Logging from powershell-script to csharp-program (log4net - logfile)

Question

I have written a program with C#, that creates a logfile and fills this by using log4net. This program starts powershell-scripts. The scripts should use log4net, too. I want

Answer 1

I do not have details specific to log4net but it should be possible to load log4net like any other .Net component:

Accessing .NET components from Powershell Powershell Calling .NET Assembly that uses App.config

Answer 2

As an alternative you could reroute the streams and use the standard Write-Error, Write-Verbose, etc. CMDlets in your Script.

In your C# app attach methods to the streams events, like so:

PowerShell ps = PowerShell.Create();
// ... code to add your script, etc.
ps.Streams.Warning.DataAdded += new EventHandler<DataAddedEventArgs>(Warning_DataAdded);
// ... attach more streams for other log levels
ps.Invoke();

Create your methods like so:

static void Warning_DataAdded(object sender, DataAddedEventArgs e)
{
    PSDataCollection<WarningRecord> warningStream = (PSDataCollection<WarningRecord>)sender;
    log.Warn(warningStream[e.Index].Message);
}

This should write everything you output in your PowerShell Script via

Write-Warning "This is a warning message"

to the Warn level in log4net.

Answer 3

You could define some functions and pass them to your script as variables:

    static void Log(string message) {
        // log4net code here...
    }

    void ExecuteScript() {

        // create the runspace configuration
        RunspaceConfiguration runspaceConfiguration = RunspaceConfiguration.Create();

        // create the runspace, open it and add variables for the script
        Runspace runspace = RunspaceFactory.CreateRunspace(runspaceConfiguration);
        runspace.Open();

        // pass the Log function as a variable
        runspace.SessionStateProxy.SetVariable("Log", (Action<string>)Log);
        // etc...

Then you can invoke the function from the script like this:

$Log.Invoke("test")

EDIT: to add a logging level, you should do something like

    static void Log(LogLevel level,string message) {
        // log4net code here...
    }

     void ExecuteScript() {
        // ...
        runspace.SessionStateProxy.SetVariable("Log", (Action<LogLevel,string>)Log);