Relax ECS container ID regex (#2430)

As agreed in the weekly team call, we will relax the ECS container ID
regex in the spec since we have seen examples where the container ID
suffix is shorter than the documented ten characters.

Author: stevejgordon

CHANGELOG.asciidoc

@@ -23,6 +23,13 @@ endif::[]
 [[release-notes-1.x]]
 === .NET Agent version 1.x
 
+[[release-notes-1.28.5]]
+==== 1.28.5 - 2024/08/28
+
+===== Bug fixes
+
+{pull}2430[#2430] Relax ECS container ID regex.
+
 [[release-notes-1.28.4]]
 ==== 1.28.4 - 2024/08/19
 

src/Elastic.Apm/Helpers/SystemInfoHelper.cs

@@ -18,7 +18,7 @@ internal class SystemInfoHelper
 	{
 		private readonly Regex _containerUidRegex = new Regex("^[0-9a-fA-F]{64}$");
 		private readonly Regex _shortenedUuidRegex = new Regex("^[0-9a-fA-F]{8}\\-[0-9a-fA-F]{4}\\-[0-9a-fA-F]{4}\\-[0-9a-fA-F]{4}\\-[0-9a-fA-F]{4,}");
-		private readonly Regex _ecsContainerIdRegex = new Regex("^[a-z0-9]{32}-[0-9]{10}$");
+		private readonly Regex _ecsContainerIdRegex = new Regex("^[a-z0-9]{32}-[0-9]{1,10}$");
 		private readonly Regex _podRegex = new Regex(
 			@"(?:^/kubepods[\S]*/pod([^/]+)$)|(?:^/kubepods\.slice/(kubepods-[^/]+\.slice/)?kubepods[^/]*-pod([^/]+)\.slice$)");