Implemented basic statistics API.

14 files changed, 459 insertions, 16 deletions

diff --git a/auto/sources b/auto/sources
index 560f3bf3..8548f812 100644
--- a/auto/sources
+++ b/auto/sources
@@ -85,6 +85,7 @@ NXT_LIB_SRCS=" \
     src/nxt_router.c \
     src/nxt_router_access_log.c \
     src/nxt_h1proto.c \
+    src/nxt_status.c \
     src/nxt_http_request.c \
     src/nxt_http_response.c \
     src/nxt_http_error.c \
diff --git a/docs/changes.xml b/docs/changes.xml
index 586063db..c3496715 100644
--- a/docs/changes.xml
+++ b/docs/changes.xml
@@ -86,6 +86,12 @@ customizable access log format.
 </para>
 </change>
 
+<change type="feature">
+<para>
+basic statistics API.
+</para>
+</change>
+
 <change type="bugfix">
 <para>
 an index file that didn't contain a file extension was incorrectly
diff --git a/src/nxt_conf.c b/src/nxt_conf.c
index a44b8c75..c6312f3d 100644
--- a/src/nxt_conf.c
+++ b/src/nxt_conf.c
@@ -278,6 +278,20 @@ nxt_conf_set_member(nxt_conf_value_t *object, nxt_str_t *name,
 }
 
 
+nxt_int_t
+nxt_conf_set_member_dup(nxt_conf_value_t *object, nxt_mp_t *mp, nxt_str_t *name,
+    nxt_conf_value_t *value, uint32_t index)
+{
+    nxt_conf_object_member_t  *member;
+
+    member = &object->u.object->members[index];
+
+    member->value = *value;
+
+    return nxt_conf_set_string_dup(&member->name, mp, name);
+}
+
+
 void
 nxt_conf_set_member_string(nxt_conf_value_t *object, nxt_str_t *name,
     nxt_str_t *value, uint32_t index)
diff --git a/src/nxt_conf.h b/src/nxt_conf.h
index f95b61c1..c8a276c0 100644
--- a/src/nxt_conf.h
+++ b/src/nxt_conf.h
@@ -127,6 +127,8 @@ NXT_EXPORT nxt_uint_t nxt_conf_object_members_count(nxt_conf_value_t *value);
 nxt_conf_value_t *nxt_conf_create_object(nxt_mp_t *mp, nxt_uint_t count);
 void nxt_conf_set_member(nxt_conf_value_t *object, nxt_str_t *name,
     const nxt_conf_value_t *value, uint32_t index);
+nxt_int_t nxt_conf_set_member_dup(nxt_conf_value_t *object, nxt_mp_t *mp,
+    nxt_str_t *name, nxt_conf_value_t *value, uint32_t index);
 void nxt_conf_set_member_string(nxt_conf_value_t *object, nxt_str_t *name,
     nxt_str_t *value, uint32_t index);
 nxt_int_t nxt_conf_set_member_string_dup(nxt_conf_value_t *object, nxt_mp_t *mp,
diff --git a/src/nxt_conn.h b/src/nxt_conn.h
index a443601f..8a703e9a 100644
--- a/src/nxt_conn.h
+++ b/src/nxt_conn.h
@@ -160,6 +160,7 @@ struct nxt_conn_s {
     uint8_t                       block_read;   /* 1 bit */
     uint8_t                       block_write;  /* 1 bit */
     uint8_t                       delayed;      /* 1 bit */
+    uint8_t                       idle;         /* 1 bit */
 
 #define NXT_CONN_SENDFILE_OFF     0
 #define NXT_CONN_SENDFILE_ON      1
@@ -294,6 +295,28 @@ NXT_EXPORT void nxt_event_conn_job_sendfile(nxt_task_t *task,
     } while (0)
 
 
+#define nxt_conn_idle(engine, c)                                              \
+    do {                                                                      \
+        nxt_event_engine_t  *e = engine;                                      \
+                                                                              \
+        nxt_queue_insert_head(&e->idle_connections, &c->link);                \
+                                                                              \
+        c->idle = 1;                                                          \
+        e->idle_conns_cnt++;                                                  \
+    } while (0)
+
+
+#define nxt_conn_active(engine, c)                                            \
+    do {                                                                      \
+        nxt_event_engine_t  *e = engine;                                      \
+                                                                              \
+        nxt_queue_remove(&c->link);                                           \
+                                                                              \
+        c->idle = 0;                                                          \
+        e->idle_conns_cnt--;                                                  \
+    } while (0)
+
+
 extern nxt_conn_io_t             nxt_unix_conn_io;
 
 
diff --git a/src/nxt_conn_accept.c b/src/nxt_conn_accept.c
index 77c44c58..720c7b64 100644
--- a/src/nxt_conn_accept.c
+++ b/src/nxt_conn_accept.c
@@ -187,7 +187,8 @@ nxt_conn_io_accept(nxt_task_t *task, void *obj, void *data)
 void
 nxt_conn_accept(nxt_task_t *task, nxt_listen_event_t *lev, nxt_conn_t *c)
 {
-    nxt_conn_t  *next;
+    nxt_conn_t          *next;
+    nxt_event_engine_t  *engine;
 
     nxt_sockaddr_text(c->remote);
 
@@ -195,7 +196,11 @@ nxt_conn_accept(nxt_task_t *task, nxt_listen_event_t *lev, nxt_conn_t *c)
               (size_t) c->remote->address_length,
               nxt_sockaddr_address(c->remote));
 
-    nxt_queue_insert_head(&task->thread->engine->idle_connections, &c->link);
+    engine = task->thread->engine;
+
+    engine->accepted_conns_cnt++;
+
+    nxt_conn_idle(engine, c);
 
     c->listen = lev;
     lev->count++;
diff --git a/src/nxt_conn_close.c b/src/nxt_conn_close.c
index 7c130309..92bd8d1b 100644
--- a/src/nxt_conn_close.c
+++ b/src/nxt_conn_close.c
@@ -119,6 +119,8 @@ nxt_conn_close_handler(nxt_task_t *task, void *obj, void *data)
         nxt_socket_close(task, c->socket.fd);
         c->socket.fd = -1;
 
+        engine->closed_conns_cnt++;
+
         if (timers_pending == 0) {
             nxt_work_queue_add(&engine->fast_work_queue,
                                c->write_state->ready_handler,
@@ -137,8 +139,9 @@ nxt_conn_close_handler(nxt_task_t *task, void *obj, void *data)
 static void
 nxt_conn_close_timer_handler(nxt_task_t *task, void *obj, void *data)
 {
-    nxt_conn_t   *c;
-    nxt_timer_t  *timer;
+    nxt_conn_t          *c;
+    nxt_timer_t         *timer;
+    nxt_event_engine_t  *engine;
 
     timer = obj;
 
@@ -146,13 +149,16 @@ nxt_conn_close_timer_handler(nxt_task_t *task, void *obj, void *data)
 
     nxt_debug(task, "conn close timer handler fd:%d", c->socket.fd);
 
+    engine = task->thread->engine;
+
     if (c->socket.fd != -1) {
         nxt_socket_close(task, c->socket.fd);
         c->socket.fd = -1;
+
+        engine->closed_conns_cnt++;
     }
 
-    nxt_work_queue_add(&task->thread->engine->fast_work_queue,
-                       c->write_state->ready_handler,
+    nxt_work_queue_add(&engine->fast_work_queue, c->write_state->ready_handler,
                        task, c, c->socket.data);
 }
 
diff --git a/src/nxt_controller.c b/src/nxt_controller.c
index e1e9fade..09168821 100644
--- a/src/nxt_controller.c
+++ b/src/nxt_controller.c
@@ -9,6 +9,7 @@
 #include <nxt_runtime.h>
 #include <nxt_main_process.h>
 #include <nxt_conf.h>
+#include <nxt_status.h>
 #include <nxt_cert.h>
 
 
@@ -85,6 +86,12 @@ static void nxt_controller_process_request(nxt_task_t *task,
 static void nxt_controller_process_config(nxt_task_t *task,
     nxt_controller_request_t *req, nxt_str_t *path);
 static nxt_bool_t nxt_controller_check_postpone_request(nxt_task_t *task);
+static void nxt_controller_process_status(nxt_task_t *task,
+    nxt_controller_request_t *req);
+static void nxt_controller_status_handler(nxt_task_t *task,
+    nxt_port_recv_msg_t *msg, void *data);
+static void nxt_controller_status_response(nxt_task_t *task,
+    nxt_controller_request_t *req, nxt_str_t *path);
 #if (NXT_TLS)
 static void nxt_controller_process_cert(nxt_task_t *task,
     nxt_controller_request_t *req, nxt_str_t *path);
@@ -120,6 +127,7 @@ static nxt_uint_t              nxt_controller_router_ready;
 static nxt_controller_conf_t   nxt_controller_conf;
 static nxt_queue_t             nxt_controller_waiting_requests;
 static nxt_bool_t              nxt_controller_waiting_init_conf;
+static nxt_conf_value_t        *nxt_controller_status;
 
 
 static const nxt_event_conn_state_t  nxt_controller_conn_read_state;
@@ -1035,6 +1043,7 @@ nxt_controller_process_request(nxt_task_t *task, nxt_controller_request_t *req)
     static nxt_str_t certificates = nxt_string("certificates");
 #endif
     static nxt_str_t config = nxt_string("config");
+    static nxt_str_t status = nxt_string("status");
 
     c = req->conn;
     path = req->parser.path;
@@ -1058,6 +1067,32 @@ nxt_controller_process_request(nxt_task_t *task, nxt_controller_request_t *req)
         return;
     }
 
+    nxt_memzero(&resp, sizeof(nxt_controller_response_t));
+
+    if (nxt_str_start(&path, "/status", 7)
+        && (path.length == 7 || path.start[7] == '/'))
+    {
+        if (!nxt_str_eq(&req->parser.method, "GET", 3)) {
+            goto invalid_method;
+        }
+
+        if (nxt_controller_status == NULL) {
+            nxt_controller_process_status(task, req);
+            return;
+        }
+
+        if (path.length == 7) {
+            path.length = 1;
+
+        } else {
+            path.length -= 7;
+            path.start += 7;
+        }
+
+        nxt_controller_status_response(task, req, &path);
+        return;
+    }
+
 #if (NXT_TLS)
 
     if (nxt_str_start(&path, "/certificates", 13)
@@ -1085,15 +1120,18 @@ nxt_controller_process_request(nxt_task_t *task, nxt_controller_request_t *req)
         return;
     }
 
-    nxt_memzero(&resp, sizeof(nxt_controller_response_t));
-
     if (path.length == 1 && path.start[0] == '/') {
 
         if (!nxt_str_eq(&req->parser.method, "GET", 3)) {
             goto invalid_method;
         }
 
-        count = 1;
+        if (nxt_controller_status == NULL) {
+            nxt_controller_process_status(task, req);
+            return;
+        }
+
+        count = 2;
 #if (NXT_TLS)
         count++;
 #endif
@@ -1114,7 +1152,8 @@ nxt_controller_process_request(nxt_task_t *task, nxt_controller_request_t *req)
         nxt_conf_set_member(value, &certificates, certs, i++);
 #endif
 
-        nxt_conf_set_member(value, &config, nxt_controller_conf.root, i);
+        nxt_conf_set_member(value, &config, nxt_controller_conf.root, i++);
+        nxt_conf_set_member(value, &status, nxt_controller_status, i);
 
         resp.status = 200;
         resp.conf = value;
@@ -1451,6 +1490,128 @@ nxt_controller_check_postpone_request(nxt_task_t *task)
 }
 
 
+static void
+nxt_controller_process_status(nxt_task_t *task, nxt_controller_request_t *req)
+{
+    uint32_t                   stream;
+    nxt_int_t                  rc;
+    nxt_port_t                 *router_port, *controller_port;
+    nxt_runtime_t              *rt;
+    nxt_controller_response_t  resp;
+
+    if (nxt_controller_check_postpone_request(task)) {
+        nxt_queue_insert_tail(&nxt_controller_waiting_requests, &req->link);
+        return;
+    }
+
+    rt = task->thread->runtime;
+
+    router_port = rt->port_by_type[NXT_PROCESS_ROUTER];
+
+    nxt_assert(router_port != NULL);
+    nxt_assert(nxt_controller_router_ready);
+
+    controller_port = rt->port_by_type[NXT_PROCESS_CONTROLLER];
+
+    stream = nxt_port_rpc_register_handler(task, controller_port,
+                                           nxt_controller_status_handler,
+                                           nxt_controller_status_handler,
+                                           router_port->pid, req);
+    if (nxt_slow_path(stream == 0)) {
+        goto fail;
+    }
+
+    rc = nxt_port_socket_write(task, router_port, NXT_PORT_MSG_STATUS,
+                               -1, stream, controller_port->id, NULL);
+
+    if (nxt_slow_path(rc != NXT_OK)) {
+        nxt_port_rpc_cancel(task, controller_port, stream);
+
+        goto fail;
+    }
+
+    nxt_queue_insert_head(&nxt_controller_waiting_requests, &req->link);
+    return;
+
+fail:
+
+    nxt_memzero(&resp, sizeof(nxt_controller_response_t));
+
+    resp.status = 500;
+    resp.title = (u_char *) "Failed to get status.";
+    resp.offset = -1;
+
+    nxt_controller_response(task, req, &resp);
+    return;
+}
+
+
+static void
+nxt_controller_status_handler(nxt_task_t *task, nxt_port_recv_msg_t *msg,
+    void *data)
+{
+    nxt_conf_value_t           *status;
+    nxt_controller_request_t   *req;
+    nxt_controller_response_t  resp;
+
+    nxt_debug(task, "controller status handler");
+
+    req = data;
+
+    if (msg->port_msg.type == NXT_PORT_MSG_RPC_READY) {
+        status = nxt_status_get((nxt_status_report_t *) msg->buf->mem.pos,
+                                req->conn->mem_pool);
+    } else {
+        status = NULL;
+    }
+
+    if (status == NULL) {
+        nxt_queue_remove(&req->link);
+
+        nxt_memzero(&resp, sizeof(nxt_controller_response_t));
+
+        resp.status = 500;
+        resp.title = (u_char *) "Failed to get status.";
+        resp.offset = -1;
+
+        nxt_controller_response(task, req, &resp);
+    }
+
+    nxt_controller_status = status;
+
+    nxt_controller_flush_requests(task);
+
+    nxt_controller_status = NULL;
+}
+
+
+static void
+nxt_controller_status_response(nxt_task_t *task, nxt_controller_request_t *req,
+    nxt_str_t *path)
+{
+    nxt_conf_value_t           *status;
+    nxt_controller_response_t  resp;
+
+    status = nxt_conf_get_path(nxt_controller_status, path);
+
+    nxt_memzero(&resp, sizeof(nxt_controller_response_t));
+
+    if (status == NULL) {
+        resp.status = 404;
+        resp.title = (u_char *) "Invalid path.";
+        resp.offset = -1;
+
+        nxt_controller_response(task, req, &resp);
+        return;
+    }
+
+    resp.status = 200;
+    resp.conf = status;
+
+    nxt_controller_response(task, req, &resp);
+}
+
+
 #if (NXT_TLS)
 
 static void
diff --git a/src/nxt_event_engine.h b/src/nxt_event_engine.h
index 91cfc0aa..4153742d 100644
--- a/src/nxt_event_engine.h
+++ b/src/nxt_event_engine.h
@@ -483,6 +483,10 @@ struct nxt_event_engine_s {
     nxt_queue_t                idle_connections;
     nxt_array_t                *mem_cache;
 
+    nxt_atomic_uint_t          accepted_conns_cnt;
+    nxt_atomic_uint_t          idle_conns_cnt;
+    nxt_atomic_uint_t          closed_conns_cnt;
+
     nxt_queue_link_t           link;
     // STUB: router link
     nxt_queue_link_t           link0;
diff --git a/src/nxt_h1proto.c b/src/nxt_h1proto.c
index 1473aaa0..852b4866 100644
--- a/src/nxt_h1proto.c
+++ b/src/nxt_h1proto.c
@@ -478,7 +478,7 @@ nxt_h1p_conn_request_init(nxt_task_t *task, void *obj, void *data)
 
     nxt_debug(task, "h1p conn request init");
 
-    nxt_queue_remove(&c->link);
+    nxt_conn_active(task->thread->engine, c);
 
     r = nxt_http_request_create(task);
 
@@ -1739,7 +1739,7 @@ nxt_h1p_conn_close(nxt_task_t *task, void *obj, void *data)
 
     nxt_debug(task, "h1p conn close");
 
-    nxt_queue_remove(&c->link);
+    nxt_conn_active(task->thread->engine, c);
 
     nxt_h1p_shutdown(task, c);
 }
@@ -1754,7 +1754,7 @@ nxt_h1p_conn_error(nxt_task_t *task, void *obj, void *data)
 
     nxt_debug(task, "h1p conn error");
 
-    nxt_queue_remove(&c->link);
+    nxt_conn_active(task->thread->engine, c);
 
     nxt_h1p_shutdown(task, c);
 }
@@ -1801,7 +1801,8 @@ nxt_h1p_keepalive(nxt_task_t *task, nxt_h1proto_t *h1p, nxt_conn_t *c)
     c->sent = 0;
 
     engine = task->thread->engine;
-    nxt_queue_insert_head(&engine->idle_connections, &c->link);
+
+    nxt_conn_idle(engine, c);
 
     if (in == NULL) {
         c->read_state = &nxt_h1p_keepalive_state;
@@ -1855,7 +1856,7 @@ nxt_h1p_idle_close(nxt_task_t *task, void *obj, void *data)
 
     nxt_debug(task, "h1p idle close");
 
-    nxt_queue_remove(&c->link);
+    nxt_conn_active(task->thread->engine, c);
 
     nxt_h1p_idle_response(task, c);
 }
@@ -1874,7 +1875,7 @@ nxt_h1p_idle_timeout(nxt_task_t *task, void *obj, void *data)
     c = nxt_read_timer_conn(timer);
     c->block_read = 1;
 
-    nxt_queue_remove(&c->link);
+    nxt_conn_active(task->thread->engine, c);
 
     nxt_h1p_idle_response(task, c);
 }
diff --git a/src/nxt_port.h b/src/nxt_port.h
index 6b4d3c8f..3a8da5ad 100644
--- a/src/nxt_port.h
+++ b/src/nxt_port.h
@@ -53,6 +53,9 @@ struct nxt_port_handlers_s {
     nxt_port_handler_t  data;
     nxt_port_handler_t  app_restart;
 
+    /* Status report. */
+    nxt_port_handler_t  status;
+
     nxt_port_handler_t  oosm;
     nxt_port_handler_t  shm_ack;
     nxt_port_handler_t  read_queue;
@@ -104,6 +107,7 @@ typedef enum {
 
     _NXT_PORT_MSG_DATA            = nxt_port_handler_idx(data),
     _NXT_PORT_MSG_APP_RESTART     = nxt_port_handler_idx(app_restart),
+    _NXT_PORT_MSG_STATUS          = nxt_port_handler_idx(status),
 
     _NXT_PORT_MSG_OOSM            = nxt_port_handler_idx(oosm),
     _NXT_PORT_MSG_SHM_ACK         = nxt_port_handler_idx(shm_ack),
@@ -145,6 +149,7 @@ typedef enum {
     NXT_PORT_MSG_DATA             = _NXT_PORT_MSG_DATA,
     NXT_PORT_MSG_DATA_LAST        = nxt_msg_last(_NXT_PORT_MSG_DATA),
     NXT_PORT_MSG_APP_RESTART      = nxt_msg_last(_NXT_PORT_MSG_APP_RESTART),
+    NXT_PORT_MSG_STATUS           = nxt_msg_last(_NXT_PORT_MSG_STATUS),
 
     NXT_PORT_MSG_OOSM             = nxt_msg_last(_NXT_PORT_MSG_OOSM),
     NXT_PORT_MSG_SHM_ACK          = nxt_msg_last(_NXT_PORT_MSG_SHM_ACK),
diff --git a/src/nxt_router.c b/src/nxt_router.c
index e1f4f6da..e7723a2d 100644
--- a/src/nxt_router.c
+++ b/src/nxt_router.c
@@ -7,6 +7,7 @@
 
 #include <nxt_router.h>
 #include <nxt_conf.h>
+#include <nxt_status.h>
 #if (NXT_TLS)
 #include <nxt_cert.h>
 #endif
@@ -90,6 +91,8 @@ static void nxt_router_conf_data_handler(nxt_task_t *task,
     nxt_port_recv_msg_t *msg);
 static void nxt_router_app_restart_handler(nxt_task_t *task,
     nxt_port_recv_msg_t *msg);
+static void nxt_router_status_handler(nxt_task_t *task,
+    nxt_port_recv_msg_t *msg);
 static void nxt_router_remove_pid_handler(nxt_task_t *task,
     nxt_port_recv_msg_t *msg);
 
@@ -269,6 +272,7 @@ static const nxt_port_handlers_t  nxt_router_process_port_handlers = {
     .get_mmap     = nxt_router_get_mmap_handler,
     .data         = nxt_router_conf_data_handler,
     .app_restart  = nxt_router_app_restart_handler,
+    .status       = nxt_router_status_handler,
     .remove_pid   = nxt_router_remove_pid_handler,
     .access_log   = nxt_router_access_log_reopen_handler,
     .rpc_ready    = nxt_port_rpc_handler,
@@ -919,6 +923,83 @@ fail:
 
 
 static void
+nxt_router_status_handler(nxt_task_t *task, nxt_port_recv_msg_t *msg)
+{
+    u_char               *p;
+    size_t               alloc;
+    nxt_app_t            *app;
+    nxt_buf_t            *b;
+    nxt_uint_t           type;
+    nxt_port_t           *port;
+    nxt_status_app_t     *app_stat;
+    nxt_event_engine_t   *engine;
+    nxt_status_report_t  *report;
+
+    port = nxt_runtime_port_find(task->thread->runtime,
+                                 msg->port_msg.pid,
+                                 msg->port_msg.reply_port);
+    if (nxt_slow_path(port == NULL)) {
+        nxt_alert(task, "nxt_router_status_handler(): reply port not found");
+        return;
+    }
+
+    alloc = sizeof(nxt_status_report_t);
+
+    nxt_queue_each(app, &nxt_router->apps, nxt_app_t, link) {
+
+        alloc += sizeof(nxt_status_app_t) + app->name.length;
+
+    } nxt_queue_loop;
+
+    b = nxt_buf_mem_alloc(port->mem_pool, alloc, 0);
+    if (nxt_slow_path(b == NULL)) {
+        type = NXT_PORT_MSG_RPC_ERROR;
+        goto fail;
+    }
+
+    report = (nxt_status_report_t *) b->mem.free;
+    b->mem.free = b->mem.end;
+
+    nxt_memzero(report, sizeof(nxt_status_report_t));
+
+    nxt_queue_each(engine, &nxt_router->engines, nxt_event_engine_t, link0) {
+
+        report->accepted_conns += engine->accepted_conns_cnt;
+        report->idle_conns += engine->idle_conns_cnt;
+        report->closed_conns += engine->closed_conns_cnt;
+
+    } nxt_queue_loop;
+
+    report->apps_count = 0;
+    app_stat = report->apps;
+    p = b->mem.end;
+
+    nxt_queue_each(app, &nxt_router->apps, nxt_app_t, link) {
+        p -= app->name.length;
+
+        nxt_memcpy(p, app->name.start, app->name.length);
+
+        app_stat->name.length = app->name.length;
+        app_stat->name.start = (u_char *) (p - b->mem.pos);
+
+        app_stat->active_requests = app->active_requests;
+        app_stat->pending_processes = app->pending_processes;
+        app_stat->processes = app->processes;
+        app_stat->idle_processes = app->idle_processes;
+
+        report->apps_count++;
+        app_stat++;
+    } nxt_queue_loop;
+
+    type = NXT_PORT_MSG_RPC_READY_LAST;
+
+fail:
+
+    nxt_port_socket_write(task, port, type, -1, msg->port_msg.stream, 0, b);
+}
+
+
+static void
 nxt_router_app_process_remove_pid(nxt_task_t *task, nxt_port_t *port,
     void *data)
 {
diff --git a/src/nxt_status.c b/src/nxt_status.c
new file mode 100644
index 00000000..529f6ebb
--- /dev/null
+++ b/src/nxt_status.c
@@ -0,0 +1,102 @@
+
+/*
+ * Copyright (C) NGINX, Inc.
+ */
+
+#include <nxt_main.h>
+#include <nxt_conf.h>
+#include <nxt_status.h>
+
+
+nxt_conf_value_t *
+nxt_status_get(nxt_status_report_t *report, nxt_mp_t *mp)
+{
+    size_t            i;
+    nxt_str_t         name;
+    nxt_int_t         ret;
+    nxt_status_app_t  *app;
+    nxt_conf_value_t  *status, *obj, *apps, *app_obj;
+
+    static nxt_str_t conns_str = nxt_string("connections");
+    static nxt_str_t acc_str = nxt_string("accepted");
+    static nxt_str_t active_str = nxt_string("active");
+    static nxt_str_t idle_str = nxt_string("idle");
+    static nxt_str_t closed_str = nxt_string("closed");
+    static nxt_str_t reqs_str = nxt_string("requests");
+    static nxt_str_t apps_str = nxt_string("applications");
+    static nxt_str_t procs_str = nxt_string("processes");
+    static nxt_str_t run_str = nxt_string("running");
+    static nxt_str_t start_str = nxt_string("starting");
+
+    status = nxt_conf_create_object(mp, 3);
+    if (nxt_slow_path(status == NULL)) {
+        return NULL;
+    }
+
+    obj = nxt_conf_create_object(mp, 4);
+    if (nxt_slow_path(obj == NULL)) {
+        return NULL;
+    }
+
+    nxt_conf_set_member(status, &conns_str, obj, 0);
+
+    nxt_conf_set_member_integer(obj, &acc_str, report->accepted_conns, 0);
+    nxt_conf_set_member_integer(obj, &active_str, report->accepted_conns
+                                                  - report->closed_conns
+                                                  - report->idle_conns, 1);
+    nxt_conf_set_member_integer(obj, &idle_str, report->idle_conns, 2);
+    nxt_conf_set_member_integer(obj, &closed_str, report->closed_conns, 3);
+
+    obj = nxt_conf_create_object(mp, 0);
+    if (nxt_slow_path(obj == NULL)) {
+        return NULL;
+    }
+
+    nxt_conf_set_member(status, &reqs_str, obj, 1);
+
+    apps = nxt_conf_create_object(mp, report->apps_count);
+    if (nxt_slow_path(obj == NULL)) {
+        return NULL;
+    }
+
+    nxt_conf_set_member(status, &apps_str, apps, 2);
+
+    for (i = 0; i < report->apps_count; i++) {
+        app = &report->apps[i];
+
+        app_obj = nxt_conf_create_object(mp, 2);
+        if (nxt_slow_path(app_obj == NULL)) {
+            return NULL;
+        }
+
+        name.length = app->name.length;
+        name.start = nxt_pointer_to(report, (uintptr_t) app->name.start);
+
+        ret = nxt_conf_set_member_dup(apps, mp, &name, app_obj, i);
+        if (nxt_slow_path(ret != NXT_OK)) {
+            return NULL;
+        }
+
+        obj = nxt_conf_create_object(mp, 3);
+        if (nxt_slow_path(app_obj == NULL)) {
+            return NULL;
+        }
+
+        nxt_conf_set_member(app_obj, &procs_str, obj, 0);
+
+        nxt_conf_set_member_integer(obj, &run_str, app->processes, 0);
+        nxt_conf_set_member_integer(obj, &start_str, app->pending_processes, 1);
+        nxt_conf_set_member_integer(obj, &idle_str, app->idle_processes, 2);
+
+        obj = nxt_conf_create_object(mp, 1);
+        if (nxt_slow_path(app_obj == NULL)) {
+            return NULL;
+        }
+
+        nxt_conf_set_member(app_obj, &reqs_str, obj, 1);
+
+        nxt_conf_set_member_integer(obj, &active_str, app->active_requests, 0);
+    }
+
+    return status;
+}
diff --git a/src/nxt_status.h b/src/nxt_status.h
new file mode 100644
index 00000000..b12eabcb
--- /dev/null
+++ b/src/nxt_status.h
@@ -0,0 +1,32 @@
+
+/*
+ * Copyright (C) NGINX, Inc.
+ */
+
+#ifndef _NXT_STATUS_H_INCLUDED_
+#define _NXT_STATUS_H_INCLUDED_
+
+
+typedef struct {
+    nxt_str_t         name;
+    uint32_t          active_requests;
+    uint32_t          pending_processes;
+    uint32_t          processes;
+    uint32_t          idle_processes;
+} nxt_status_app_t;
+
+
+typedef struct {
+    uint64_t          accepted_conns;
+    uint64_t          idle_conns;
+    uint64_t          closed_conns;
+
+    size_t            apps_count;
+    nxt_status_app_t  apps[];
+} nxt_status_report_t;
+
+
+nxt_conf_value_t *nxt_status_get(nxt_status_report_t *report, nxt_mp_t *mp);
+
+
+#endif /* _NXT_STATUS_H_INCLUDED_ */