phoxal 0.30.0

Phoxal - production-oriented autonomous robot framework: the runtime engine and model (the api contract tree lives in phoxal-api, the typed bus in phoxal-bus).
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218

//! The static metadata traits the macros target (D50/D59/D60).
//!
//! - [`ParticipantSpec`] is emitted by `#[derive(phoxal::Service)]`,
//!   `#[derive(phoxal::Driver)]`, `#[derive(phoxal::Tool)]`, or
//!   `#[derive(phoxal::Simulator)]`: the artifact kind/class, id, the one API
//!   version, the config type, and the field-side contracts.
//! - [`ParticipantBehavior`] is emitted by `#[phoxal::behavior]`: the server-side
//!   contracts plus the lifecycle dispatch (`__setup`/`__step`/`__shutdown`) the
//!   runner drives.
//! - [`DeclaresPublish`]/[`DeclaresSubscribe`]/[`DeclaresQuery`] are per-participant
//!   markers (also emitted by the derive) that make `SetupContext` builders reject
//!   undeclared contract families/directions at compile time (D44).
//! - [`TypedGraphSurface`] is emitted by checked participant derives and gates
//!   `#[step]` / `#[server]` / `#[server_snapshot]` away from thin `Tool`
//!   runners.
//!
//! The full required-contract set is the union of [`ParticipantSpec::FIELD_CONTRACTS`]
//! and [`ParticipantBehavior::SERVER_CONTRACTS`]; `emit-apis` builds that union at
//! when `emit-apis` runs (see [`participant_metadata`](crate::participant::emit::participant_metadata)),
//! so there is no concatenated const slice.

use std::future::Future;
use std::pin::Pin;
use std::sync::Arc;
use std::time::Duration;

use schemars::JsonSchema;
use serde::Serialize;

use crate::bus::ApiVersion;
use crate::participant::context::{SetupContext, ShutdownContext, StepContext};
use crate::participant::server::ServerOutcome;

/// One `{api_version, schema_id, family}` contract a participant participates
/// in. Built by the macros from a body type's
/// [`ContractBody`](crate::bus::ContractBody) consts so family/schema/version
/// are single-sourced from the api tree. Compatibility is judged by `schema_id`
/// agreement per `family` alone (#16-b); which topic or direction a participant
/// happens to use is not part of that judgment, so it is not carried here.
#[derive(Clone, Copy, Debug, Serialize)]
pub struct ContractUse {
    /// The API version of the body (`<Body::Api as ApiVersion>::ID`).
    pub api_version: &'static str,
    /// The transitive wire-shape id (`<Body as ContractBody>::SCHEMA_ID`).
    pub schema_id: &'static str,
    /// The contract family id (`<Body as ContractBody>::FAMILY`).
    pub family: &'static str,
}

/// Static metadata derived from a participant struct.
pub trait ParticipantSpec: Sized + Send + 'static {
    /// The authoring kind that produced this artifact.
    const KIND: &'static str;
    /// Whether normal graph topology applies to this participant.
    const PARTICIPANT_CLASS: &'static str;
    /// The participant id (`#[phoxal(id = "…")]`, default kebab of the type name).
    const ID: &'static str;
    /// The one API version this participant runs against. The graph may mix
    /// generations: compatibility is per-contract `schema_id` agreement (#16).
    type Api: ApiVersion;
    /// `<Self::Api as ApiVersion>::ID`, for metadata.
    const API_VERSION: &'static str;
    /// The participant's typed config (`()` for official participants that read the
    /// robot model directly).
    type Config: serde::de::DeserializeOwned + JsonSchema + Send + 'static;
    /// The contracts derived from the struct's handle fields.
    const FIELD_CONTRACTS: &'static [ContractUse];
}

/// Marker emitted only by checked participant derives that expose the typed graph
/// surface (`#[step]` / `#[server]` / `#[server_snapshot]`).
#[diagnostic::on_unimplemented(
    message = "`{Self}` is a `Tool`, which is a thin raw-bus runner and has no typed-graph surface",
    label = "`#[step]` / `#[server]` is not allowed here; use the raw bus (`phoxal::raw`) instead"
)]
pub trait TypedGraphSurface {}

/// Marker emitted only by `#[derive(phoxal::Driver)]`.
#[doc(hidden)]
pub trait IsDriver {}

/// Marker emitted only by `#[derive(phoxal::Tool)]`.
#[doc(hidden)]
pub trait IsTool {}

/// Marker emitted only by `#[derive(phoxal::Simulator)]`.
#[doc(hidden)]
pub trait IsSimulator {}

/// Lifecycle dispatch + server-side metadata (`#[phoxal::behavior]`).
///
/// The async methods are awaited by the runner in its own task (no `Send` bound
/// is required because the participant future is not spawned).
#[allow(async_fn_in_trait)]
pub trait ParticipantBehavior: ParticipantSpec {
    /// Contracts derived from `#[server]`/`#[server_snapshot]` signatures (empty
    /// until the query slice).
    const SERVER_CONTRACTS: &'static [ContractUse];

    /// The committed-snapshot state type (`()` when there is no `#[snapshot]`).
    type Snapshot: Send + Sync + 'static;

    /// Whether the participant provides a committed snapshot (`#[snapshot]`).
    const HAS_SNAPSHOT: bool;

    /// The versionless topic keys of exclusive `#[server]` handlers.
    fn __exclusive_server_topics() -> &'static [&'static str];

    /// The versionless topic keys of concurrent `#[server_snapshot]` handlers.
    fn __snapshot_server_topics() -> &'static [&'static str];

    /// Validate explicit server topic expressions before startup declares
    /// queryables. The macro rejects an explicit key that differs from the
    /// request body's canonical topic and rejects duplicate server topics.
    fn __validate_server_topics() -> std::result::Result<(), String>;

    /// The scheduled-step cadence, or `None` if the participant has no `#[step]`.
    fn __step_schedule() -> Option<StepSchedule>;

    /// Construct the participant (`#[setup]`).
    async fn __setup(ctx: &mut SetupContext<Self>, config: Self::Config) -> crate::Result<Self>;

    /// Run one scheduled step (`#[step]`; a no-op when none is declared).
    async fn __step(&mut self, step: StepContext) -> crate::Result<()>;

    /// Graceful shutdown (`#[shutdown]`; a no-op when none is declared).
    async fn __shutdown(&mut self, ctx: ShutdownContext) -> crate::Result<()>;

    /// Commit the current state as a snapshot (calls the `#[snapshot]` provider;
    /// returns `()` when there is none).
    fn __take_snapshot(&self) -> Self::Snapshot;

    /// Serve one exclusive `#[server]` query (holds `&mut self`, serialized with
    /// `#[step]`). Awaited on the runner's main task. The request's
    /// `schema_id`/`family` (from bus metadata) are validated against the
    /// handler's request body before decode.
    async fn __serve_exclusive(
        &mut self,
        topic: &str,
        api_version: &str,
        schema_id: &str,
        family: &str,
        request: &[u8],
    ) -> ServerOutcome;

    /// Serve one concurrent `#[server_snapshot]` query against a committed
    /// snapshot. Returns a boxed `Send` future so the runner can spawn it.
    fn __serve_snapshot(
        snapshot: Arc<Self::Snapshot>,
        topic: String,
        api_version: String,
        schema_id: String,
        family: String,
        request: Vec<u8>,
    ) -> Pin<Box<dyn Future<Output = ServerOutcome> + Send>>;
}

/// Per-participant marker that this participant declared a *publish* handle for body `B`
/// (D44). Emitted by the derive for each `Publisher<B>` field; the
/// `SetupContext::publisher` builder carries `where Self: DeclaresPublish<B>`, so
/// publishing a family/direction the struct never declared is a compile error
/// (and would otherwise be IO `emit-apis` never reports).
pub trait DeclaresPublish<B: ?Sized> {}

/// Per-participant marker that this participant declared a *subscribe* handle for body
/// `B` (`Subscriber<B>`/`Latest<B>` fields). See [`DeclaresPublish`].
pub trait DeclaresSubscribe<B: ?Sized> {}

/// Per-participant marker that this participant declared a *query* handle for
/// `Req`/`Resp` (`Querier<Req, Resp>` fields). See [`DeclaresPublish`].
pub trait DeclaresQuery<Req: ?Sized, Resp: ?Sized> {}

/// The cadence + missed-tick policy of a `#[step(hz = …)]` loop (D34).
#[derive(Clone, Copy, Debug)]
pub struct StepSchedule {
    /// Target frequency in Hz.
    pub hz: f64,
    /// What to do after an overrun.
    pub missed_tick: MissedTick,
}

impl StepSchedule {
    /// A schedule at `hz` with the default (`Collapse`) missed-tick policy.
    pub const fn hz(hz: f64) -> Self {
        StepSchedule {
            hz,
            missed_tick: MissedTick::Collapse,
        }
    }

    /// The nominal step period.
    pub fn period(&self) -> Duration {
        std::cmp::max(
            Duration::from_secs_f64(1.0 / self.hz),
            Duration::from_nanos(1),
        )
    }
}

/// Missed-tick policy after a step overruns its period (D34).
#[derive(Clone, Copy, Debug, PartialEq, Eq)]
pub enum MissedTick {
    /// Run a single step after an overrun and record `missed_ticks`; no burst
    /// catch-up. The v1 default.
    Collapse,
    /// Replay every missed tick. Reserved for offline replay.
    CatchUp,
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn step_schedule_period_never_rounds_to_zero() {
        assert_eq!(StepSchedule::hz(f64::MAX).period(), Duration::from_nanos(1));
    }
}