Signal Handler Configuration
By default, Python will install signal handlers for certain signals, such as SIGINT (Ctrl+C) and SIGTERM. This can interfere with the normal operation of your application, especially if you are using a framework that has its own signal handlers.
When Python handles these signals instead of your .NET application, it can prevent proper shutdown procedures and interrupt normal signal processing in your C# code.
Understanding the Issue
Default Python Behavior
Python automatically installs signal handlers for:
- SIGINT (Ctrl+C) - Keyboard interrupt
- SIGTERM - Termination request
- SIGPIPE - Broken pipe
- Other signals depending on the platform
This means that signal handlers on C# code will not be called when the signal is received, and the Python code will handle the signal instead.
Impact on .NET Applications
// This C# signal handler might not work as expected
Console.CancelKeyPress += (sender, e) =>
{
Console.WriteLine("C# handling Ctrl+C");
// This might not be called if Python handles SIGINT first
e.Cancel = true;
};
Disabling Python Signal Handlers
You can disable this behavior by using the .DisableSignalHandlers() method on the Python environment configuration:
var builder = Host.CreateApplicationBuilder();
var pb = builder.Services.WithPython()
.WithHome(Environment.CurrentDirectory)
.FromRedistributable()
.DisableSignalHandlers(); // Disable Python signal handlers
var app = builder.Build();
env = app.Services.GetRequiredService<IPythonEnvironment>();