SERVER-45261 create more state in NiTL ctor

Calls to NetworkInterfaceTL::startCommand() before
NetworkInterfaceTL::startup() wil cause crashes (due to an assumption
inside NetworkInterfaceTL::startCommand() that we have a connection
pool.

That's out of contract for a NetworkInterface

To fix that, lets create more state on the NiTL in it's ctor, and only
spin up the background thread in startup().

4 files changed, 39 insertions, 18 deletions

diff --git a/src/mongo/executor/network_interface_integration_fixture.cpp b/src/mongo/executor/network_interface_integration_fixture.cpp
index ad2e31fdb03..62972eef6c3 100644
--- a/src/mongo/executor/network_interface_integration_fixture.cpp
+++ b/src/mongo/executor/network_interface_integration_fixture.cpp
@@ -47,7 +47,7 @@
 namespace mongo {
 namespace executor {
 
-void NetworkInterfaceIntegrationFixture::startNet(
+void NetworkInterfaceIntegrationFixture::createNet(
     std::unique_ptr<NetworkConnectionHook> connectHook) {
     ConnectionPool::Options options;
 #ifdef _WIN32
@@ -59,8 +59,13 @@ void NetworkInterfaceIntegrationFixture::startNet(
 #endif
     _net = makeNetworkInterface(
         "NetworkInterfaceIntegrationFixture", std::move(connectHook), nullptr, std::move(options));
+}
+
+void NetworkInterfaceIntegrationFixture::startNet(
+    std::unique_ptr<NetworkConnectionHook> connectHook) {
 
-    _net->startup();
+    createNet(std::move(connectHook));
+    net().startup();
 }
 
 void NetworkInterfaceIntegrationFixture::tearDown() {
diff --git a/src/mongo/executor/network_interface_integration_fixture.h b/src/mongo/executor/network_interface_integration_fixture.h
index 15c1a9f4361..eb164359d89 100644
--- a/src/mongo/executor/network_interface_integration_fixture.h
+++ b/src/mongo/executor/network_interface_integration_fixture.h
@@ -63,6 +63,7 @@ using StartCommandCB = std::function<void(const RemoteCommandResponse&)>;
 
 class NetworkInterfaceIntegrationFixture : public mongo::unittest::Test {
 public:
+    void createNet(std::unique_ptr<NetworkConnectionHook> connectHook = nullptr);
     void startNet(std::unique_ptr<NetworkConnectionHook> connectHook = nullptr);
     void tearDown() override;
 
diff --git a/src/mongo/executor/network_interface_integration_test.cpp b/src/mongo/executor/network_interface_integration_test.cpp
index 03cf7d2a1e9..8e593d0535b 100644
--- a/src/mongo/executor/network_interface_integration_test.cpp
+++ b/src/mongo/executor/network_interface_integration_test.cpp
@@ -73,6 +73,18 @@ TEST_F(NetworkInterfaceIntegrationFixture, Ping) {
     assertCommandOK("admin", BSON("ping" << 1));
 }
 
+TEST_F(NetworkInterfaceIntegrationFixture, PingWithoutStartup) {
+    createNet();
+
+    RemoteCommandRequest request{
+        fixture().getServers()[0], "admin", BSON("ping" << 1), BSONObj(), nullptr, Minutes(5)};
+
+    auto fut = runCommand(makeCallbackHandle(), request);
+    ASSERT_FALSE(fut.isReady());
+    net().startup();
+    ASSERT(fut.get().isOK());
+}
+
 // Hook that intentionally never finishes
 class HangingHook : public executor::NetworkConnectionHook {
     Status validateHost(const HostAndPort&,
diff --git a/src/mongo/executor/network_interface_tl.cpp b/src/mongo/executor/network_interface_tl.cpp
index e932130b005..01eceebbbd3 100644
--- a/src/mongo/executor/network_interface_tl.cpp
+++ b/src/mongo/executor/network_interface_tl.cpp
@@ -57,7 +57,25 @@ NetworkInterfaceTL::NetworkInterfaceTL(std::string instanceName,
       _connPoolOpts(std::move(connPoolOpts)),
       _onConnectHook(std::move(onConnectHook)),
       _metadataHook(std::move(metadataHook)),
-      _state(kDefault) {}
+      _state(kDefault) {
+    if (_svcCtx) {
+        _tl = _svcCtx->getTransportLayer();
+    }
+
+    // Even if you have a service context, it may not have a transport layer (mostly for unittests).
+    if (!_tl) {
+        warning() << "No TransportLayer configured during NetworkInterface startup";
+        _ownedTransportLayer =
+            transport::TransportLayerManager::makeAndStartDefaultEgressTransportLayer();
+        _tl = _ownedTransportLayer.get();
+    }
+
+    _reactor = _tl->getReactor(transport::TransportLayer::kNewReactor);
+    auto typeFactory = std::make_unique<connection_pool_tl::TLTypeFactory>(
+        _reactor, _tl, std::move(_onConnectHook), _connPoolOpts);
+    _pool = std::make_shared<ConnectionPool>(
+        std::move(typeFactory), std::string("NetworkInterfaceTL-") + _instanceName, _connPoolOpts);
+}
 
 std::string NetworkInterfaceTL::getDiagnosticString() {
     return "DEPRECATED: getDiagnosticString is deprecated in NetworkInterfaceTL";
@@ -84,22 +102,7 @@ std::string NetworkInterfaceTL::getHostName() {
 
 void NetworkInterfaceTL::startup() {
     stdx::lock_guard<Latch> lk(_mutex);
-    if (_svcCtx) {
-        _tl = _svcCtx->getTransportLayer();
-    }
-
-    if (!_tl) {
-        warning() << "No TransportLayer configured during NetworkInterface startup";
-        _ownedTransportLayer =
-            transport::TransportLayerManager::makeAndStartDefaultEgressTransportLayer();
-        _tl = _ownedTransportLayer.get();
-    }
 
-    _reactor = _tl->getReactor(transport::TransportLayer::kNewReactor);
-    auto typeFactory = std::make_unique<connection_pool_tl::TLTypeFactory>(
-        _reactor, _tl, std::move(_onConnectHook), _connPoolOpts);
-    _pool = std::make_shared<ConnectionPool>(
-        std::move(typeFactory), std::string("NetworkInterfaceTL-") + _instanceName, _connPoolOpts);
     _ioThread = stdx::thread([this] {
         setThreadName(_instanceName);
         _run();