SERVER-27855 Attach all NetworkInterface instances with EgressHooks

with the exception of:
- NetworkInterfaceCollectionRangeDeleter-TaskExecutor (doesn't really use network)
- AddShard-TaskExecutor (destination shard is still not part of cluster)

4 files changed, 15 insertions, 6 deletions

diff --git a/src/mongo/s/client/shard_registry.cpp b/src/mongo/s/client/shard_registry.cpp
index 2b46213ec6b..5f30b22c8ea 100644
--- a/src/mongo/s/client/shard_registry.cpp
+++ b/src/mongo/s/client/shard_registry.cpp
@@ -41,11 +41,13 @@
 #include "mongo/db/client.h"
 #include "mongo/db/operation_context.h"
 #include "mongo/db/server_options.h"
+#include "mongo/executor/network_connection_hook.h"
 #include "mongo/executor/network_interface_factory.h"
 #include "mongo/executor/network_interface_thread_pool.h"
 #include "mongo/executor/task_executor.h"
 #include "mongo/executor/task_executor_pool.h"
 #include "mongo/executor/thread_pool_task_executor.h"
+#include "mongo/rpc/metadata/egress_metadata_hook_list.h"
 #include "mongo/s/catalog/sharding_catalog_client.h"
 #include "mongo/s/catalog/type_shard.h"
 #include "mongo/s/client/shard.h"
@@ -190,8 +192,11 @@ void ShardRegistry::startup() {
     // startup() must be called only once
     invariant(!_executor);
 
+    auto hookList = stdx::make_unique<rpc::EgressMetadataHookList>();
+    // TODO SERVER-27750: add LogicalTimeMetadataHook
+
     // construct task executor
-    auto net = executor::makeNetworkInterface("ShardRegistryUpdater");
+    auto net = executor::makeNetworkInterface("ShardRegistryUpdater", nullptr, std::move(hookList));
     auto netPtr = net.get();
     _executor = stdx::make_unique<ThreadPoolTaskExecutor>(
         stdx::make_unique<NetworkInterfaceThreadPool>(netPtr), std::move(net));
diff --git a/src/mongo/s/server.cpp b/src/mongo/s/server.cpp
index 1a5d0b28ea9..3fd4d4fb3dc 100644
--- a/src/mongo/s/server.cpp
+++ b/src/mongo/s/server.cpp
@@ -63,6 +63,7 @@
 #include "mongo/db/wire_version.h"
 #include "mongo/executor/task_executor_pool.h"
 #include "mongo/platform/process_id.h"
+#include "mongo/rpc/metadata/egress_metadata_hook_list.h"
 #include "mongo/s/balancer_configuration.h"
 #include "mongo/s/catalog/sharding_catalog_client.h"
 #include "mongo/s/catalog/sharding_catalog_manager.h"
@@ -201,7 +202,12 @@ static Status initializeSharding(OperationContext* txn) {
         mongosGlobalParams.configdbs,
         generateDistLockProcessId(txn),
         std::move(shardFactory),
-        []() { return stdx::make_unique<rpc::ShardingEgressMetadataHookForMongos>(); },
+        []() {
+            auto hookList = stdx::make_unique<rpc::EgressMetadataHookList>();
+            // TODO SERVER-27750: add LogicalTimeMetadataHook
+            hookList->addHook(stdx::make_unique<rpc::ShardingEgressMetadataHookForMongos>());
+            return hookList;
+        },
         [](ShardingCatalogClient* catalogClient, std::unique_ptr<executor::TaskExecutor> executor) {
             return nullptr;  // Only config servers get a real ShardingCatalogManager.
         });
diff --git a/src/mongo/s/sharding_initialization.cpp b/src/mongo/s/sharding_initialization.cpp
index a98d9b0941f..a4e3108eba4 100644
--- a/src/mongo/s/sharding_initialization.cpp
+++ b/src/mongo/s/sharding_initialization.cpp
@@ -60,7 +60,6 @@
 #include "mongo/s/cluster_identity_loader.h"
 #include "mongo/s/grid.h"
 #include "mongo/s/query/cluster_cursor_manager.h"
-#include "mongo/s/sharding_egress_metadata_hook.h"
 #include "mongo/stdx/memory.h"
 #include "mongo/util/exit.h"
 #include "mongo/util/log.h"
diff --git a/src/mongo/s/sharding_initialization.h b/src/mongo/s/sharding_initialization.h
index 94973f0f24f..33e3046074c 100644
--- a/src/mongo/s/sharding_initialization.h
+++ b/src/mongo/s/sharding_initialization.h
@@ -51,9 +51,8 @@ using ShardingCatalogManagerBuilder = stdx::function<std::unique_ptr<ShardingCat
     ShardingCatalogClient*, std::unique_ptr<executor::TaskExecutor>)>;
 
 namespace rpc {
-class ShardingEgressMetadataHook;
-using ShardingEgressMetadataHookBuilder =
-    stdx::function<std::unique_ptr<ShardingEgressMetadataHook>()>;
+class EgressMetadataHook;
+using ShardingEgressMetadataHookBuilder = stdx::function<std::unique_ptr<EgressMetadataHook>()>;
 }  // namespace rpc
 
 /**