osandov
Commands - dot-prefixed, stdlib only
This is another stab at the idea of commands in drgn.
Rather than using IPython like the first PR I shared, this one is based on the stdlib only. It integrates into the existing drgn CLI via a subclass of InteractiveConsole. Commands are simply a callable, since I didn't want to get too opinionated with a class-based solution, or even requiring the use of argparse.
Commands in the CLI are prefixed by a . . No valid Python statement starts with that, so this shouldn't break any existing behavior. They are able to return results just like normal expressions, and they can access the locals too.
The drgn.cli module has a registry of commands, which can be added to using the @command("name") decorator. In order to ensure that user/third-party commands can be loaded, I've added a drgn.command.v1 entry point. Drgn automatically loads modules from that entry point prior to starting the CLI. (This is notable from a security standpoint. However, if you're running drgn as root, you would have needed to install that entry point as root as well.)
Just like globals and everything else, commands can be customized in run_interactive().
I've added three useful commands into the default set. These aren't the only ones I would be interested in adding, just a demonstration.
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.x- execute a script (basically a wrapper on execscript) -
.let- set a variable equal to a drgn object -
.contrib- run a contrib script by name
I also added support to the ptdrgn.py script because I use that constantly.
In any case, I hope that the code is pretty straightforward. I think this is the most simple and direct way I could come up with to do commands in drgn.
I fixed the Python 3.6-3.9 mypy failure which was present in the previous revision, but of course since I updated the pre-commit, you won't actually get a mypy run on 3.6 now. I don't have permissions to add the label to the PR, but it would be good to have CI run against all Python versions, just to verify. Of course I tested it locally on 3.9 and it worked.
I also rebased this on main. I even checked this in combination with the #364 changes and they don't conflict. With those changes, it's pretty impressive how much less verbose the command line is!
Very funny, I didn't realize that when Github Actions runs, it does an automatic merge with the main branch and then runs tests. I got failures from #364 because I guess the run happened in the brief window between the merge and the fix :)