implement special pre-fork run once mode (#1349)

Author: DrDet

server/database-drivers/adaptor.h

@@ -23,7 +23,7 @@
 class PhpWorker;
 struct net_event_t;
 struct external_driver_connect;
-void generic_event_loop(WorkerType, bool) noexcept;
+void generic_event_loop(WorkerType, bool, bool) noexcept;
 void php_worker_run_net_queue(PhpWorker *);
 bool process_net_event(net_event_t *);
 // endregion
@@ -104,7 +104,7 @@ class Adaptor : vk::not_copyable {
   friend struct ::external_driver_connect;
 
   void create_outbound_connections() noexcept;
-  friend void ::generic_event_loop(WorkerType, bool) noexcept;
+  friend void ::generic_event_loop(WorkerType, bool, bool) noexcept;
 
   void process_external_db_request_net_query(std::unique_ptr<Request> &&request) noexcept;
   friend void ::php_worker_run_net_queue(PhpWorker *);

server/php-engine-vars.cpp

@@ -27,7 +27,7 @@ int master_pid = -1;
 ProcessType process_type = ProcessType::master;
 
 int master_flag = 0; // 1 -- master, 0 -- single process, -1 -- child
-
+bool run_once_prefork_mode = false;
 bool run_once = false;
 int run_once_return_code = 0;
 

server/php-engine-vars.h

@@ -37,7 +37,7 @@ extern int master_pid;
 extern ProcessType process_type;
 
 extern int master_flag;
-
+extern bool run_once_prefork_mode;
 extern bool run_once;
 extern int run_once_return_code;
 

server/php-engine.cpp

@@ -1437,7 +1437,7 @@ void reopen_json_log() {
   }
 }
 
-void generic_event_loop(WorkerType worker_type, bool init_and_listen_rpc_port) noexcept {
+void generic_event_loop(WorkerType worker_type, bool init_and_listen_rpc_port, bool invoke_dummy_self_rpc_request) noexcept {
   if (master_flag && logname_pattern != nullptr) {
     reopen_logs();
     reopen_json_log();
@@ -1468,24 +1468,24 @@ void generic_event_loop(WorkerType worker_type, bool init_and_listen_rpc_port) n
         if (rpc_sfd >= 0) {
           init_listening_connection(rpc_sfd, &ct_php_engine_rpc_server, &rpc_methods);
         }
+      }
 
-        if (run_once) {
-          int pipe_fd[2];
-          pipe(pipe_fd);
+      if (invoke_dummy_self_rpc_request) {
+        int pipe_fd[2];
+        pipe(pipe_fd);
 
-          int read_fd = pipe_fd[0];
-          int write_fd = pipe_fd[1];
+        int read_fd = pipe_fd[0];
+        int write_fd = pipe_fd[1];
 
-          rpc_client_methods.rpc_ready = nullptr;
-          epoll_insert_pipe(pipe_for_read, read_fd, &ct_php_rpc_client, &rpc_client_methods);
+        rpc_client_methods.rpc_ready = nullptr;
+        epoll_insert_pipe(pipe_for_read, read_fd, &ct_php_rpc_client, &rpc_client_methods);
 
-          int q[6];
-          int qsize = 6 * sizeof(int);
-          q[2] = TL_RPC_INVOKE_REQ;
-          for (int i = 0; i < run_once_count; i++) {
-            prepare_rpc_query_raw(i, q, qsize, crc32c_partial);
-            assert (write(write_fd, q, (size_t)qsize) == qsize);
-          }
+        int q[6];
+        int qsize = 6 * sizeof(int);
+        q[2] = TL_RPC_INVOKE_REQ;
+        for (int i = 0; i < run_once_count; i++) {
+          prepare_rpc_query_raw(i, q, qsize, crc32c_partial);
+          assert(write(write_fd, q, (size_t)qsize) == qsize);
         }
       }
 
@@ -1633,7 +1633,7 @@ void start_server() {
   }
 
   worker_global_init(worker_type);
-  generic_event_loop(worker_type, !master_flag);
+  generic_event_loop(worker_type, !master_flag, run_once || run_once_prefork_mode);
 }
 
 void set_instance_cache_memory_limit(size_t limit);
@@ -2454,9 +2454,14 @@ int run_main(int argc, char **argv, php_mode mode) {
   parse_main_args(argc, argv);
 
   if (run_once) {
-    master_flag = 0;
-    rpc_port = -1;
-    setvbuf(stdout, nullptr, _IONBF, 0);
+    if (master_flag) {
+      kprintf("running in special run once pre-fork mode\n");
+      run_once_prefork_mode = true;
+    } else {
+      master_flag = 0;
+      rpc_port = -1;
+      setvbuf(stdout, nullptr, _IONBF, 0);
+    }
   }
 
   if (!master_flag && vk::singleton<HttpServerContext>::get().http_server_enabled()) {