OpenTelemetry .NET Automatic Instrumentation

This project adds OpenTelemetry instrumentation to .NET applications without having to modify their source code.

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Warning The following documentation refers to the in-development version of OpenTelemetry .NET Automatic Instrumentation. Docs for the latest version (1.0.2) can be found in opentelemetry.io or here.

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Quick start

If you'd like to try the instrumentation on an existing application before learning more about the configuration options and the project, follow the instructions at Using the OpenTelemetry.AutoInstrumentation NuGet packages or use the appropriate install script:

• On Linux and macOS, use the shell scripts.
• On Windows, use the PowerShell module.

To see the telemetry from your application directly on the standard output, set the following environment variables to true before launching your application:

• OTEL_DOTNET_AUTO_LOGS_CONSOLE_EXPORTER_ENABLED
• OTEL_DOTNET_AUTO_METRICS_CONSOLE_EXPORTER_ENABLED
• OTEL_DOTNET_AUTO_TRACES_CONSOLE_EXPORTER_ENABLED

For a demo using docker compose, clone this repository and follow the examples/demo/README.md.

Components

OpenTelemetry .NET Automatic Instrumentation is built on top of OpenTelemetry .NET:

• Core components: 1.6.0
• System.Diagnostics.DiagnosticSource: 7.0.2 referencing System.Runtime.CompilerServices.Unsafe: 6.0.0

You can find all references in OpenTelemetry.AutoInstrumentation.csproj and OpenTelemetry.AutoInstrumentation.AdditionalDeps/Directory.Build.props.

To automatically instrument applications, the OpenTelemetry .NET Automatic Instrumentation does the following:

1. Injects and configures the OpenTelemetry .NET SDK into the application.
2. Adds OpenTelemetry Instrumentation to key packages and APIs used by the application.

You can enable the OpenTelemetry .NET Automatic Instrumentation as a .NET Profiler to inject additional instrumentations of this project at runtime, using a technique known as monkey-patching. When enabled, the OpenTelemetry .NET Automatic Instrumentation generates traces for libraries that don't already generate traces using the OpenTelemetry .NET SDK.

See design.md for an architectural overview.

Status

The versioning information and stability guarantees can be found in the versioning documentation.

Compatibility

OpenTelemetry .NET Automatic Instrumentation attempts to work with all officially supported operating systems and versions of .NET.

The minimal supported version of .NET Framework is 4.6.2.

CI tests run against the following operating systems:

• Alpine
• CentOS 7
• macOS Big Sur 11
• Microsoft Windows Server 2022
• Ubuntu 20.04 LTS

Instrumented libraries and frameworks

See config.md#instrumented-libraries-and-frameworks.

Get started

Note ARM architectures are not supported yet, see #2181.

Considerations on scope

Instrumenting self-contained applications is supported through NuGet packages. Note that a self-contained application is automatically generated in .NET 7.0 whenever the dotnet publish or dotnet build command is used with a Runtime Identifier (RID) parameter, for example when -r or --runtime is used when running the command.

Until version v0.6.0-beta.1 (inclusive) there were issues instrumenting the dotnet CLI. To build and launch an instrumented application, take the following into account if you are using one of the affected versions:

• Don't set the automatic instrumentation environment variables in the same session used to run the dotnet tool.
• Don't launch the application to be instrumented using dotnet run or dotnet <dll>. Build the application in an isolated shell, without the automatic instrumentation environment variables set, and use a separate session with the automatic instrumentation variables to directly launch the executable.

Install

Download and extract the appropriate binaries from the latest release.

Note The path where you put the binaries is referenced as $INSTALL_DIR

Instrument a .NET application

When running your application, make sure to:

1. Set the resources.
2. Set the environment variables from the table below.

Environment variable	.NET version	Value
COR_ENABLE_PROFILING	.NET Framework	1
COR_PROFILER	.NET Framework	{918728DD-259F-4A6A-AC2B-B85E1B658318}
COR_PROFILER_PATH_32	.NET Framework	$INSTALL_DIR/win-x86/OpenTelemetry.AutoInstrumentation.Native.dll
COR_PROFILER_PATH_64	.NET Framework	$INSTALL_DIR/win-x64/OpenTelemetry.AutoInstrumentation.Native.dll
CORECLR_ENABLE_PROFILING	.NET	1
CORECLR_PROFILER	.NET	{918728DD-259F-4A6A-AC2B-B85E1B658318}
CORECLR_PROFILER_PATH	.NET on Linux glibc	$INSTALL_DIR/linux-x64/OpenTelemetry.AutoInstrumentation.Native.so
CORECLR_PROFILER_PATH	.NET on Linux musl	$INSTALL_DIR/linux-musl-x64/OpenTelemetry.AutoInstrumentation.Native.so
CORECLR_PROFILER_PATH	.NET on macOS	$INSTALL_DIR/osx-x64/OpenTelemetry.AutoInstrumentation.Native.dylib
CORECLR_PROFILER_PATH_32	.NET on Windows	$INSTALL_DIR/win-x86/OpenTelemetry.AutoInstrumentation.Native.dll
CORECLR_PROFILER_PATH_64	.NET on Windows	$INSTALL_DIR/win-x64/OpenTelemetry.AutoInstrumentation.Native.dll
DOTNET_ADDITIONAL_DEPS	.NET	$INSTALL_DIR/AdditionalDeps
DOTNET_SHARED_STORE	.NET	$INSTALL_DIR/store
DOTNET_STARTUP_HOOKS	.NET	$INSTALL_DIR/net/OpenTelemetry.AutoInstrumentation.StartupHook.dll
OTEL_DOTNET_AUTO_HOME	All versions	$INSTALL_DIR

Note Some settings can be omitted on .NET. For more information, see config.md.

Shell scripts

You can install OpenTelemetry .NET Automatic Instrumentation and instrument your .NET application using the provided Shell scripts.

Note On macOS coreutils is required.

Example usage:

# Download the bash script
curl -sSfL https://raw.githubusercontent.com/open-telemetry/opentelemetry-dotnet-instrumentation/v1.0.2/otel-dotnet-auto-install.sh -O

# Install core files
sh ./otel-dotnet-auto-install.sh

# Enable execution for the instrumentation script
chmod +x $HOME/.otel-dotnet-auto/instrument.sh

# Setup the instrumentation for the current shell session
. $HOME/.otel-dotnet-auto/instrument.sh

# Run your application with instrumentation
OTEL_SERVICE_NAME=myapp OTEL_RESOURCE_ATTRIBUTES=deployment.environment=staging,service.version=1.0.0 ./MyNetApp

otel-dotnet-auto-install.sh script uses environment variables as parameters:

Parameter	Description	Required	Default value
OTEL_DOTNET_AUTO_HOME	Location where binaries are to be installed	No	$HOME/.otel-dotnet-auto
OS_TYPE	Possible values: linux-glibc, linux-musl, macos, windows	No	Calculated
TMPDIR	Temporary directory used when downloading the files	No	$(mktemp -d)
VERSION	Version to download	No	1.0.2

instrument.sh script uses environment variables as parameters:

Parameter	Description	Required	Default value
ENABLE_PROFILING	Whether to set the .NET CLR Profiler, possible values: true, false	No	true
OTEL_DOTNET_AUTO_HOME	Location where binaries are to be installed	No	$HOME/.otel-dotnet-auto
OS_TYPE	Possible values: linux-glibc, linux-musl, macos, windows	No	Calculated

PowerShell module (Windows)

On Windows, you should install OpenTelemetry .NET Automatic Instrumentation and instrument your .NET application using the provided PowerShell module. Example usage (run as administrator):

# Download the module
$module_url = "https://raw.githubusercontent.com/open-telemetry/opentelemetry-dotnet-instrumentation/v1.0.2/OpenTelemetry.DotNet.Auto.psm1"
$download_path = Join-Path $env:temp "OpenTelemetry.DotNet.Auto.psm1"
Invoke-WebRequest -Uri $module_url -OutFile $download_path -UseBasicParsing

# Import the module to use its functions
Import-Module $download_path

# Install core files (online vs offline method)
Install-OpenTelemetryCore
Install-OpenTelemetryCore -LocalPath "C:\Path\To\OpenTelemetry.zip" 

# Set up the instrumentation for the current PowerShell session
Register-OpenTelemetryForCurrentSession -OTelServiceName "MyServiceDisplayName"

# Run your application with instrumentation
.\MyNetApp.exe

You can get usage information by calling:

# List all available commands
Get-Command -Module OpenTelemetry.DotNet.Auto

# Get command's usage information
Get-Help Install-OpenTelemetryCore -Detailed

Warning The PowerShell module works only on PowerShell 5.1 which is the one installed by default on Windows.

Instrument a container

You can find our demonstrative example that uses Docker Compose here.

You can also consider using the Kubernetes Operator for OpenTelemetry Collector.

Instrument a Windows Service running a .NET application

See windows-service-instrumentation.md.

Instrument an ASP.NET application deployed on IIS

See iis-instrumentation.md.

Configuration

See config.md.

Manual instrumentation

See manual-instrumentation.md.

Log to trace correlation

See log-trace-correlation.md.

Troubleshooting

See troubleshooting.md.

Contact

See CONTRIBUTING.md.

Contributing

See CONTRIBUTING.md.

Community Roles

Maintainers (@open-telemetry/dotnet-instrumentation-maintainers):

• Chris Ventura, New Relic
• Paulo Janotti, Splunk
• Piotr Kiełkowicz, Splunk
• Rajkumar Rangaraj, Microsoft
• Robert Pająk, Splunk
• Zach Montoya, Datadog

Approvers (@open-telemetry/dotnet-instrumentation-approvers):

• Rasmus Kuusmann, Splunk

Emeritus Maintainer/Approver/Triager:

• Colin Higgins
• Greg Paperin
• Kevin Gosse
• Lucas Pimentel-Ordyna
• Mike Goldsmith
• Tony Redondo

Learn more about roles in the community repository.