[Exporter.Geneva] Adding user_events support for logs on Linux - user_events data transport utility

src/OpenTelemetry.Exporter.Geneva/Internal/Transports/UnixUserEventsDataTransport.cs

@@ -0,0 +1,53 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#if NET
+
+using Microsoft.LinuxTracepoints.Provider;
+
+namespace OpenTelemetry.Exporter.Geneva.Transports;
+
+internal sealed class UnixUserEventsDataTransport : IDisposable
+{
+    public const string LogsTracepointName = "geneva_logs";  // TODO: find the correct tracepoint name
+    public const string LogsTracepointNameArgs = $"{LogsTracepointName} u32 protocol;char[8] version;__rel_loc u8[] buffer";  // TODO: find the correct tracepoint args
+    public const string EventHeaderDynamicProviderName = "MicrosoftOpenTelemetryLogs";
+    public const System.Diagnostics.Tracing.EventLevel LogsTracepointEventLevel = System.Diagnostics.Tracing.EventLevel.Informational;  // TODO: find the correct event level
+    public const ulong LogsTracepointKeyword = 1;  // TODO: find the correct keyword
+
+    private readonly EventHeaderDynamicProvider eventHeaderDynamicProvider;
+
+    private UnixUserEventsDataTransport()
+    {
+        this.eventHeaderDynamicProvider = new EventHeaderDynamicProvider(EventHeaderDynamicProviderName);
+    }
+
+    public static UnixUserEventsDataTransport Instance { get; } = new();
+
+    public EventHeaderDynamicTracepoint RegisterUserEventProviderForLogs()
+    {
+        var logsTracepoint = this.eventHeaderDynamicProvider.Register(LogsTracepointEventLevel, LogsTracepointKeyword);
+        if (logsTracepoint.RegisterResult != 0)
+        {
+            // ENOENT (2): No such file or directory
+            if (logsTracepoint.RegisterResult == 2)
+            {
+                throw new NotSupportedException(
+                    $"Tracepoint registration for 'geneva_logs' failed with result: '{logsTracepoint.RegisterResult}'. Verify your distribution/kernel supports user_events: https://docs.kernel.org/trace/user_events.html.");
+            }
+
+            ExporterEventSource.Log.TransportInformation(
+                nameof(UnixUserEventsDataTransport),
+                $"Tracepoint registration operation for 'geneva_logs' returned result '{logsTracepoint.RegisterResult}' which is considered recoverable. Entering running state.");
+        }
+
+        return logsTracepoint;
+    }
+
+    public void Dispose()
+    {
+        this.eventHeaderDynamicProvider.Dispose();
+    }
+}
+
+#endif

test/OpenTelemetry.Exporter.Geneva.Tests/UnixUserEventsDataTransportTests.cs

@@ -7,12 +7,13 @@
 using System.Globalization;
 using System.Text.RegularExpressions;
 using Microsoft.LinuxTracepoints.Provider;
+using OpenTelemetry.Exporter.Geneva.Transports;
 using Xunit;
 using Xunit.Abstractions;
 
 namespace OpenTelemetry.Exporter.Geneva.Tests;
 
-[Trait("CategoryName", "Geneva:user_events:metrics")]
+[Trait("CategoryName", "Geneva:user_events")]
 public class UnixUserEventsDataTransportTests
 {
     /*
@@ -26,7 +27,7 @@ public class UnixUserEventsDataTransportTests
      *     these tests do).
      *
      *  Command:
-     *    sudo dotnet test --configuration Debug --framework net8.0 --filter CategoryName=Geneva:user_events:metrics
+     *    sudo dotnet test --configuration Debug --framework net8.0 --filter CategoryName=Geneva:user_events
      *
      * How these tests work:
      *
@@ -49,7 +50,7 @@ public UnixUserEventsDataTransportTests(ITestOutputHelper testOutputHelper)
         this.testOutputHelper = testOutputHelper;
     }
 
-    [Fact(Skip = "This would fail on Ubuntu. Skipping for now.")]
+    [Fact(Skip = "This would fail on Ubuntu. Skipping for now. See issue: #2326.")]
     public void UserEvents_Enabled_Success_Linux()
     {
         EnsureUserEventsEnabled();
@@ -113,7 +114,7 @@ public void UserEvents_Enabled_Success_Linux()
         }
     }
 
-    [Fact(Skip = "This would fail on Ubuntu. Skipping for now.")]
+    [Fact(Skip = "This would fail on Ubuntu. Skipping for now. See issue: #2326.")]
     public void UserEvents_Disabled_Success_Linux()
     {
         EnsureUserEventsEnabled();
@@ -143,6 +144,106 @@ public void UserEvents_Disabled_Success_Linux()
         }
     }
 
+    [Fact(Skip = "This would fail on Ubuntu. Skipping for now. See issue: #2326.")]
+    public void UserEvents_Logs_Success_Linux()
+    {
+        EnsureUserEventsEnabled();
+
+        var listener = new PerfTracepointListener(
+            "MicrosoftOpenTelemetryLogs_L4K1",
+            MetricUnixUserEventsDataTransport.MetricsTracepointNameArgs);
+
+        var logsTracepoint = UnixUserEventsDataTransport.Instance.RegisterUserEventProviderForLogs();
+
+        if (listener.IsEnabled())
+        {
+            throw new NotSupportedException($"{MetricUnixUserEventsDataTransport.MetricsTracepointName} is already enabled");
+        }
+
+        try
+        {
+            listener.Enable();
+
+            Console.WriteLine("------------- ready to write events -------------");
+            Thread.Sleep(5000);
+
+            if (logsTracepoint.IsEnabled)
+            {
+                var eventBuilder = CreateEventHeaderDynamicBuilder();
+
+                Console.WriteLine("About to write tracepoint:");
+                eventBuilder.Write(logsTracepoint);
+                Console.WriteLine("Written tracepoint.");
+            }
+
+            Thread.Sleep(5000);
+
+            this.testOutputHelper.WriteLine("Writing events from listener:");
+            Console.WriteLine("Writing events from listener:");
+            foreach (var e in listener.Events)
+            {
+                this.testOutputHelper.WriteLine(string.Join(", ", e.Select(kvp => $"{kvp.Key}={kvp.Value}")));
+                Console.WriteLine(string.Join(", ", e.Select(kvp => $"{kvp.Key}={kvp.Value}")));
+            }
+
+            this.testOutputHelper.WriteLine("Total events: " + listener.Events.Count);
+            Console.WriteLine("Total events: " + listener.Events.Count);
+        }
+        finally
+        {
+            try
+            {
+                listener.Disable();
+            }
+            catch
+            {
+            }
+
+            listener.Dispose();
+        }
+    }
+
+    private static EventHeaderDynamicBuilder CreateEventHeaderDynamicBuilder()
+    {
+        var eb = new EventHeaderDynamicBuilder();
+        eb.Reset("_");
+        eb.AddUInt16("__csver__", 1024, Microsoft.LinuxTracepoints.EventHeaderFieldFormat.HexInt);
+
+        eb.AddStructWithMetadataPosition("partA", out var partAFieldsCountMetadataPosition);
+
+        string rfc3339String = DateTime.UtcNow.ToUniversalTime().ToString("yyyy-MM-ddTHH:mm:ss.FFFFFFZ", CultureInfo.InvariantCulture);
+        eb.AddString16("time", rfc3339String);
+
+        byte partAFieldsCount = 1;
+
+        eb.SetStructFieldCount(partAFieldsCountMetadataPosition, partAFieldsCount);
+
+        // Part B
+
+        byte partBFieldsCount = 4; // We at least have three fields in Part B: _typeName, severityText, severityNumber, name
+        eb.AddStructWithMetadataPosition("PartB", out var partBFieldsCountMetadataPosition);
+        eb.AddString16("_typeName", "Log");
+        eb.AddUInt8("severityNumber", 21);
+
+        eb.AddString16("severityText", "Critical");
+        eb.AddString16("name", "CheckoutFailed");
+
+        eb.SetStructFieldCount(partBFieldsCountMetadataPosition, partBFieldsCount);
+
+        // Part C
+
+        byte partCFieldsCount = 0;
+        eb.AddStructWithMetadataPosition("PartC", out var partCFieldsCountMetadataPosition);
+
+        eb.AddString16("book_id", "12345");
+        eb.AddString16("book_name", "The Hitchhiker's Guide to the Galaxy");
+        partCFieldsCount += 2;
+
+        eb.SetStructFieldCount(partCFieldsCountMetadataPosition, partCFieldsCount);
+
+        return eb;
+    }
+
     private static void EnsureUserEventsEnabled()
     {
         var errors = ConsoleCommand.Run("cat", "/sys/kernel/tracing/user_events_status");
@@ -184,7 +285,7 @@ private ConsoleCommand(
                 if (!string.IsNullOrEmpty(args.Data))
                 {
                     this.output.Add(args.Data);
-                    Console.WriteLine($"[OUT] {args.Data}");
+                    Console.WriteLine($"{command} {arguments} [OUT] {args.Data}");
 
                     onOutputReceived?.Invoke(args.Data);
                 }