(
@@ -170,7 +167,7 @@ std::future<bool> ClientImpl::StartAsyncInternal(
             if (auto const state = status.State(); IsInitialized(state)) {
                 init_promise->set_value(result(status.State()));
                 return true; /* delete this change listener since the desired
-                                state was reached */
+                        state was reached */
             }
             return false; /* keep the change listener */
         });

libs/server-sent-events/src/client.cpp

@@ -44,6 +44,13 @@ auto const kDefaultInitialReconnectDelay = std::chrono::seconds(1);
 // Maximum duration between backoff attempts.
 auto const kDefaultMaxBackoffDelay = std::chrono::seconds(30);
 
+// When we shut down the SSL stream using async_shutdown operation, it
+// appears that the completion handler isn't invoked for about 5 minutes. Either
+// we or the server are misbehaving here. In any case, there is no need to wait
+// 5 minutes, we should give a couple seconds to receive a valid response or
+// else stop waiting.
+auto const kShutdownTimeout = std::chrono::seconds(5);
+
 static boost::optional<net::ssl::context&> ToOptRef(
     std::optional<net::ssl::context>& maybe_val) {
     if (maybe_val) {
@@ -341,15 +348,17 @@ class FoxyClient : public Client,
     void do_shutdown(std::function<void()> completion) {
         shutting_down_ = true;
         backoff_timer_.cancel();
+        session_->opts.timeout = kShutdownTimeout;
+        if (session_->stream.is_ssl()) {
+            session_->stream.ssl().next_layer().cancel();
+        }
         session_->async_shutdown(beast::bind_front_handler(
-            &FoxyClient::on_shutdown, std::move(completion)));
+            &FoxyClient::on_shutdown, shared_from_this(),
+            std::move(completion)));
     }
 
-    static void on_shutdown(std::function<void()> completion,
-                            boost::system::error_code ec) {
-        // Because do_shutdown doesn't use shared_from_this() when initiating
-        // the async_shutdown op, the client may already be destroyed - hence
-        // this static method.
+    void on_shutdown(std::function<void()> completion,
+                     boost::system::error_code ec) {
         boost::ignore_unused(ec);
         if (completion) {
             completion();