add libstorage call and tests

library/libstorage.h

@@ -120,6 +120,13 @@ extern "C"
         StorageCallback callback,
         void *userData);
 
+    // Returns node metrics in the Logos openmetrics-compatible
+    // format (https://github.com/logos-co/openmetrics-module).
+    int storage_get_metrics(
+        void *ctx,
+        StorageCallback callback,
+        void *userData);
+
     // Set the log level at run time.
     // `logLevel` can be one of:
     // TRACE, DEBUG, INFO, NOTICE, WARN, ERROR or FATAL

library/libstorage.nim

@@ -185,6 +185,19 @@ proc storage_peer_id(
 
   return callback.okOrError(res, userData)
 
+proc storage_get_metrics(
+    ctx: ptr StorageContext, callback: StorageCallback, userData: pointer
+): cint {.dynlib, exportc.} =
+  initializeLibrary()
+  checkLibstorageParams(ctx, callback, userData)
+
+  let reqContent = NodeInfoRequest.createShared(NodeInfoMsgType.METRICS)
+  let res = storage_context.sendRequestToStorageThread(
+    ctx, RequestType.INFO, reqContent, callback, userData
+  )
+
+  return callback.okOrError(res, userData)
+
 ## Set the log level of the library at runtime.
 ## It uses updateLogLevel which is a synchronous proc and
 ## cannot be used inside an async context because of gcsafe issue.

library/storage_thread_requests/requests/node_info_request.nim

@@ -5,6 +5,8 @@ import chronos
 import chronicles
 import confutils
 import codexdht/discv5/spr
+import metrics
+import ../../logosmetrics
 import ../../../storage/conf
 import ../../../storage/rest/json
 import ../../../storage/node
@@ -18,6 +20,8 @@ type NodeInfoMsgType* = enum
   REPO
   SPR
   PEERID
+  # Not sure this belongs here but for now OK.
+  METRICS
 
 type NodeInfoRequest* = object
   operation: NodeInfoMsgType
@@ -74,3 +78,6 @@ proc process*(
       error "Failed to get PEERID.", error = res.error
       return err($res.error)
     return res
+  of METRICS:
+    {.cast(gcsafe).}:
+      return ok($defaultRegistry.toJson())

tests/cbindings/storage.c

@@ -841,6 +841,36 @@ int check_toggle_private_queries(void *storage_ctx)
     return RET_OK;
 }
 
+int check_get_metrics(void *storage_ctx)
+{
+    Resp *r = alloc_resp();
+    char *res = NULL;
+
+    if (storage_get_metrics(storage_ctx, (StorageCallback)callback, r) != RET_OK)
+    {
+        free_resp(r);
+        return RET_ERR;
+    }
+
+    int ret = is_resp_ok(r, &res);
+    if (ret != RET_OK)
+    {
+        free(res);
+        return ret;
+    }
+
+    // Checks that response contains a metric we are SURE must exist
+    if (strstr(res, "nim_gc_heap_instance_occupied_bytes") == NULL)
+    {
+        fprintf(stderr, "get_metrics missing expected metric\n");
+        free(res);
+        return RET_ERR;
+    }
+
+    free(res);
+    return RET_OK;
+}
+
 // TODO: implement check_fetch
 // It is a bit complicated because it requires two nodes
 // connected together to fetch from peers.
@@ -894,6 +924,7 @@ int main(void)
 
     RUN_TEST(check_toggle_private_queries(storage_ctx));
     RUN_TEST(update_log_level(storage_ctx, "TRACE"));
+    RUN_TEST(check_get_metrics(storage_ctx));
     RUN_TEST(cleanup(storage_ctx));
 
     END_SUITE