# Description
The local socket PR introduced a `Waitable` type, which could either
hold a value or be waited on until a value is available. Unlike a
channel, it would always return that value once set.
However, one issue with this design was that there was no way to detect
whether a value would ever be written. This splits the writer into a
different type `WaitableMut`, so that when it is dropped, waiting
threads can fail (because they'll never get a value).
# Tests + Formatting
A test has been added to `stress_internals` to make sure this fails in
the right way.
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# Description
Adds support for running plugins using local socket communication
instead of stdio. This will be an optional thing that not all plugins
have to support.
This frees up stdio for use to make plugins that use stdio to create
terminal UIs, cc @amtoine, @fdncred.
This uses the [`interprocess`](https://crates.io/crates/interprocess)
crate (298 stars, MIT license, actively maintained), which seems to be
the best option for cross-platform local socket support in Rust. On
Windows, a local socket name is provided. On Unixes, it's a path. The
socket name is kept to a relatively small size because some operating
systems have pretty strict limits on the whole path (~100 chars), so on
macOS for example we prefer `/tmp/nu.{pid}.{hash64}.sock` where the hash
includes the plugin filename and timestamp to be unique enough.
This also adds an API for moving plugins in and out of the foreground
group, which is relevant for Unixes where direct terminal control
depends on that.
TODO:
- [x] Generate local socket path according to OS conventions
- [x] Add support for passing `--local-socket` to the plugin executable
instead of `--stdio`, and communicating over that instead
- [x] Test plugins that were broken, including
[amtoine/nu_plugin_explore](https://github.com/amtoine/nu_plugin_explore)
- [x] Automatically upgrade to using local sockets when supported,
falling back if it doesn't work, transparently to the user without any
visible error messages
- Added protocol feature: `LocalSocket`
- [x] Reset preferred mode to `None` on `register`
- [x] Allow plugins to detect whether they're running on a local socket
and can use stdio freely, so that TUI plugins can just produce an error
message otherwise
- Implemented via `EngineInterface::is_using_stdio()`
- [x] Clean up foreground state when plugin command exits on the engine
side too, not just whole plugin
- [x] Make sure tests for failure cases work as intended
- `nu_plugin_stress_internals` added
# User-Facing Changes
- TUI plugins work
- Non-Rust plugins could optionally choose to use this
- This might behave differently, so will need to test it carefully
across different operating systems
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
- [ ] Document local socket option in plugin contrib docs
- [ ] Document how to do a terminal UI plugin in plugin contrib docs
- [ ] Document: `EnterForeground` engine call
- [ ] Document: `LeaveForeground` engine call
- [ ] Document: `LocalSocket` protocol feature
# Description
In the plugin protocol, I had used `#[serde(untagged)]` on the `Stream`
variant to make it smaller and include all of the stream messages at the
top level, but unfortunately this causes serde to make really unhelpful
errors if anything fails to decode anywhere:
```
Error: nu:🐚:plugin_failed_to_decode
× Plugin failed to decode: data did not match any variant of untagged enum PluginOutput
```
If you are trying to develop something using the plugin protocol
directly, this error is incredibly unhelpful. Even as a user, this
basically just says 'something is wrong'. With this change, the errors
are much better:
```
Error: nu:🐚:plugin_failed_to_decode
× Plugin failed to decode: unknown variant `PipelineDatra`, expected one of `Error`, `Signature`, `Ordering`, `PipelineData` at line 2 column 37
```
The only downside is it means I have to duplicate all of the
`StreamMessage` variants manually, but there's only 4 of them and
they're small.
This doesn't actually change the protocol at all - everything is still
identical on the wire.
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# Description
This allows plugins to view the source code of spans.
Requested by @ayax79 for implementing `polars ls`. Note that this won't
really help you find the location of the span. I'm planning to add
another engine call that will return information more similar to what
shows up in the miette diagnostics, with filename / line number / some
context, but I'll want to refactor some of the existing logic to make
that happen, so it was easier to just do this first. I hope this is
enough to at least have something somewhat useful show up for `polars
ls`.
# User-Facing Changes
- Example plugin: added `example view span` command
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
- [ ] Add to plugin protocol reference
# Description
Requested by @ayax79. This makes the custom value behavior more correct,
by calling the methods on the plugin to handle the custom values in
examples rather than the methods on the custom values themselves. This
helps for handle-type custom values (like what he's doing with
dataframes).
- Equality checking in `PluginTest::test_examples()` changed to use
`PluginInterface::custom_value_partial_cmp()`
- Base value rendering for `PluginSignature` changed to use
`Plugin::custom_value_to_base_value()`
- Had to be moved closer to `serve_plugin` for this reason, so the test
for writing signatures containing custom values was removed
- That behavior should still be tested to some degree, since if custom
values are not handled, signatures will fail to parse, so all of the
other tests won't work.
# User-Facing Changes
- `Record::sort_cols()` method added to share functionality required by
`PartialCmp`, and it might also be slightly faster
- Otherwise, everything should mostly be the same but better. Plugins
that don't implement special handling for custom values will still work
the same way, because the default implementation is just a pass-through
to the `CustomValue` methods.
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# Description
This keeps plugin custom values that have requested drop notification
around during the lifetime of a plugin call / stream by sending them to
a channel that gets persisted during the lifetime of the call.
Before this change, it was very likely that the drop notification would
be sent before the plugin ever had a chance to handle the value it
received.
Tests have been added to make sure this works - see the `custom_values`
plugin.
cc @ayax79
# User-Facing Changes
This is basically just a bugfix, just a slightly big one.
However, I did add an `as_mut_any()` function for custom values, to
avoid having to clone them. This is a breaking change.
# Description
The second `Value` is redundant and will consume five extra bytes on
each transmission of a custom value to/from a plugin.
# User-Facing Changes
This is a breaking change to the plugin protocol.
The [example in the protocol
reference](https://www.nushell.sh/contributor-book/plugin_protocol_reference.html#value)
becomes
```json
{
"Custom": {
"val": {
"type": "PluginCustomValue",
"name": "database",
"data": [36, 190, 127, 40, 12, 3, 46, 83],
"notify_on_drop": true
},
"span": {
"start": 320,
"end": 340
}
}
}
```
instead of
```json
{
"CustomValue": {
...
}
}
```
# After Submitting
Update plugin protocol reference
# Description
This is something that was discussed in the core team meeting last
Wednesday. @ayax79 is building `nu-plugin-polars` with all of the
dataframe commands into a plugin, and there are a lot of them, so it
would help to make the API more similar. At the same time, I think the
`Command` API is just better anyway. I don't think the difference is
justified, and the types for core commands have the benefit of requiring
less `.into()` because they often don't own their data
- Broke `signature()` up into `name()`, `usage()`, `extra_usage()`,
`search_terms()`, `examples()`
- `signature()` returns `nu_protocol::Signature`
- `examples()` returns `Vec<nu_protocol::Example>`
- `PluginSignature` and `PluginExample` no longer need to be used by
plugin developers
# User-Facing Changes
Breaking API for plugins yet again 😄
# Description
When implementing a `Command`, one must also import all the types
present in the function signatures for `Command`. This makes it so that
we often import the same set of types in each command implementation
file. E.g., something like this:
```rust
use nu_protocol::ast::Call;
use nu_protocol::engine::{Command, EngineState, Stack};
use nu_protocol::{
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, PipelineData,
ShellError, Signature, Span, Type, Value,
};
```
This PR adds the `nu_engine::command_prelude` module which contains the
necessary and commonly used types to implement a `Command`:
```rust
// command_prelude.rs
pub use crate::CallExt;
pub use nu_protocol::{
ast::{Call, CellPath},
engine::{Command, EngineState, Stack},
record, Category, Example, IntoInterruptiblePipelineData, IntoPipelineData, IntoSpanned,
PipelineData, Record, ShellError, Signature, Span, Spanned, SyntaxShape, Type, Value,
};
```
This should reduce the boilerplate needed to implement a command and
also gives us a place to track the breadth of the `Command` API. I tried
to be conservative with what went into the prelude modules, since it
might be hard/annoying to remove items from the prelude in the future.
Let me know if something should be included or excluded.
# Description
There wasn't really a good way to implement a command group style (e.g.
`from`, `query`, etc.) command in the past that just returns the help
text even if `--help` is not passed. This adds a new engine call that
just does that.
This is actually something I ran into before when developing the dbus
plugin, so it's nice to fix it.
# User-Facing Changes
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
- [ ] Document `GetHelp` engine call in proto
# Description
This makes `LabeledError` much more capable of representing close to
everything a `miette::Diagnostic` can, including `ShellError`, and
allows plugins to generate multiple error spans, codes, help, etc.
`LabeledError` is now embeddable within `ShellError` as a transparent
variant.
This could also be used to improve `error make` and `try/catch` to
reflect `LabeledError` exactly in the future.
Also cleaned up some errors in existing plugins.
# User-Facing Changes
Breaking change for plugins. Nicer errors for users.
[Context on
Discord](https://discord.com/channels/601130461678272522/855947301380947968/1219425984990806207)
# Description
- Rename `CustomValue::value_string()` to `type_name()` to reflect its
usage better.
- Change print behavior to always call `to_base_value()` first, to give
the custom value better control over the output.
- Change `describe --detailed` to show the type name as the subtype,
rather than trying to describe the base value.
- Change custom `Type` to use `type_name()` rather than `typetag_name()`
to make things like `PluginCustomValue` more transparent
One question: should `describe --detailed` still include a description
of the base value somewhere? I'm torn on it, it seems possibly useful
for some things (maybe sqlite databases?), but having `describe -d` not
include the custom type name anywhere felt weird. Another option would
be to add another method to `CustomValue` for info to be displayed in
`describe`, so that it can be more type-specific?
# User-Facing Changes
Everything above has implications for printing and `describe` on custom
values
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# Description
@ayax79 says that the dataframe commands all have dataframe custom
values in their examples, and they're used for tests.
Rather than send the custom values to the engine, if they're in
examples, this change just renders them using `to_base_value()` first.
That way we avoid potentially having to hold onto custom values in
`plugins.nu` that might not be valid indefinitely - as will be the case
for dataframes in particular - but we still avoid forcing plugin writers
to not use custom values in their examples.
# User-Facing Changes
- Custom values usable in plugin examples
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
# Description
Adds the `AddEnvVar` plugin call, which allows plugins to set
environment variables in the caller's scope. This is the first engine
call that mutates the caller's stack, and opens the door to more
operations like this if needed.
This also comes with an extra benefit: in doing this, I needed to
refactor how context was handled, and I was able to avoid cloning
`EngineInterface` / `Stack` / `Call` in most cases that plugin calls are
used. They now only need to be cloned if the plugin call returns a
stream. The performance increase is welcome (5.5x faster on `inc`!):
```nushell
# Before
> timeit { 1..100 | each { |i| $"2.0.($i)" | inc -p } }
405ms 941µs 952ns
# After
> timeit { 1..100 | each { |i| $"2.0.($i)" | inc -p } }
73ms 68µs 749ns
```
# User-Facing Changes
- New engine call: `add_env_var()`
- Performance enhancement for plugin calls
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
- [x] Document env manipulation in plugins guide
- [x] Document `AddEnvVar` in plugin protocol
# Description
This adds three engine calls: `GetEnvVar`, `GetEnvVars`, for getting
environment variables from the plugin command context, and
`GetCurrentDir` for getting the current working directory.
Plugins are now launched in the directory of their executable to try to
make improper use of the current directory without first setting it more
obvious. Plugins previously launched in whatever the current directory
of the engine was at the time the plugin command was run, but switching
to persistent plugins broke this, because they stay in whatever
directory they launched in initially.
This also fixes the `gstat` plugin to use `get_current_dir()` to
determine its repo location, which was directly affected by this
problem.
# User-Facing Changes
- Adds new engine calls (`GetEnvVar`, `GetEnvVars`, `GetCurrentDir`)
- Runs plugins in a different directory from before, in order to catch
bugs
- Plugins will have to use the new engine calls if they do filesystem
stuff to work properly
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
- [ ] Document the working directory behavior on plugin launch
- [ ] Document the new engine calls + response type (`ValueMap`)
# Description
Adds support for the following operations on plugin custom values, in
addition to `to_base_value` which was already present:
- `follow_path_int()`
- `follow_path_string()`
- `partial_cmp()`
- `operation()`
- `Drop` (notification, if opted into with
`CustomValue::notify_plugin_on_drop`)
There are additionally customizable methods within the `Plugin` and
`StreamingPlugin` traits for implementing these functions in a way that
requires access to the plugin state, as a registered handle model such
as might be used in a dataframes plugin would.
`Value::append` was also changed to handle custom values correctly.
# User-Facing Changes
- Signature of `CustomValue::follow_path_string` and
`CustomValue::follow_path_int` changed to give access to the span of the
custom value itself, useful for some errors.
- Plugins using custom values have to be recompiled because the engine
will try to do custom value operations that aren't supported
- Plugins can do more things 🎉
# Tests + Formatting
Tests were added for all of the new custom values functionality.
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
- [ ] Document protocol reference `CustomValueOp` variants:
- [ ] `FollowPathInt`
- [ ] `FollowPathString`
- [ ] `PartialCmp`
- [ ] `Operation`
- [ ] `Dropped`
- [ ] Document `notify_on_drop` optional field in `PluginCustomValue`
# Description
This allows plugins to make calls back to the engine to get config,
evaluate closures, and do other things that must be done within the
engine process.
Engine calls can both produce and consume streams as necessary. Closures
passed to plugins can both accept stream input and produce stream output
sent back to the plugin.
Engine calls referring to a plugin call's context can be processed as
long either the response hasn't been received, or the response created
streams that haven't ended yet.
This is a breaking API change for plugins. There are some pretty major
changes to the interface that plugins must implement, including:
1. Plugins now run with `&self` and must be `Sync`. Executing multiple
plugin calls in parallel is supported, and there's a chance that a
closure passed to a plugin could invoke the same plugin. Supporting
state across plugin invocations is left up to the plugin author to do in
whichever way they feel best, but the plugin object itself is still
shared. Even though the engine doesn't run multiple plugin calls through
the same process yet, I still considered it important to break the API
in this way at this stage. We might want to consider an optional
threadpool feature for performance.
2. Plugins take a reference to `EngineInterface`, which can be cloned.
This interface allows plugins to make calls back to the engine,
including for getting config and running closures.
3. Plugins no longer take the `config` parameter. This can be accessed
from the interface via the `.get_plugin_config()` engine call.
# User-Facing Changes
<!-- List of all changes that impact the user experience here. This
helps us keep track of breaking changes. -->
Not only does this have plugin protocol changes, it will require plugins
to make some code changes before they will work again. But on the plus
side, the engine call feature is extensible, and we can add more things
to it as needed.
Plugin maintainers will have to change the trait signature at the very
least. If they were using `config`, they will have to call
`engine.get_plugin_config()` instead.
If they were using the mutable reference to the plugin, they will have
to come up with some strategy to work around it (for example, for `Inc`
I just cloned it). This shouldn't be such a big deal at the moment as
it's not like plugins have ever run as daemons with persistent state in
the past, and they don't in this PR either. But I thought it was
important to make the change before we support plugins as daemons, as an
exclusive mutable reference is not compatible with parallel plugin
calls.
I suggest this gets merged sometime *after* the current pending release,
so that we have some time to adjust to the previous plugin protocol
changes that don't require code changes before making ones that do.
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
I will document the additional protocol features (`EngineCall`,
`EngineCallResponse`), and constraints on plugin call processing if
engine calls are used - basically, to be aware that an engine call could
result in a nested plugin call, so the plugin should be able to handle
that.
# Description
This fixes a race condition where all interfaces to a plugin might have
been dropped, but both sides are still expecting input, and the
`PluginInterfaceManager` doesn't get a chance to see that the interfaces
have been dropped and stop trying to consume input.
As the manager needs to hold on to a writer, we can't automatically
close the stream, but we also can't interrupt it if it's in a waiting to
read. So the best solution is to send a message to the plugin that we
are no longer going to be sending it any plugin calls, so that it knows
that it can exit when it's done.
This race condition is a little bit tricky to trigger as-is, but can be
more noticeable when running plugins in a tight loop. If too many plugin
processes are spawned at one time, Nushell can start to encounter "too
many open files" errors, and not be very useful.
# User-Facing Changes
# Tests + Formatting
- 🟢 `toolkit fmt`
- 🟢 `toolkit clippy`
- 🟢 `toolkit test`
- 🟢 `toolkit test stdlib`
# After Submitting
I will need to add `Goodbye` to the protocol docs
