relayburn_cli/harnesses/

mod.rs

//! Legacy harness substrate — Rust port of `packages/cli/src/harnesses/types.ts`
//! and friends.
//!
//! The CLI no longer exposes a command that launches agent processes, but
//! these adapters remain as unit-tested reference code for launcher
//! integrations built on the SDK pending-stamp primitives. Every adapter
//! contributes the same five-step shape:
//!
//! 1. **`plan`** — compute the spawn plan (binary + args + env). Per-harness
//!    transports inject session ids or hook arguments here.
//! 2. **`before_spawn`** — fire any pre-spawn side effect: stamp now if the
//!    session id is known up front (claude path), or drop a pending-stamp
//!    manifest the post-spawn ingest pass will resolve (codex / opencode).
//! 3. **`start_watcher`** *(optional)* — return a [`WatchController`]
//!    (re-exported from `relayburn_sdk`) that drains a session-store
//!    directory while the child runs. Adapters that ingest a single
//!    pre-known session file (claude) return `None` here; adapters that
//!    share the pending-stamp shape (codex, opencode) wire the watch loop
//!    through [`pending_stamp::adapter`].
//! 4. **`after_exit`** — run a final ingest pass after the child exits and
//!    return an [`IngestReport`] for the launcher to report.
//! 5. The launcher itself owns step zero — collecting `cwd`, passthrough
//!    args, and any user-provided enrichment tags into a [`PlanCtx`] —
//!    and step six — joining the watcher and reporting summary stats.
//!
//! ## Trait shape vs the TS sibling
//!
//! `HarnessAdapter` is a `Send + Sync` trait object so the registry can
//! hand out `&'static dyn HarnessAdapter` references. `async fn` in trait
//! is mediated by `async_trait::async_trait` to keep adapter impls
//! ergonomic; the desugared `Pin<Box<dyn Future + Send>>` is easy for
//! launcher code to spawn and join at the top level.

use std::path::PathBuf;

use async_trait::async_trait;
use relayburn_sdk::{Enrichment, IngestReport, WatchController};

pub mod claude;
pub mod codex;
pub mod opencode;
pub mod pending_stamp;
pub mod registry;

#[cfg(test)]
pub(crate) mod test_env;

pub use registry::{list_harness_names, lookup};

/// Driver-side context handed to every adapter call. Mirrors the TS
/// `HarnessRunContext` shape one-to-one (`cwd`, `passthrough`, `tags`,
/// `spawnStartTs`) plus the Rust port's typed ledger-home override.
///
/// `tags` is a `BTreeMap<String, String>` (re-exported from the SDK as
/// [`Enrichment`]) so insertion order doesn't matter for the on-disk
/// stamp record — the pending-stamp serializer canonicalizes ordering.
#[derive(Debug, Clone)]
pub struct PlanCtx {
    /// Working directory for the spawned harness so it picks up
    /// project-local config.
    pub cwd: PathBuf,
    /// Argv tail the launcher wants to pass through. Adapters splice
    /// this into their generated argv via [`SpawnPlan::args`].
    pub passthrough: Vec<String>,
    /// User-supplied enrichment that will be merged onto the resulting
    /// stamp. Keys are free-form (`task`, `pr`, …).
    pub tags: Enrichment,
    /// Optional ledger home selected by `--ledger-path`. Pending-stamp
    /// adapters use this for both manifest writes and ingest passes so
    /// read/write sidecars stay scoped to the same home without relying
    /// solely on process env mutation.
    pub ledger_home: Option<PathBuf>,
    /// Wall-clock timestamp captured by the driver immediately before
    /// `before_spawn`. Used by the pending-stamp manifest so the
    /// post-exit resolver can match against session-file mtimes.
    pub spawn_start_ts: std::time::SystemTime,
}

/// Spawn plan returned by [`HarnessAdapter::plan`]. Launcher code owns
/// the actual process construction; this struct is the per-adapter
/// contribution to it.
///
/// `session_id` is filled in by adapters that know the session id up
/// front (claude can mint one and inject it via `--session-id` so the
/// pre-spawn stamp is final from the start). Adapters that don't know
/// it ahead of time leave this `None` and rely on the pending-stamp
/// resolver to attach their enrichment to the freshly-discovered
/// session in `after_exit`.
#[derive(Debug, Clone, Default)]
pub struct SpawnPlan {
    pub binary: String,
    pub args: Vec<String>,
    /// Env vars to overlay on top of the parent process env when
    /// spawning. Keep this tight — `tokio::process::Command::env_clear`
    /// + this map is the typical pattern, though Wave 2 may relax that.
    pub env_overrides: Vec<(String, String)>,
    /// Session id the adapter pre-allocated, when known. See struct
    /// docs for when this is `Some` vs `None`.
    pub session_id: Option<String>,
}

impl SpawnPlan {
    /// Convenience: minimal plan that just runs `binary` with `args` and
    /// inherits the parent's env. Most adapters' `plan` returns this
    /// shape directly.
    pub fn new(binary: impl Into<String>, args: Vec<String>) -> Self {
        Self {
            binary: binary.into(),
            args,
            env_overrides: Vec::new(),
            session_id: None,
        }
    }
}

/// `HarnessAdapter` — five-method contract every harness implements. The
/// TS sibling lives at `packages/cli/src/harnesses/types.ts` and the
/// shape mirrors it; see the module docs for what each step does.
///
/// Adapters are zero-sized (or near-zero-sized) stateless types that the
/// registry hands out as `&'static dyn HarnessAdapter`. State that lives
/// across `before_spawn` → `after_exit` rides on `PlanCtx` / `SpawnPlan`,
/// or in the pending-stamps directory on disk.
#[async_trait]
pub trait HarnessAdapter: Send + Sync {
    /// Lowercase identifier — `claude`, `codex`, `opencode`, … — used as
    /// the dispatch key and as the harness label in log lines.
    fn name(&self) -> &'static str;

    /// Per-harness session-store root. Today this is a fixed path
    /// resolved against the user's home directory; future iterations
    /// may thread `BurnConfig` through so the root is configurable.
    fn session_root(&self) -> PathBuf;

    /// Compute the spawn plan. Inject session ids or transport-level
    /// args here. Populate `SpawnPlan::session_id` when known so
    /// `before_spawn` / `after_exit` can stamp eagerly.
    async fn plan(&self, ctx: &PlanCtx) -> anyhow::Result<SpawnPlan>;

    /// Pre-spawn side effects. Stamp now if the session id is in `plan`,
    /// otherwise drop a pending-stamp manifest the post-spawn ingest can
    /// resolve. Default impl is a no-op so simple adapters don't have to
    /// spell it out.
    async fn before_spawn(&self, _ctx: &PlanCtx, _plan: &SpawnPlan) -> anyhow::Result<()> {
        Ok(())
    }

    /// Optional. Return a [`WatchController`] from
    /// [`relayburn_sdk::start_watch_loop`] to drain a session store
    /// while the child runs; return `None` for adapters that ingest a
    /// single pre-known file at exit.
    ///
    /// `on_report` is a callback the driver routes into its summary
    /// accumulator so the final `[burn] <name> ingest:` line reflects
    /// every tick that fired during the run, not just `after_exit`.
    fn start_watcher(
        &self,
        _ctx: &PlanCtx,
        _on_report: relayburn_sdk::ReportSink,
    ) -> Option<WatchController> {
        None
    }

    /// Final ingest pass after the child exits. Returns an
    /// [`IngestReport`] the driver folds into its summary line.
    async fn after_exit(&self, ctx: &PlanCtx, plan: &SpawnPlan) -> anyhow::Result<IngestReport>;
}

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

    /// Smoke test: `SpawnPlan::new` produces an inherit-env plan. Catches
    /// accidental shape changes on the struct.
    #[test]
    fn spawn_plan_new_minimal_shape() {
        let plan = SpawnPlan::new("claude", vec!["--help".into()]);
        assert_eq!(plan.binary, "claude");
        assert_eq!(plan.args, vec!["--help".to_string()]);
        assert!(plan.env_overrides.is_empty());
        assert!(plan.session_id.is_none());
    }

    /// Trait dispatch sanity: a fake adapter implementing `HarnessAdapter`
    /// must be coercible to `&dyn HarnessAdapter` so the registry can
    /// hand out trait-object references.
    struct FakeAdapter;

    #[async_trait]
    impl HarnessAdapter for FakeAdapter {
        fn name(&self) -> &'static str {
            "fake"
        }
        fn session_root(&self) -> PathBuf {
            PathBuf::from("/tmp/fake")
        }
        async fn plan(&self, _ctx: &PlanCtx) -> anyhow::Result<SpawnPlan> {
            Ok(SpawnPlan::new("fake", vec![]))
        }
        async fn after_exit(
            &self,
            _ctx: &PlanCtx,
            _plan: &SpawnPlan,
        ) -> anyhow::Result<IngestReport> {
            Ok(IngestReport::default())
        }
    }

    #[tokio::test]
    async fn fake_adapter_round_trip() {
        let adapter: &dyn HarnessAdapter = &FakeAdapter;
        assert_eq!(adapter.name(), "fake");
        assert_eq!(adapter.session_root(), PathBuf::from("/tmp/fake"));

        let ctx = PlanCtx {
            cwd: PathBuf::from("/tmp"),
            passthrough: vec![],
            tags: Enrichment::new(),
            ledger_home: None,
            spawn_start_ts: std::time::SystemTime::now(),
        };
        let plan = adapter.plan(&ctx).await.unwrap();
        assert_eq!(plan.binary, "fake");

        let report = adapter.after_exit(&ctx, &plan).await.unwrap();
        assert_eq!(report.scanned_sessions, 0);
        assert_eq!(report.ingested_sessions, 0);
    }
}