What changed in the plugin protocol for 0.92.0?

[tesujimath]

I just spent a bit of time bringing nu_plugin_bash_env up to date with the plugin protocol changes introduced in 0.91.0.

I had to abandon my API generator, as much of the plugin infrastructure has changed and become private. (I toyed with moving the API generator into the nu-plugin crate, but that was also not straightforward.)

So in the end I simply leaned on the description of the protocol for Python plugins and did it all by hand. This was quite tricky TBH, but I made it work, so bash-env 0.6.0 supports Nushell 0.91.0. 🎉

But now I see something changed again with the plugin protocol in Nushell 0.92.0, and I can't see what it was. I think the description on that Python plugin page may now be outdated.

Is updating that one someone's TODO list? It's really quite hard keeping a non-Rust plugin working!

I hope and expect the plugin protocol will stabilize soon!

[fdncred]

Have you read the release notes? https://www.nushell.sh/blog/2024-04-02-nushell_0_92_0.html You could also search for PRs by devyn and find a bunch of them related to plugins.

[tesujimath]

Yes I found those, thanks. And they're also helpful. 😊

[Abdillah]

The release note are super details. Unfortunately, it still hard to know what deserialization change affected on the new version. It would be great to note what the expected serialization especially Value (which only Int currently on the book) looks like..

[Abdillah]

How about a simple Rust deserialization tests?
It can mark and notice on some breaking change in the Plugin API, just like in #12326.

[fdncred]

@devyn has made many plugin changes recently and he's still working on some right now. i'm sure the plugin api will continue to change a little bit. more tests may be helpful. I'm sure devyn wouldn't mind other people jumping in with tests.

[devyn]

@Abdillah I absolutely have on my TODO list to document all of the Value types, so you will see that soon 🙂

[tesujimath]

This is what I needed to add to Nu itself to work out how to get my plugin working again.

[fdncred]

This is very cool. Nice work @tesujimath!

I'm wondering how it works on the latest main because register is being deprecated in favor of plugin add, which isn't just a rename but works completely differently now. plugin.nu is going away in favor of plugin.msgpackz and there are other plugin changes.

[tesujimath]

I had a quick look at plugin add, but I don't think its working sufficiently well for me to progress yet. It doesn't seem to be able to let you add and use even one of the bundled plugins:

aya> cargo build --workspace
    Finished dev [unoptimized + debuginfo] target(s) in 0.38s
aya> cargo run
    Finished dev [unoptimized + debuginfo] target(s) in 0.30s
     Running `target/debug/nu`
aya> version
╭────────────────────┬─────────────────────────────────────────────────╮
│ version            │ 0.92.3                                          │
│ major              │ 0                                               │
│ minor              │ 92                                              │
│ patch              │ 3                                               │
│ branch             │ main                                            │
│ commit_hash        │ fbb4fad7ac8985751c12fd6a6382b867f7f6c095        │
│ build_os           │ linux-x86_64                                    │
│ build_target       │ x86_64-unknown-linux-gnu                        │
│ rust_version       │ rustc 1.77.2 (25ef9e3d8 2024-04-09)             │
│ cargo_version      │ cargo 1.77.2 (e52e36006 2024-03-26)             │
│ build_time         │ 1980-01-01 00:00:00 +00:00                      │
│ build_rust_channel │ debug                                           │
│ allocator          │ mimalloc                                        │
│ features           │ default, sqlite, system-clipboard, trash, which │
│ installed_plugins  │                                                 │
╰────────────────────┴─────────────────────────────────────────────────╯
aya> plugin list
╭────────────╮
│ empty list │
╰────────────╯
aya> plugin add target/debug/nu_plugin_formats
aya> plugin list
╭────────────╮
│ empty list │
╰────────────╯

Should list nu_plugin_formats, surely?

I'm happy to try again when this has stabilized sufficiently

[devyn]

Hi, sorry, plugin add is not exactly the same thing as register. We decided to split the command in to two parts because spawning plugin executables at parse time was undesirable. At the REPL, the equivalent is this:

> plugin add target/debug/nu_plugin_formats
> plugin use formats

With plugin use now being the way to load something previously added. plugin use runs at parse-time like register did but it doesn't have to run a plugin executable, because it just relies on whatever's already been added to the plugin registry file. Of course, restarting nushell reloads everything as well, so you don't have to plugin use every time you want to use a plugin.

If you take a look at help plugin and the subcommands that should (hopefully) be descriptive enough, but I've also got PRs ready to update the docs on release, and the release notes will be pretty descriptive too.

[devyn]

Oh, and as a side note, I bet you can actually create a wrapper that abuses the --shell functionality. You can have nushell launch plugins with an auxilary program using

plugin add --shell /path/to/program /path/to/nu_plugin_foo

[tesujimath]

Thanks @devyn I got this working now with the new plugin system. I decided to use --shell as you suggest, which is much nicer than trying to infer the plugin name. 🎉