Refactor of process management.

The process abstraction has changed to:

  setup(task, process)
  start(task, process_data)
  prefork(task, process, mp)

The prefork() occurs in the main process right before fork.

The file src/nxt_main_process.c is completely free of process
specific logic.

The creation of a process now supports a PROCESS_CREATED state.  The
The setup() function of each process can set its state to either
created or ready.  If created, a MSG_PROCESS_CREATED is sent to main
process, where external setup can be done (required for rootfs under
container).

The core processes (discovery, controller and router) doesn't need
external setup, then they all proceeds to their start() function
straight away.

In the case of applications, the load of the module happens at the
process setup() time and The module's init() function has changed
to be the start() of the process.

The module API has changed to:

  setup(task, process, conf)
  start(task, data)

As a direct benefit of the PROCESS_CREATED message, the clone(2) of
processes using pid namespaces now doesn't need to create a pipe
to make the child block until parent setup uid/gid mappings nor it
needs to receive the child pid.

1 files changed, 35 insertions, 9 deletions

diff --git a/src/nxt_router.c b/src/nxt_router.c
index b4cba08b..788199c7 100644
--- a/src/nxt_router.c
+++ b/src/nxt_router.c
@@ -75,6 +75,9 @@ struct nxt_port_select_state_s {
 
 typedef struct nxt_port_select_state_s nxt_port_select_state_t;
 
+static nxt_int_t nxt_router_prefork(nxt_task_t *task, nxt_process_t *process,
+    nxt_mp_t *mp);
+static nxt_int_t nxt_router_start(nxt_task_t *task, nxt_process_data_t *data);
 static void nxt_router_greet_controller(nxt_task_t *task,
     nxt_port_t *controller_port);
 
@@ -268,8 +271,8 @@ static const nxt_str_t  *nxt_app_msg_prefix[] = {
 };
 
 
-nxt_port_handlers_t  nxt_router_process_port_handlers = {
-    .quit         = nxt_worker_process_quit_handler,
+static const nxt_port_handlers_t  nxt_router_process_port_handlers = {
+    .quit         = nxt_signal_quit_handler,
     .new_port     = nxt_router_new_port_handler,
     .change_file  = nxt_port_change_log_file_handler,
     .mmap         = nxt_port_mmap_handler,
@@ -282,8 +285,29 @@ nxt_port_handlers_t  nxt_router_process_port_handlers = {
 };
 
 
-nxt_int_t
-nxt_router_start(nxt_task_t *task, void *data)
+const nxt_process_init_t  nxt_router_process = {
+    .name           = "router",
+    .type           = NXT_PROCESS_ROUTER,
+    .prefork        = nxt_router_prefork,
+    .restart        = 1,
+    .setup          = nxt_process_core_setup,
+    .start          = nxt_router_start,
+    .port_handlers  = &nxt_router_process_port_handlers,
+    .signals        = nxt_process_signals,
+};
+
+
+static nxt_int_t
+nxt_router_prefork(nxt_task_t *task, nxt_process_t *process, nxt_mp_t *mp)
+{
+    nxt_runtime_stop_app_processes(task, task->thread->runtime);
+
+    return NXT_OK;
+}
+
+
+static nxt_int_t
+nxt_router_start(nxt_task_t *task, nxt_process_data_t *data)
 {
     nxt_int_t      ret;
     nxt_port_t     *controller_port;
@@ -292,6 +316,8 @@ nxt_router_start(nxt_task_t *task, void *data)
 
     rt = task->thread->runtime;
 
+    nxt_log(task, NXT_LOG_INFO, "router started");
+
 #if (NXT_TLS)
     rt->tls = nxt_service_get(rt->services, "SSL/TLS", "OpenSSL");
     if (nxt_slow_path(rt->tls == NULL)) {
@@ -382,8 +408,8 @@ nxt_router_start_app_process_handler(nxt_task_t *task, nxt_port_t *port,
         goto failed;
     }
 
-    ret = nxt_port_socket_write(task, main_port, NXT_PORT_MSG_START_WORKER, -1,
-                                stream, port->id, b);
+    ret = nxt_port_socket_write(task, main_port, NXT_PORT_MSG_START_PROCESS,
+                                -1, stream, port->id, b);
 
     if (nxt_slow_path(ret != NXT_OK)) {
         nxt_port_rpc_cancel(task, port, stream);
@@ -862,7 +888,7 @@ nxt_router_new_port_handler(nxt_task_t *task, nxt_port_recv_msg_t *msg)
     }
 
     if (msg->u.new_port == NULL
-        || msg->u.new_port->type != NXT_PROCESS_WORKER)
+        || msg->u.new_port->type != NXT_PROCESS_APP)
     {
         msg->port_msg.type = _NXT_PORT_MSG_RPC_ERROR;
     }
@@ -2400,8 +2426,8 @@ nxt_router_app_rpc_create(nxt_task_t *task,
         goto fail;
     }
 
-    ret = nxt_port_socket_write(task, main_port, NXT_PORT_MSG_START_WORKER, -1,
-                                stream, router_port->id, b);
+    ret = nxt_port_socket_write(task, main_port, NXT_PORT_MSG_START_PROCESS,
+                                -1, stream, router_port->id, b);
 
     if (nxt_slow_path(ret != NXT_OK)) {
         nxt_port_rpc_cancel(task, router_port, stream);