> For the complete documentation index, see [llms.txt](https://docs.sealights.io/knowledgebase/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sealights.io/knowledgebase/setup-and-configuration/sealights-agents-and-plugins/.net-core-agent/capturing-coverage-from-the-application/capturing-coverage-from-the-app-process.md).

# Capturing coverage from the app process

There are **two ways to capture coverage from application or service processes** with the SeaLights .NET Agent:

1. Run the process with the agent by using the **run** command.
2. Run the agent as a **background listener**.

Use the background listener flow when you cannot change the original startup command.

## Running the process with `run` <a href="#running-the-process-with-the-sealights-.net-core-agent-using-run-option" id="running-the-process-with-the-sealights-.net-core-agent-using-run-option"></a>

To capture coverage from a single application, start it through the agent.

{% tabs %}
{% tab title="PowerShell" %}
{% code overflow="wrap" lineNumbers="true" %}

```powershell
.\sl-dotnet-agent\SL.DotNet.exe run --buildSessionIdFile buildSessionId.txt --labId "<lab-id>" --includeNamespace "MyCompany.*" --instrumentationMode coverage --target "C:\MyApplication\App.exe" --workingDir "C:\WorkingDir" --targetArgs "-Flag1 true"
```

{% endcode %}
{% endtab %}

{% tab title="Bash" %}
{% code overflow="wrap" lineNumbers="true" %}

```bash
./sl-dotnet-agent/SL.DotNet run --buildSessionIdFile buildSessionId.txt --labId "<lab-id>" --includeNamespace "MyCompany.*" --instrumentationMode coverage --target "/opt/my-app/MyApplication" --workingDir "/opt/my-app" --targetArgs "--flag1 true"
```

{% endcode %}
{% endtab %}
{% endtabs %}

{% hint style="info" %}
This replaces the regular startup command for the application you want to profile.
{% endhint %}

{% hint style="success" %}
When the flow starts correctly, **Cockpit → Live Agents Monitor** shows the `testListener` and `Profiler` entries for the application.
{% endhint %}

{% hint style="info" %}
See [Command Reference](/knowledgebase/setup-and-configuration/sealights-agents-and-plugins/.net-core-agent/command-reference.md#starting-background-test-listener) for full parameter details.
{% endhint %}

## Running the agent as a background listener <a href="#running-the-sealights-.net-core-agent-as-a-background-listener" id="running-the-sealights-.net-core-agent-as-a-background-listener"></a>

Use this flow when the application command must stay unchanged.

### Start the background listener <a href="#starting-the-sealights-.net-core-agent-background-listener" id="starting-the-sealights-.net-core-agent-background-listener"></a>

Start the listener with a unique session key.

{% tabs %}
{% tab title="PowerShell" %}
{% code overflow="wrap" lineNumbers="true" %}

```powershell
.\sl-dotnet-agent\SL.DotNet.exe startBackgroundTestListener --buildSessionIdFile buildSessionId.txt --labId "<lab-id>" --includeNamespace "MyCompany.*" --testListenerSessionKey SL_CovCollectorAgent
```

{% endcode %}
{% endtab %}

{% tab title="Bash" %}
{% code overflow="wrap" lineNumbers="true" %}

```bash
./sl-dotnet-agent/SL.DotNet startBackgroundTestListener --buildSessionIdFile buildSessionId.txt --labId "<lab-id>" --includeNamespace "MyCompany.*" --testListenerSessionKey SL_CovCollectorAgent
```

{% endcode %}
{% endtab %}
{% endtabs %}

### Set the agent as a profiler <a href="#setting-the-sealights-.net-core-agent-as-a-profiler" id="setting-the-sealights-.net-core-agent-as-a-profiler"></a>

Set these environment variables in the same session that starts the application.

{% tabs %}
{% tab title="PowerShell" %}
{% code overflow="wrap" lineNumbers="true" %}

```powershell
$Env:CORECLR_ENABLE_PROFILING = "1"
$Env:CORECLR_PROFILER = "{01CA2C22-DC03-4FF5-8350-59E32A3536BA}"
$Env:CORECLR_PROFILER_PATH_32 = "C:\Sealights\agent\SL.DotNet.ProfilerLib.Windows_x86.dll"
$Env:CORECLR_PROFILER_PATH_64 = "C:\Sealights\agent\SL.DotNet.ProfilerLib.Windows_x64.dll"
$Env:SL_CollectorId = "SL_CovCollectorAgent"
$Env:SL_LogDir = "C:\Sealights\logs"
$Env:SL_LogLevel = "6"
```

{% endcode %}
{% endtab %}

{% tab title="Bash" %}
{% code overflow="wrap" lineNumbers="true" %}

```bash
export CORECLR_ENABLE_PROFILING=1
export CORECLR_PROFILER="{3B1DAA64-89D4-4999-ABF4-6A979B650B7D}"
export CORECLR_PROFILER_PATH_32="/usr/local/lib/libSL.DotNet.ProfilerLib.Linux.so"
export CORECLR_PROFILER_PATH_64="/usr/local/lib/libSL.DotNet.ProfilerLib.Linux.so"
export SL_CollectorId="SL_CovCollectorAgent"
export SL_LogDir="/tmp/logs"
export SL_LogLevel="6"
```

{% endcode %}
{% endtab %}
{% endtabs %}

{% hint style="warning" %}

* Ensure the variables specifying the profiler path are correct, given where you installed the agent binaries (for example: `CORECLR_PROFILER_PATH_32=/usr/local/lib/libSL.DotNet.ProfilerLib.Linux.so`)
* You should **unset** the environment variables before running any process that you **do not want** to capture coverage from
* Prefer process-scoped variables instead of persistent machine or user variables.
  {% endhint %}

{% hint style="success" %}
After you start the application with its normal command, **Cockpit → Live Agents Monitor** shows the `testListener` and `Profiler` entries.
{% endhint %}

### Stop the background listener <a href="#stopping-the-sealights-.net-core-agent-background-listener" id="stopping-the-sealights-.net-core-agent-background-listener"></a>

When coverage collection is complete, stop the listener with the same session key.

{% tabs %}
{% tab title="PowerShell" %}
{% code overflow="wrap" lineNumbers="true" %}

```powershell
.\sl-dotnet-agent\SL.DotNet.exe stopBackgroundTestListener --labId "<lab-id>" --testListenerSessionKey SL_CovCollectorAgent
```

{% endcode %}
{% endtab %}

{% tab title="Bash" %}
{% code overflow="wrap" lineNumbers="true" %}

```bash
./sl-dotnet-agent/SL.DotNet stopBackgroundTestListener --labId "<lab-id>" --testListenerSessionKey SL_CovCollectorAgent
```

{% endcode %}
{% endtab %}
{% endtabs %}

{% hint style="info" %}
See [Command Reference](/knowledgebase/setup-and-configuration/sealights-agents-and-plugins/.net-core-agent/command-reference.md) for full parameter details.
{% endhint %}


---

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