init programs.gns3

[ghost]

Description of changes

GNS3 is already a package, but it depends on a few other packages in order to function properly. These are now managed by the programs.gns3 option.

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 23.11 Release Notes (or backporting 23.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

Priorities

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[h7x4]

Just wondering, is this a duplicate of #252790?

[ghost]

What's the difference with "inherit(lib)"? Isn't the effect the same? Does that mean that " with maintainers; " should also be an "inherit(maintainers)"?BTW, this is taken from the firefox programs module.

[AndersonTorres]

What's the difference with "inherit(lib)"? Isn't the effect the same?

"The effect" is not the only thing that matters - even because inherit (lib) is not equivalent to with lib.

It is about control and predictability.

If you have some knowledge about Python, with lib is similar to from lib import *.
You are bringing all the functions from lib into the scope of the whole file.
On the other hand, inherit (lib) mkOption mdDoc is similar to from lib import mkOptions mdDoc, bringing only the specified functions into the scope.

Does that mean that " with maintainers; " should also be an "inherit(maintainers)"?

Ideally, with should be abolished. Copying the best practices guide:

1. Static analysis can’t reason about the code, because it would have to actually evaluate the with'ed file to see which names are in scope.
2. The scoping rules are not intuitive
3. When more than one with is used, it’s not clear anymore where the names are coming from.

BTW, this is taken from the firefox programs module.

Many failures do not make a success.

#208242

[ghost]

Thanks @AndersonTorres for the explanation. I was not aware of the difference. nix is in dire need of a linter like clippy for rust that is run on all PRs by the CICD, but that's a topic for another time.

@h7x4 the other PR adds a systemd service for the gns3 server, which is good if you have a separate machine for the gns3 server and want to access it from clients on separate machines running the gns3 GUI client. For a local machine, a constantly running gns3 server is unnecessary.

The usecase for this PR is a user looking to have all dependencies for the GUI client and a local gns3 server.
gns3-gui starts the server when needed and stops it (configured to do so by default) when exited. The server is run with user running gns3-gui.
The GUI also has additional dependencies (a terminal emulator and telnet, and a remote desktop client for nodes that are accessible with VNC).