open-telemetry#172 Resource detectors for Docker

- Added Resource detectors for Docker environment to extract container.id
- Added Unit Tests

opentelemetry-dotnet-contrib.sln

@@ -156,6 +156,10 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Examples.Owin", "examples\o
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "OpenTelemetry.Contrib.Instrumentation.Owin.Tests", "test\OpenTelemetry.Contrib.Instrumentation.Owin.Tests\OpenTelemetry.Contrib.Instrumentation.Owin.Tests.csproj", "{D52558C8-B7BF-4F59-A0FA-9AA629E68012}"
 EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenTelemetry.Contrib.Extensions.Docker", "src\OpenTelemetry.Contrib.Extensions.Docker\OpenTelemetry.Contrib.Extensions.Docker.csproj", "{498A6808-C0DF-441F-A764-51A3BC4B8FC5}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "OpenTelemetry.Contrib.Extensions.Docker.Tests", "test\OpenTelemetry.Contrib.Extensions.Docker.Tests\OpenTelemetry.Contrib.Extensions.Docker.Tests.csproj", "{FB41E19E-2682-4D07-BA59-FD5205AFA71E}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -306,6 +310,14 @@ Global
 		{D52558C8-B7BF-4F59-A0FA-9AA629E68012}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{D52558C8-B7BF-4F59-A0FA-9AA629E68012}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{D52558C8-B7BF-4F59-A0FA-9AA629E68012}.Release|Any CPU.Build.0 = Release|Any CPU
+		{498A6808-C0DF-441F-A764-51A3BC4B8FC5}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{498A6808-C0DF-441F-A764-51A3BC4B8FC5}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{498A6808-C0DF-441F-A764-51A3BC4B8FC5}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{498A6808-C0DF-441F-A764-51A3BC4B8FC5}.Release|Any CPU.Build.0 = Release|Any CPU
+		{FB41E19E-2682-4D07-BA59-FD5205AFA71E}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{FB41E19E-2682-4D07-BA59-FD5205AFA71E}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{FB41E19E-2682-4D07-BA59-FD5205AFA71E}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{FB41E19E-2682-4D07-BA59-FD5205AFA71E}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
@@ -353,6 +365,8 @@ Global
 		{8D11A34C-D0EF-4DE1-8230-32168E67044D} = {B75EE478-97F7-4E9F-9A5A-DB3D0988EDEA}
 		{6B3AA3F2-89A7-433F-918A-1E5E6AAF8423} = {8D11A34C-D0EF-4DE1-8230-32168E67044D}
 		{D52558C8-B7BF-4F59-A0FA-9AA629E68012} = {2097345F-4DD3-477D-BC54-A922F9B2B402}
+		{498A6808-C0DF-441F-A764-51A3BC4B8FC5} = {22DF5DC0-1290-4E83-A9D8-6BB7DE3B3E63}
+		{FB41E19E-2682-4D07-BA59-FD5205AFA71E} = {2097345F-4DD3-477D-BC54-A922F9B2B402}
 	EndGlobalSection
 	GlobalSection(ExtensibilityGlobals) = postSolution
 		SolutionGuid = {B0816796-CDB3-47D7-8C3C-946434DE3B66}

src/OpenTelemetry.Contrib.Extensions.Docker/AssemblyInfo.cs

@@ -0,0 +1,23 @@
+// <copyright file="AssemblyInfo.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Runtime.CompilerServices;
+
+#if SIGNED
+[assembly: InternalsVisibleTo("OpenTelemetry.Contrib.Extensions.Docker.Tests, PublicKey=002400000480000094000000060200000024000052534131000400000100010051c1562a090fb0c9f391012a32198b5e5d9a60e9b80fa2d7b434c9e5ccb7259bd606e66f9660676afc6692b8cdc6793d190904551d2103b7b22fa636dcbb8208839785ba402ea08fc00c8f1500ccef28bbf599aa64ffb1e1d5dc1bf3420a3777badfe697856e9d52070a50c3ea5821c80bef17ca3acffa28f89dd413f096f898")]
+#else
+[assembly: InternalsVisibleTo("OpenTelemetry.Contrib.Extensions.Docker.Tests")]
+#endif

src/OpenTelemetry.Contrib.Extensions.Docker/DockerEventSource.cs

@@ -0,0 +1,63 @@
+// <copyright file="DockerEventSource.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System;
+using System.Diagnostics.Tracing;
+using System.Globalization;
+using System.Threading;
+
+namespace OpenTelemetry.Contrib.Extensions.Docker
+{
+    [EventSource(Name = "OpenTelemetry-Docker")]
+    internal class DockerEventSource : EventSource
+    {
+        public static DockerEventSource Log = new DockerEventSource();
+
+        [NonEvent]
+        public void ResourceAttributesExtractException(string format, Exception ex)
+        {
+            if (this.IsEnabled(EventLevel.Warning, (EventKeywords)(-1)))
+            {
+                this.FailedToExtractResourceAttributes(format, ToInvariantString(ex));
+            }
+        }
+
+        [Event(3, Message = "Failed to extract resource attributes in '{0}'.", Level = EventLevel.Warning)]
+        public void FailedToExtractResourceAttributes(string format, string exception)
+        {
+            this.WriteEvent(3, format, exception);
+        }
+
+        /// <summary>
+        /// Returns a culture-independent string representation of the given <paramref name="exception"/> object,
+        /// appropriate for diagnostics tracing.
+        /// </summary>
+        private static string ToInvariantString(Exception exception)
+        {
+            var originalUICulture = Thread.CurrentThread.CurrentUICulture;
+
+            try
+            {
+                Thread.CurrentThread.CurrentUICulture = CultureInfo.InvariantCulture;
+                return exception.ToString();
+            }
+            finally
+            {
+                Thread.CurrentThread.CurrentUICulture = originalUICulture;
+            }
+        }
+    }
+}

src/OpenTelemetry.Contrib.Extensions.Docker/OpenTelemetry.Contrib.Extensions.Docker.csproj

@@ -0,0 +1,9 @@
+<Project Sdk="Microsoft.NET.Sdk">
+  <PropertyGroup>
+    <TargetFrameworks>net452;netstandard2.0</TargetFrameworks>
+    <Description>OpenTelemetry extensions for Docker</Description>
+  </PropertyGroup>
+  <ItemGroup>
+    <PackageReference Include="OpenTelemetry" Version="1.1.0" />
+  </ItemGroup>
+</Project>

src/OpenTelemetry.Contrib.Extensions.Docker/README.md

@@ -0,0 +1,26 @@
+
+### Docker Resource Detectors
+
+You can configure Docker resource detector to 
+the `TracerProvider` with the following example below.
+
+```csharp
+using OpenTelemetry;
+using OpenTelemetry.Contrib.Extensions.Docker;
+
+var tracerProvider = Sdk.CreateTracerProviderBuilder()
+                        // other configurations
+                        .SetResourceBuilder(ResourceBuilder
+                            .CreateDefault()
+                            .AddDockerDetector())
+                        .Build();
+```
+
+The resource detectors will record the following metadata based on where
+your application is running:
+
+- **DockerResourceDetector**: container id.
+
+## References
+
+- [OpenTelemetry Project](https://opentelemetry.io/)

src/OpenTelemetry.Contrib.Extensions.Docker/Resources/DockerResourceDetector.cs

@@ -0,0 +1,133 @@
+// <copyright file="DockerResourceDetector.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System;
+using System.Collections.Generic;
+using System.IO;
+using OpenTelemetry.Contrib.Extensions.Docker.Utils;
+
+namespace OpenTelemetry.Contrib.Extensions.Docker.Resources
+{
+    /// <summary>
+    /// Resource detector for application running in Docker environment.
+    /// </summary>
+    public class DockerResourceDetector : IResourceDetector
+    {
+        private const string FILEPATH = "/proc/self/cgroup";
+
+        /// <summary>
+        /// Detects the resource attributes from Docker.
+        /// </summary>
+        /// <returns>List of key-value pairs of resource attributes.</returns>
+        public IEnumerable<KeyValuePair<string, object>> Detect()
+        {
+            string containerId = this.ExtractContainerId(FILEPATH);
+
+            if (string.IsNullOrEmpty(containerId))
+            {
+                return null;
+            }
+
+            return this.BuildResourceAttributes(containerId);
+        }
+
+        /// <summary>
+        /// Builds the resource attributes from Container Id.
+        /// </summary>
+        /// <param name="containerId">Container Id</param>
+        /// <returns>List of key-value pairs of resource attributes.</returns>
+        internal List<KeyValuePair<string, object>> BuildResourceAttributes(string containerId)
+        {
+            var resourceAttributes = new List<KeyValuePair<string, object>>()
+            {
+                new KeyValuePair<string, object>(DockerSemanticConventions.AttributeContainerID, containerId),
+            };
+
+            return resourceAttributes;
+        }
+
+        /// <summary>
+        /// Extracts Container Id from path.
+        /// </summary>
+        /// <param name="path">cgroup path.</param>
+        /// <returns>Container Id, Null if not found or exception being thrown.</returns>
+        internal string ExtractContainerId(string path)
+        {
+            try
+            {
+                if (!File.Exists(path))
+                {
+                    return null;
+                }
+
+                foreach (string line in File.ReadLines(path))
+                {
+                    string containerId = (!string.IsNullOrEmpty(line)) ? this.GetIdFromLine(line) : null;
+                    if (!string.IsNullOrEmpty(containerId))
+                    {
+                        return containerId;
+                    }
+                }
+            }
+            catch (Exception ex)
+            {
+                DockerEventSource.Log.ResourceAttributesExtractException($"{nameof(DockerResourceDetector)} : Failed to extract Container id from path", ex);
+            }
+
+            return null;
+        }
+
+        /// <summary>
+        /// Gets the Container Id from the line after removing the prefix and suffix.
+        /// </summary>
+        /// <param name="line">line read from cgroup file.</param>
+        /// <returns>Container Id.</returns>
+        internal string GetIdFromLine(string line)
+        {
+            // This cgroup output line should have the container id in it
+            int lastSlashIndex = line.LastIndexOf('/');
+            if (lastSlashIndex < 0)
+            {
+                return null;
+            }
+
+            string lastSection = line.Substring(lastSlashIndex + 1);
+            int startIndex = lastSection.LastIndexOf('-');
+            int endIndex = lastSection.LastIndexOf('.');
+
+            string containerId = this.RemovePrefixAndSuffixIfneeded(lastSection, startIndex, endIndex);
+
+            if (string.IsNullOrEmpty(containerId) || !EncodingUtils.IsValidHexString(containerId))
+            {
+                return null;
+            }
+
+            return containerId;
+        }
+
+        private string RemovePrefixAndSuffixIfneeded(string input, int startIndex, int endIndex)
+        {
+            startIndex = (startIndex == -1) ? 0 : startIndex + 1;
+
+            if (endIndex == -1)
+            {
+                endIndex = input.Length;
+            }
+
+            return input.Substring(startIndex, endIndex - startIndex);
+        }
+    }
+}

src/OpenTelemetry.Contrib.Extensions.Docker/Resources/DockerSemanticConventions.cs

@@ -0,0 +1,23 @@
+// <copyright file="DockerSemanticConventions.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+namespace OpenTelemetry.Contrib.Extensions.Docker.Resources
+{
+    internal static class DockerSemanticConventions
+    {
+        public const string AttributeContainerID = "container.id";
+    }
+}

src/OpenTelemetry.Contrib.Extensions.Docker/Resources/IResourceDetector.cs

@@ -0,0 +1,33 @@
+// <copyright file="IResourceDetector.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System.Collections.Generic;
+
+namespace OpenTelemetry.Contrib.Extensions.Docker.Resources
+{
+    /// <summary>
+    /// Resource detector interface.
+    /// Mocking https://github.com/open-telemetry/opentelemetry-dotnet/blob/6b7f2dd77cf9d37260a853fcc95f7b77e296065d/src/OpenTelemetry/Resources/IResourceDetector.cs.
+    /// </summary>
+    public interface IResourceDetector
+    {
+        /// <summary>
+        /// Called to get key-value pairs of attribute from detector.
+        /// </summary>
+        /// <returns>List of key-value pairs of resource attributes.</returns>
+        IEnumerable<KeyValuePair<string, object>> Detect();
+    }
+}

src/OpenTelemetry.Contrib.Extensions.Docker/Resources/ResourceBuilderExtensions.cs

@@ -0,0 +1,45 @@
+// <copyright file="ResourceBuilderExtensions.cs" company="OpenTelemetry Authors">
+// Copyright The OpenTelemetry Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+// </copyright>
+
+using System;
+using OpenTelemetry.Contrib.Extensions.Docker.Resources;
+
+namespace OpenTelemetry.Resources
+{
+    /// <summary>
+    /// Extension class for ResourceBuilder.
+    /// </summary>
+    public static class ResourceBuilderExtensions
+    {
+        /// <summary>
+        /// Add Docker resource detector to ResourceBuilder.
+        /// </summary>
+        /// <param name="resourceBuilder"><see cref="ResourceBuilder"/> being configured.</param>
+        /// <returns>The instance of <see cref="ResourceBuilder"/> to chain the calls.</returns>
+        public static ResourceBuilder AddDockerDetector(this ResourceBuilder resourceBuilder)
+        {
+            var resourceDetector = new DockerResourceDetector();
+            var resourceAttributes = resourceDetector.Detect();
+
+            if (resourceAttributes != null)
+            {
+                resourceBuilder.AddAttributes(resourceAttributes);
+            }
+
+            return resourceBuilder;
+        }
+    }
+}