From de4d91514b0d29e16c504f6b3c93d97d113e7f90 Mon Sep 17 00:00:00 2001
From: Kevin Gosse <kevin.gosse@datadoghq.com>
Date: Fri, 8 Mar 2024 10:08:18 +0100
Subject: [PATCH] Warm up the query string obfuscator regex (#5266)

---
 .../Http/QueryStringObfuscation/Obfuscator.cs    | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/tracer/src/Datadog.Trace/Util/Http/QueryStringObfuscation/Obfuscator.cs b/tracer/src/Datadog.Trace/Util/Http/QueryStringObfuscation/Obfuscator.cs
index e57a6929ae81..3e3e1b55c1fd 100644
--- a/tracer/src/Datadog.Trace/Util/Http/QueryStringObfuscation/Obfuscator.cs
+++ b/tracer/src/Datadog.Trace/Util/Http/QueryStringObfuscation/Obfuscator.cs
@@ -1,11 +1,8 @@
-// <copyright file="Obfuscator.cs" company="Datadog">
+// <copyright file="Obfuscator.cs" company="Datadog">
 // Unless explicitly stated otherwise all files in this repository are licensed under the Apache 2 License.
 // This product includes software developed at Datadog (https://www.datadoghq.com/). Copyright 2017 Datadog, Inc.
 // </copyright>
 
-// turns out strict formatting and optional compilation don't like each other
-#pragma warning disable SA1001, SA1116, SA1118
-
 using System;
 using System.Text.RegularExpressions;
 using Datadog.Trace.Logging;
@@ -29,6 +26,17 @@ internal Obfuscator(string pattern, TimeSpan timeout, IDatadogLogger logger)
                                          RegexOptions.IgnorePatternWhitespace;
 
             _regex = new Regex(pattern, options, _timeout);
+
+            try
+            {
+                // Warmup the regex
+                // Can't use empty string, space, or dot, as they are optimized and don't actually trigger the compilation
+                _ = _regex.Match("o");
+            }
+            catch
+            {
+                // Nothing to log here
+            }
         }
 
         /// <summary>