[skip ci] fix: update process discovery FFI

Author: dmehala

tracer/src/Datadog.Trace/LibDatadog/NativeInterop.cs

@@ -116,16 +116,17 @@ internal static class Common
 
     internal static class LibraryConfig
     {
-        [DllImport(DllName, EntryPoint = "ddog_store_tracer_metadata")]
-        internal static extern TracerMemfdHandleResult StoreTracerMetadata(
-            byte schemaVersion,
-            CharSlice runtimeId,
-            CharSlice tracerLanguage,
-            CharSlice tracerVersion,
-            CharSlice hostname,
-            CharSlice serviceName,
-            CharSlice serviceEnv,
-            CharSlice serviceVersion);
+        [DllImport(DllName, EntryPoint = "ddog_tracer_metadata_new")]
+        internal static extern IntPtr TracerMetadataNew();
+
+        [DllImport(DllName, EntryPoint = "ddog_tracer_metadata_free")]
+        internal static extern void TracerMetadataFree(IntPtr metadata);
+
+        [DllImport(DllName, EntryPoint = "ddog_tracer_metadata_set")]
+        internal static extern void TracerMetadataSet(IntPtr metadata, MetadataKind kind, CString value);
+
+        [DllImport(DllName, EntryPoint = "ddog_tracer_metadata_store")]
+        internal static extern TracerMemfdHandleResult StoreTracerMetadata(IntPtr metadata);
 
         [DllImport(DllName, EntryPoint = "ddog_library_configurator_new")]
         internal static extern IntPtr ConfiguratorNew(byte debugLogs, CharSlice language);

tracer/src/Datadog.Trace/LibDatadog/ServiceDiscovery/MetadataKind.cs

@@ -0,0 +1,22 @@
+// <copyright file="MetadataKind.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>
+
+#nullable enable
+using System;
+
+namespace Datadog.Trace.LibDatadog.ServiceDiscovery;
+
+internal enum MetadataKind : int
+{
+    RuntimeId = 0,
+    TracerLanguage = 1,
+    TracerVersion = 2,
+    Hostname = 3,
+    ServiceName = 4,
+    ServiceEnvironment = 5,
+    ServiceVersion = 6,
+    ProcessTags = 7,
+    ContainerId = 8,
+}

tracer/src/Datadog.Trace/LibDatadog/ServiceDiscovery/ServiceDiscoveryHelper.cs

@@ -31,7 +31,6 @@ internal static StoreMetadataResult StoreTracerMetadata(TracerSettings tracerSet
             try
             {
                 var result = StoreTracerMetadata(
-                    1,
                     Tracer.RuntimeId,
                     TracerConstants.Language,
                     TracerConstants.ThreePartVersion,
@@ -66,7 +65,6 @@ internal static StoreMetadataResult StoreTracerMetadata(TracerSettings tracerSet
     }
 
     private static TracerMemfdHandleResult StoreTracerMetadata(
-        byte schemaVersion,
         string runtimeId,
         string tracerLanguage,
         string tracerVersion,
@@ -75,14 +73,32 @@ private static TracerMemfdHandleResult StoreTracerMetadata(
         string? serviceEnv,
         string? serviceVersion)
     {
-        using var runtimeIdCharSlice = new CharSlice(runtimeId);
-        using var tracerLanguageCharSlice = new CharSlice(tracerLanguage);
-        using var tracerVersionCharSlice = new CharSlice(tracerVersion);
-        using var hostnameCharSlice = new CharSlice(hostname);
-        using var serviceNameCharSlice = new CharSlice(serviceName);
-        using var serviceEnvCharSlice = new CharSlice(serviceEnv);
-        using var serviceVersionCharSlice = new CharSlice(serviceVersion);
+        IntPtr ptr = IntPtr.Zero;
+        try
+        {
+            ptr = NativeInterop.LibraryConfig.TracerMetadataNew();
+            SetMetadata(ptr, MetadataKind.RuntimeId, runtimeId);
+            SetMetadata(ptr, MetadataKind.TracerLanguage, tracerLanguage);
+            SetMetadata(ptr, MetadataKind.TracerVersion, tracerVersion);
+            SetMetadata(ptr, MetadataKind.Hostname, hostname);
+            SetMetadata(ptr, MetadataKind.ServiceName, serviceName);
+            SetMetadata(ptr, MetadataKind.ServiceEnvironment, serviceEnv);
+            SetMetadata(ptr, MetadataKind.ServiceVersion, serviceVersion);
 
-        return NativeInterop.LibraryConfig.StoreTracerMetadata(schemaVersion, runtimeIdCharSlice, tracerLanguageCharSlice, tracerVersionCharSlice, hostnameCharSlice, serviceNameCharSlice, serviceEnvCharSlice, serviceVersionCharSlice);
+            return NativeInterop.LibraryConfig.StoreTracerMetadata(ptr);
+        }
+        finally
+        {
+            if (ptr != IntPtr.Zero)
+            {
+                NativeInterop.LibraryConfig.TracerMetadataFree(ptr);
+            }
+        }
+
+        void SetMetadata(IntPtr ptr, MetadataKind kind, string? value)
+        {
+            using var valueCharSlice = new CString(value);
+            NativeInterop.LibraryConfig.TracerMetadataSet(ptr, kind, valueCharSlice);
+        }
     }
 }