From 6914878043a8d460d071a32221fb237686e51d22 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Magnus=20B=C3=A4ck?= <magnus.back@axis.com>
Date: Tue, 11 Jun 2024 23:36:21 +0200
Subject: [PATCH] fix(otelgorm): Make metric reporting work with prepared
 statements

Previously we only initialized metrics reporting by calling
otelsql.ReportDBStatsMetrics if the gorm.DB.ConnPool interface
pointer we received happened to be a *sql.DB. This was often
the case, but not if prepared statements were enabled (and
possibly in other circumstances too). This caused metrics
reporting to be silently disabled. We fix this by calling
gorm.DB.DB whose sole purpose is to extract the underlying
*sql.DB.
---
 otelgorm/otelgorm.go | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/otelgorm/otelgorm.go b/otelgorm/otelgorm.go
index 41c070ca..921d1b43 100644
--- a/otelgorm/otelgorm.go
+++ b/otelgorm/otelgorm.go
@@ -55,8 +55,8 @@ type gormRegister interface {
 
 func (p otelPlugin) Initialize(db *gorm.DB) (err error) {
 	if !p.excludeMetrics {
-		if db, ok := db.ConnPool.(*sql.DB); ok {
-			otelsql.ReportDBStatsMetrics(db)
+		if sqlDB, err := db.DB(); err == nil {
+			otelsql.ReportDBStatsMetrics(sqlDB)
 		}
 	}