server: change hot restart parent<-->child protocol, remove stats shared memory

include/envoy/server/hot_restart.h

@@ -52,9 +52,9 @@ class HotRestart {
   virtual void getParentStats(GetParentStatsInfo& info) PURE;
 
   /**
-   * Initialize the restarter after primary server initialization begins. The hot restart
-   * implementation needs to be created early to deal with shared memory, logging, etc. so
-   * late initialization of needed interfaces is done here.
+   * Initialize the parent logic of our restarter. Meant to be called after initialization of a
+   * new child has begun. The hot restart implementation needs to be created early to deal with
+   * shared memory, logging, etc. so late initialization of needed interfaces is done here.
    */
   virtual void initialize(Event::Dispatcher& dispatcher, Server::Instance& server) PURE;
 
@@ -66,12 +66,12 @@ class HotRestart {
   virtual void shutdownParentAdmin(ShutdownParentAdminInfo& info) PURE;
 
   /**
-   * Tell our parent to gracefully terminate itself.
+   * Tell our parent process to gracefully terminate itself.
    */
   virtual void terminateParent() PURE;
 
   /**
-   * Shutdown the hot restarter.
+   * Shutdown the half of our hot restarter that acts as a parent.
    */
   virtual void shutdown() PURE;
 

source/server/BUILD

@@ -108,11 +108,52 @@ envoy_cc_library(
     ],
 )
 
+envoy_cc_library(
+    name = "hot_restarting_base",
+    srcs = envoy_select_hot_restart(["hot_restarting_base.cc"]),
+    hdrs = envoy_select_hot_restart(["hot_restarting_base.h"]),
+    deps = [
+        "//include/envoy/api:os_sys_calls_interface",
+        "//include/envoy/event:dispatcher_interface",
+        "//include/envoy/event:file_event_interface",
+        "//include/envoy/server:hot_restart_interface",
+        "//include/envoy/server:instance_interface",
+        "//include/envoy/server:options_interface",
+        "//source/common/api:os_sys_calls_lib",
+        "//source/common/common:assert_lib",
+        "//source/common/common:block_memory_hash_set_lib",
+        "//source/common/common:utility_lib",
+        "//source/common/network:utility_lib",
+        "//source/common/stats:raw_stat_data_lib",
+        "//source/common/stats:stats_options_lib",
+    ],
+)
+
+envoy_cc_library(
+    name = "hot_restarting_child",
+    srcs = envoy_select_hot_restart(["hot_restarting_child.cc"]),
+    hdrs = envoy_select_hot_restart(["hot_restarting_child.h"]),
+    deps = [
+        ":hot_restarting_base",
+    ],
+)
+
+envoy_cc_library(
+    name = "hot_restarting_parent",
+    srcs = envoy_select_hot_restart(["hot_restarting_parent.cc"]),
+    hdrs = envoy_select_hot_restart(["hot_restarting_parent.h"]),
+    deps = [
+        ":hot_restarting_base",
+    ],
+)
+
 envoy_cc_library(
     name = "hot_restart_lib",
     srcs = envoy_select_hot_restart(["hot_restart_impl.cc"]),
     hdrs = envoy_select_hot_restart(["hot_restart_impl.h"]),
     deps = [
+        ":hot_restarting_child",
+        ":hot_restarting_parent",
         "//include/envoy/api:os_sys_calls_interface",
         "//include/envoy/event:dispatcher_interface",
         "//include/envoy/event:file_event_interface",
@@ -122,8 +163,6 @@ envoy_cc_library(
         "//source/common/api:os_sys_calls_lib",
         "//source/common/common:assert_lib",
         "//source/common/common:block_memory_hash_set_lib",
-        "//source/common/common:utility_lib",
-        "//source/common/network:utility_lib",
         "//source/common/stats:raw_stat_data_lib",
         "//source/common/stats:stats_options_lib",
     ],