update-json-specs.yml: add container_metadata_discovery.json (#2156)

Co-authored-by: Martijn Laarman <[email protected]>

src/Elastic.Apm/Helpers/SystemInfoHelper.cs

@@ -5,6 +5,7 @@
 using System;
 using System.Data.Common;
 using System.IO;
+using System.Linq;
 using System.Net;
 using System.Net.NetworkInformation;
 using System.Text.RegularExpressions;
@@ -28,6 +29,28 @@ internal class SystemInfoHelper
 		public SystemInfoHelper(IApmLogger logger)
 			=> _logger = logger.Scoped(nameof(SystemInfoHelper));
 
+
+		//3997 3984 253:1 /var/lib/docker/containers/6548c6863fb748e72d1e2a4f824fde92f720952d062dede1318c2d6219a672d6/hostname /etc/hostname rw,relatime shared:1877 - ext4 /dev/mapper/vgubuntu-root rw,errors=remount-ro
+		internal void ParseMountInfo(Api.System system, string reportedHostName, string line)
+		{
+
+			var fields = line.Split(' ');
+			if (fields.Length <= 3)
+				return;
+
+			var path = fields[3];
+			foreach (var folder in path.Split('/'))
+			{
+				//naive implementation to check for guid.
+				if (folder.Length != 64)
+					continue;
+				system.Container = new Container { Id = folder };
+			}
+
+		}
+
+		// "1:name=systemd:/ecs/03752a671e744971a862edcee6195646/03752a671e744971a862edcee6195646-4015103728"
+		// "0::/kubepods.slice/kubepods-burstable.slice/kubepods-burstable-pod121157b5_c67d_4c3e_9052_cb27bbb711fb.slice/cri-containerd-1cd3449e930b8a28c7595240fa32ba20c84f36d059e5fbe63104ad40057992d1.scope"
 		internal void ParseContainerId(Api.System system, string reportedHostName, string line)
 		{
 			var fields = line.Split(':');
@@ -43,11 +66,13 @@ internal void ParseContainerId(Api.System system, string reportedHostName, strin
 			if (string.IsNullOrWhiteSpace(idPart))
 				return;
 
-			// Legacy, e.g.: /system.slice/docker-<CID>.scope
+			// Legacy, e.g.: /system.slice/docker-<CID>.scope or cri-containerd-<CID>.scope
 			if (idPart.EndsWith(".scope"))
 			{
-				idPart = idPart.Substring(0, idPart.Length - ".scope".Length)
-					.Substring(idPart.IndexOf("-", StringComparison.Ordinal) + 1);
+				var idParts = idPart.Split(new[] { '-' }, StringSplitOptions.RemoveEmptyEntries);
+				var containerIdWithScope = idParts.Last();
+
+				idPart = containerIdWithScope.Substring(0, containerIdWithScope.Length - ".scope".Length);
 			}
 
 			// Looking for kubernetes info
@@ -173,8 +198,10 @@ static string NormalizeHostName(string hostName) =>
 
 		private void ParseContainerInfo(Api.System system, string reportedHostName)
 		{
+			//0::/
 			try
 			{
+				var fallBackToMountInfo = false;
 				using var sr = GetCGroupAsStream();
 				if (sr is null)
 				{
@@ -183,12 +210,34 @@ private void ParseContainerInfo(Api.System system, string reportedHostName)
 					return;
 				}
 
+				var i = 0;
 				string line;
 				while ((line = sr.ReadLine()) != null)
 				{
+					if (line == "0::/" && i == 0)
+						fallBackToMountInfo = true;
 					ParseContainerId(system, reportedHostName, line);
 					if (system.Container != null)
 						return;
+					i++;
+				}
+				if (!fallBackToMountInfo)
+					return;
+
+				using var mi = GetMountInfoAsStream();
+				if (mi is null)
+				{
+					_logger.Debug()?.Log("No /proc/self/mountinfo found - no information to fallback to");
+					return;
+				}
+
+				while ((line = mi.ReadLine()) != null)
+				{
+					if (!line.Contains("/etc/hostname"))
+						continue;
+					ParseMountInfo(system, reportedHostName, line);
+					if (system.Container != null)
+						return;
 				}
 			}
 			catch (Exception e)
@@ -201,8 +250,12 @@ private void ParseContainerInfo(Api.System system, string reportedHostName)
 					"Failed parsing container id - the agent will not report container id. Likely the application is not running within a container");
 		}
 
-		protected virtual StreamReader GetCGroupAsStream()
-			=> File.Exists("/proc/self/cgroup") ? new StreamReader("/proc/self/cgroup") : null;
+		protected virtual StreamReader GetCGroupAsStream() =>
+			File.Exists("/proc/self/cgroup") ? new StreamReader("/proc/self/cgroup") : null;
+
+		protected virtual StreamReader GetMountInfoAsStream() =>
+			File.Exists("/proc/self/mountinfo") ? new StreamReader("/proc/self/mountinfo") : null;
+
 
 		internal const string Namespace = "KUBERNETES_NAMESPACE";
 		internal const string PodName = "KUBERNETES_POD_NAME";

test/Elastic.Apm.Tests.Utilities/CGroupTestCasesAttribute.cs

@@ -0,0 +1,78 @@
+// Licensed to Elasticsearch B.V under
+// one or more agreements.
+// Elasticsearch B.V licenses this file to you under the Apache 2.0 License.
+// See the LICENSE file in the project root for more information
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using System.Linq;
+using System.Reflection;
+using Elastic.Apm.Libraries.Newtonsoft.Json.Linq;
+using Xunit.Sdk;
+
+namespace Elastic.Apm.Tests.Utilities;
+
+public struct CgroupFiles
+{
+	public string ProcSelfCgroup;
+	public string[] MountInfo;
+}
+
+public struct CGroupTestData
+{
+	public CgroupFiles Files;
+	public string ContainerId;
+	public string PodId;
+}
+
+
+public class CGroupTestCasesAttribute : DataAttribute
+{
+	private readonly string _fileName = "./TestResources/json-specs//container_metadata_discovery.json";
+
+	public override IEnumerable<object[]> GetData(MethodInfo testMethod)
+	{
+		if (!File.Exists(_fileName))
+			throw new ArgumentException($"JSON input file {_fileName} does not exist");
+
+		var jToken = JToken.Parse(File.ReadAllText(_fileName), new JsonLoadSettings
+		{
+			CommentHandling = CommentHandling.Ignore
+		});
+
+		foreach (var kvp in (JObject)jToken)
+		{
+			var name = kvp.Key;
+			var data = ParseTestData(kvp.Value as JObject);
+			yield return [name, data];
+		}
+	}
+
+	private static CGroupTestData ParseTestData(JObject jToken)
+	{
+		var testData = new CGroupTestData { Files = new CgroupFiles() };
+
+		foreach (var kvp in jToken)
+		{
+			switch (kvp.Key)
+			{
+				case "containerId":
+					testData.ContainerId = kvp.Value?.Value<string>();
+					break;
+				case "podId":
+					testData.PodId = kvp.Value?.Value<string>();
+					break;
+				case "files":
+					var o = (JObject)kvp.Value;
+					var cgroupA = o.Property("/proc/self/cgroup")?.Value as JArray;
+					testData.Files.ProcSelfCgroup = cgroupA?.Values<string>().FirstOrDefault();
+
+					var mountInfoA = o.Property("/proc/self/mountinfo")?.Value as JArray;
+					testData.Files.MountInfo = mountInfoA?.Values<string>().ToArray();
+					break;
+			}
+		}
+		return testData;
+	}
+}

test/Elastic.Apm.Tests/SystemInfoHelperTests.cs

@@ -4,12 +4,14 @@
 
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using Elastic.Apm.Api.Kubernetes;
 using Elastic.Apm.Features;
 using Elastic.Apm.Helpers;
 using Elastic.Apm.Logging;
 using Elastic.Apm.Tests.Utilities;
 using FluentAssertions;
+using Newtonsoft.Json;
 using Xunit;
 
 namespace Elastic.Apm.Tests;
@@ -61,30 +63,33 @@ public void ParseKubernetesInfo_ShouldReturnNull_WhenNoEnvironmentVariablesAreSe
 		system.Kubernetes.Should().BeNull();
 	}
 
-	public struct CGroupTestData
-	{
-		public string GroupLine;
-		public string ContainerId;
-		public string PodId;
-	}
-
 	// Remove warning about unused test parameter "name"
 #pragma warning disable xUnit1026
 	[Theory]
-	[JsonFileData("./TestResources/json-specs/cgroup_parsing.json", typeof(CGroupTestData))]
+	[CGroupTestCases]
 	public void ParseKubernetesInfo_FromCGroupLine(string name, CGroupTestData data)
 	{
-		var line = data.GroupLine;
+		data.Files.ProcSelfCgroup.Should().NotBeNull();
+		var line = data.Files.ProcSelfCgroup;
 		var containerId = data.ContainerId;
 		var podId = data.PodId;
 
 		var system = new Api.System();
-		_systemInfoHelper.ParseContainerId(system, "hostname", line);
+		if (line == "0::/")
+		{
+			line = data.Files.MountInfo.FirstOrDefault(l => l.Contains("/etc/hostname"));
+			_systemInfoHelper.ParseMountInfo(system, "hostname", line);
+		}
+		else
+			_systemInfoHelper.ParseContainerId(system, "hostname", line);
 
 		if (containerId is null)
 			system.Container.Should().BeNull();
 		else
+		{
+			system.Container.Should().NotBeNull("{0}", line);
 			system.Container.Id.Should().Be(containerId);
+		}
 
 		if (podId is null)
 			system.Kubernetes.Should().BeNull();