Add a `freenet service enable/disable` subcommand for running Freenet as a background user-level service

[sanity]

Summary:
We want to provide an easy way for users to run Freenet as a background service without requiring manual startup each time. The consensus is to add a freenet service enable and freenet service disable command (rather than “install/uninstall”). This subcommand will create user-level services—rather than system-wide ones—because Freenet doesn’t require privileged access. It’s also safer for alpha-grade software to be sandboxed under a non-root user by default.

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Detailed Proposal

1. Command-Line Interface Changes

• freenet service enable:
  • Sets up Freenet to run as a background, user-level service on startup.
  • Immediately starts Freenet in the background.
• freenet service disable:
  • Disables and removes the user-level service.
  • Stops Freenet if it’s currently running.

(Optional) You might later add freenet service status or freenet service logs, but for now, let’s focus on enable/disable.

2. Cross-Platform Approach

2.1 Linux (User-Level systemd Units)

1. Detect systemd (typical in most modern distributions):
   • Check if systemctl is available.
2. Create a user-level systemd unit:
   • The file can be placed under ~/.config/systemd/user/freenet.service.
   • Sample unit file:

     [Unit]
     Description=Freenet User Service
     
     [Service]
     Type=simple
     ExecStart=/usr/bin/freenet
     Restart=on-failure
     
     [Install]
     WantedBy=default.target
     

3. Enable the user service:

   systemctl --user daemon-reload
   systemctl --user enable freenet
   systemctl --user start freenet
   

4. Disable/Remove:

   systemctl --user stop freenet
   systemctl --user disable freenet
   rm ~/.config/systemd/user/freenet.service
   systemctl --user daemon-reload
   

5. Fallback (Non-systemd environments):
   • If there’s no systemd, optionally detect other init systems or provide a manual warning that auto-service mode is unavailable.

2.2 macOS (User-Level Launch Agents)

1. Generate a Launch Agent plist:
   • Typically goes in ~/Library/LaunchAgents/org.freenet.service.plist.
   • Example:

     <?xml version="1.0" encoding="UTF-8"?>
     <!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN"
     "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
     <plist version="1.0">
       <dict>
         <key>Label</key>
         <string>org.freenet.service</string>
         <key>ProgramArguments</key>
         <array>
           <string>/usr/local/bin/freenet</string>
         </array>
         <key>RunAtLoad</key>
         <true/>
         <key>KeepAlive</key>
         <true/>
       </dict>
     </plist>
     

2. Enable the user Launch Agent:

   launchctl load ~/Library/LaunchAgents/org.freenet.service.plist
   launchctl start org.freenet.service
   

3. Disable/Remove:

   launchctl stop org.freenet.service
   launchctl unload ~/Library/LaunchAgents/org.freenet.service.plist
   rm ~/Library/LaunchAgents/org.freenet.service.plist
   

2.3 Windows (User-Level Equivalent)

Windows doesn’t have an exact “user-level service” concept like Linux or macOS. However, we can mimic it in one of two ways:

1. Windows Services
   • By default, sc create sets up a system-level service. This requires administrator privileges. Since we want user-level, this approach may be more complicated, involving special configurations (e.g., run as the current user’s credentials).
2. Scheduled Task
   • An alternate method is creating a scheduled task that triggers on user logon to run Freenet in the background.
   • For example:

     schtasks /create /tn "FreenetUserService" /tr "C:\Path\To\freenet.exe" /sc onlogon
     

   • Disabling it:

     schtasks /delete /tn "FreenetUserService"
     

   • This is not a true “service” but still achieves “run Freenet automatically when this user logs in.”

Recommendation for Windows:

• Since the request is specifically user-level, a scheduled task is likely the simplest approach without requiring admin privileges.
• If a real service is preferred, you’ll need to prompt for admin rights and optionally configure the “Log on as” user.

3. Implementation Outline

• freenet service enable:

  1. Detect OS (Linux/macOS/Windows).
  2. If Linux, detect systemd and place a systemd user unit in ~/.config/systemd/user/.
  3. If macOS, place a Launch Agent plist in ~/Library/LaunchAgents/.
  4. If Windows, create a scheduled task (assuming no admin privileges).
  5. Immediately start the service so Freenet is running in background.

• freenet service disable:

  1. Detect OS.
  2. Reverse the above steps (stop and remove the service file or scheduled task).
  3. Confirm that Freenet is no longer running in background.

4. Error Handling & Reporting

• If systemd (or another manager) is unavailable, print a warning that the service can’t be enabled automatically.
• If a service file already exists and is enabled, warn or ask the user for confirmation before overriding.
• If a service cannot be stopped or removed, display the relevant error message.

5. Future Enhancements

• freenet service status for quick checks (running/stopped, logs, etc.).
• freenet service logs might show tail of logs if supported.
• Options for specifying a custom location of the Freenet binary or custom config paths.

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Conclusion:
Implementing freenet service enable/disable for user-level services will let Freenet run automatically in the background across Linux, macOS, and Windows (with some OS-specific variations). This reduces friction for newcomers and offers a safer default than system-wide installation.