A session manager for the Niri Wayland compositor that automatically saves and restores your window layout.

• Periodic session saving with configurable interval
• Automatic session restoration on startup
• Backup management with configurable retention
• Graceful handling of window spawn failures
• Configurable retry logic for session restoration
• Custom app launch command mapping via TOML configuration

The program can be run with various command-line options:

niri-session-manager [OPTIONS]

--save-interval <MINUTES>     How often to save the session (default: 15)
--max-backup-count <COUNT>    Number of backup files to keep (default: 5)
--spawn-timeout <SECONDS>     How long to wait for windows to spawn (default: 5)
--retry-attempts <COUNT>      Number of restore attempts (default: 3)
--retry-delay <SECONDS>       Delay between retry attempts (default: 2)

The program supports mapping app IDs to custom launch commands via a TOML configuration file. This is useful for applications where the app ID doesn't match the executable name, or when special launch arguments are needed.

Configuration file location: $XDG_CONFIG_HOME/niri-session-manager/config.toml

Example configuration:

# Niri Session Manager Configuration

# Apps that should only have one instance
[single_instance_apps] 
apps = [
    "firefox",
    "zen"
]

#Application remapping
[app_mappings]

# flatpak remapping
"vesktop" = ["flatpak", "run", "dev.vencord.Vesktop"]
"discord" = ["flatpak", "run", "com.discordapp.Discord"]
"slack" = ["flatpak", "run", "com.slack.Slack"]
"obs" = ["flatpak", "run", "com.obsproject.Studio"]

# Simple command remapping
"com.mitchellh.ghostty" = ["ghostty"]
"org.wezfurlong.wezterm" = ["wezterm"]

# Commands with arguments
"firefox-custom" = ["firefox", "--profile", "default-release"]

If no configuration file exists, one will be created with example mappings.

{
  description = "Your NixOS configuration";
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    niri-session-manager.url = "github:MTeaHead/niri-session-manager";
  };
  outputs = { self, nixpkgs, niri-session-manager, ... }: {
    nixosConfigurations = {
      yourHost = nixpkgs.lib.nixosSystem {
        system = "x86_64-linux";
        modules = [
          # This is not a complete NixOS configuration; reference your normal configuration here.
          # Import the module
          niri-session-manager.nixosModules.niri-session-manager

          ({
            # Enable the service
            services.niri-session-manager.enable = true;
            # Optional: Configure the service
            services.niri-session-manager.settings = {
              save-interval = 30;  # Save every 30 minutes
              max-backup-count = 3;  # Keep 3 most recent backups
            };
          })
        ];
      };
    };
  };
}

Session data and backups are stored in:

• Session file: $XDG_DATA_HOME/niri-session-manager/session.json
• Backups: $XDG_DATA_HOME/niri-session-manager/session-{timestamp}.bak
• Configuration: $XDG_CONFIG_HOME/niri-session-manager/config.toml

• Use PID to fetch the actual process command

• Grab window size and further details for better placement when restoring windows