status: Show list of loaded language modules

When querying the '/status' node in the control API, display the list of
currently loaded modules.

So we now get something like

  {
      "modules": {
          "python": [
              {
                  "version": "3.12.3",
                   "lib": "/opt/unit/modules/python.unit.so"
              },
              {
                  "version": "3.12.1",
                  "lib": "/opt/unit/modules/python-3.12.1.unit.so"
              }
          ],

          "wasm": {
              "version": "0.1",
              "lib": "/opt/unit/modules/wasm.unit.so"
          },

          "wasm-wasi-component": {
              "version": "0.1",
              "lib": "/opt/unit/modules/wasm_wasi_component.unit.so"
          }
      },

      ...
  }

This can be useful for debugging to show exactly what modules Unit has
loaded _and_ from where.

Closes: https://github.com/nginx/unit/issues/1343
Signed-off-by: Andrew Clayton <a.clayton@nginx.com>

1 files changed, 94 insertions, 8 deletions

diff --git a/src/nxt_status.c b/src/nxt_status.c
index 957bc34e..b48ec743 100644
--- a/src/nxt_status.c
+++ b/src/nxt_status.c
@@ -6,18 +6,27 @@
 #include <nxt_main.h>
 #include <nxt_conf.h>
 #include <nxt_status.h>
+#include <nxt_application.h>
 
 
 nxt_conf_value_t *
 nxt_status_get(nxt_status_report_t *report, nxt_mp_t *mp)
 {
-    size_t            i;
-    uint32_t          idx = 0;
-    nxt_str_t         name;
-    nxt_int_t         ret;
-    nxt_status_app_t  *app;
-    nxt_conf_value_t  *status, *obj, *apps, *app_obj;
-
+    size_t                 i, nr_langs;
+    uint16_t               lang_cnts[NXT_APP_UNKNOWN] = { 1 };
+    uint32_t               idx = 0;
+    nxt_str_t              name;
+    nxt_int_t              ret;
+    nxt_array_t            *langs;
+    nxt_thread_t           *thr;
+    nxt_app_type_t         type, prev_type;
+    nxt_status_app_t       *app;
+    nxt_conf_value_t       *status, *obj, *mods, *apps, *app_obj, *mod_obj;
+    nxt_app_lang_module_t  *modules;
+
+    static const nxt_str_t  modules_str = nxt_string("modules");
+    static const nxt_str_t  version_str = nxt_string("version");
+    static const nxt_str_t  lib_str = nxt_string("lib");
     static const nxt_str_t  conns_str = nxt_string("connections");
     static const nxt_str_t  acc_str = nxt_string("accepted");
     static const nxt_str_t  active_str = nxt_string("active");
@@ -30,11 +39,88 @@ nxt_status_get(nxt_status_report_t *report, nxt_mp_t *mp)
     static const nxt_str_t  run_str = nxt_string("running");
     static const nxt_str_t  start_str = nxt_string("starting");
 
-    status = nxt_conf_create_object(mp, 3);
+    status = nxt_conf_create_object(mp, 4);
     if (nxt_slow_path(status == NULL)) {
         return NULL;
     }
 
+    thr = nxt_thread();
+    langs = thr->runtime->languages;
+
+    modules = langs->elts;
+    /*
+     * We need to count the number of unique languages to correctly
+     * allocate the below mods object.
+     *
+     * We also need to count how many of each language.
+     *
+     * Start by skipping past NXT_APP_EXTERNAL which is always the
+     * first entry.
+     */
+    for (i = 1, nr_langs = 0, prev_type = NXT_APP_UNKNOWN; i < langs->nelts;
+         i++)
+    {
+        type = modules[i].type;
+
+        lang_cnts[type]++;
+
+        if (type == prev_type) {
+            continue;
+        }
+
+        nr_langs++;
+        prev_type = type;
+    }
+
+    mods = nxt_conf_create_object(mp, nr_langs);
+    if (nxt_slow_path(mods == NULL)) {
+        return NULL;
+    }
+
+    nxt_conf_set_member(status, &modules_str, mods, idx++);
+
+    i = 1;
+    obj = mod_obj = NULL;
+    prev_type = NXT_APP_UNKNOWN;
+    for (size_t l = 0, a = 0; i < langs->nelts; i++) {
+        nxt_str_t  item, mod_name;
+
+        type = modules[i].type;
+        if (type != prev_type) {
+            a = 0;
+
+            if (lang_cnts[type] == 1) {
+                mod_obj = nxt_conf_create_object(mp, 2);
+                obj = mod_obj;
+            } else {
+                mod_obj = nxt_conf_create_array(mp, lang_cnts[type]);
+            }
+
+            if (nxt_slow_path(mod_obj == NULL)) {
+                return NULL;
+            }
+
+            mod_name.start = (u_char *)modules[i].name;
+            mod_name.length = strlen(modules[i].name);
+            nxt_conf_set_member(mods, &mod_name, mod_obj, l++);
+        }
+
+        if (lang_cnts[type] > 1) {
+            obj = nxt_conf_create_object(mp, 2);
+            nxt_conf_set_element(mod_obj, a++, obj);
+        }
+
+        item.start = modules[i].version;
+        item.length = nxt_strlen(modules[i].version);
+        nxt_conf_set_member_string(obj, &version_str, &item, 0);
+
+        item.start = (u_char *)modules[i].file;
+        item.length = strlen(modules[i].file);
+        nxt_conf_set_member_string(obj, &lib_str, &item, 1);
+
+        prev_type = type;
+    }
+
     obj = nxt_conf_create_object(mp, 4);
     if (nxt_slow_path(obj == NULL)) {
         return NULL;