Metalama / / Conceptual documentation / Configuring and troubleshooting / Enabling logging

Enabling logging

If you report a Metalama bug, you may be asked to send Metalama log files. These instructions teach you how to produce them.

Step 1. Install the Metalama CLI tool

Install the metalama .NET tool as described in Installing the Metalama Command Line Tool.

Step 2. Edit diagnostics.json

Execute the following command:

            metalama config edit diagnostics.


This should open a diagnostics.json file in your default editor. Edit this file as follows:

  1. In the logging/processes section, set to true the processes for which logging should be enabled:
    • Compiler: the compile-time process.
    • Rider: the design-time Roslyn process of the Rider IDE.
    • DevEnv: the UI process of Visual Studio (note that there is no aspect code running in this process).
    • RoslynCodeAnalysisService: the design-time Roslyn process running under Visual Studio (this is where the aspect code runs).
  2. In the logging/trace section, set to true the categories for which logging should be enabled. To enable logging for everything, allow the * category.

<<< In the following example, logging is enabled for the compiler process for all categories.

    "logging": {
        "processes": {
                "Other": false,
                "Compiler": true,
                "DevEnv": false,
                "RoslynCodeAnalysisService": false,
                "Rider": false,
                "BackstageWorker": false,
                "MetalamaConfig": false,
                "TestHost": false
    "trace": {
        "*": false
    "stopLoggingAfterHours": 5.0


To verify that the JSON file is correct, you can run the following:

            metalama config verify diagnostics


Step 3. Restart processes

Diagnostic settings are cached in all processes, including background compiler processes and IDE helper processes.

To restart background compiler processes, do the following:

            metalama kill


If you want to change the logging configuration of the IDE processes, restart your IDE manually.

Step 4. Execute Metalama

Execute the sequence of actions to be logged.


Logging is automatically disabled after a specified number of hours since the last modification of diagnostics.json. The time value is taken from the stopLoggingAfterHours property in the logging section and defaults to 2 hours. You can edit diagnostics.json to change the value.

Step 5. Open the log file

You will find the log under the %TEMP%\Metalama\Logs directory.