borg/harness/

opencode.rs

//! opencode 1.x and 2.x: the TS plugin `adapters/opencode/borg.ts`, compiled in and copied to
//! `~/.config/opencode/plugins/borg.ts` (`$OPENCODE_CONFIG_DIR`, `$XDG_CONFIG_HOME/opencode`). The plugin
//! translates both ways, sends opencode's pid, emulates the stop's second round and gives borg the
//! stop's budget (`BUDGETS`, which borg's first answer tells it).

use std::ffi::OsStr;
use std::path::{Path, PathBuf};
use std::time::{Duration, Instant};

use serde_json::Value;

use crate::runner;

use super::{Budgets, CONTEXT_GUARD, Caps, DroneWake, Harness, Probe, Run, STOP_TIMEOUT_S, SubAgent, Transcript, Wiring};

pub const ADAPTER: &str = include_str!("../../assets/adapters/opencode/borg.ts");

/// What the plugin waits for each of borg's answers. opencode limits no plugin hook, so each is a guard
/// against a hung borg holding the engineer's turn: a prompt waits 5 s and a tool result 2 s for borg's
/// context (file appends; a later answer is kept for the next call), a tool call 2 s before it runs (a
/// stat when nobody steers); the stop, and every call queued behind it, borg's stop timeout. The
/// session's end, queued too, gets the same as its own `end` (the plugin's end waits `end_ms`, the other
/// queued calls `stop_ms`): a hung end holds the session's queue and the plugin's cleanup, which ends
/// every session.
pub const BUDGETS: Budgets = Budgets {
    prompt: Duration::from_secs(5),
    pre_tool: Duration::from_secs(2),
    post_tool: Duration::from_secs(2),
    stop: Duration::from_secs(STOP_TIMEOUT_S),
    end: Duration::from_secs(STOP_TIMEOUT_S),
};

pub struct Opencode;

impl Harness for Opencode {
    fn name(&self) -> &'static str {
        "opencode"
    }

    fn caps(&self) -> Caps {
        Caps {
            prompt_context: true,
            tool_context: true,
            // The channels exist (borg.ts); turning these on waits for an evaluation.
            early_delivery: false,
            question_dialog: false,
            transcript: Transcript::None,
            deny_capture: true,
            sends_pid: true,
            // The plugin names it too (`BORG_STOP_BUDGET_MS`), as borg's answer told it.
            stop_budget: Some(BUDGETS.stop),
            // No limit (1.19.0): a tool's output is cut before tool.execute.after, never the text the
            // plugin appends there, and a prompt's synthetic part goes in whole. 2.x unverified here.
            context_chars: CONTEXT_GUARD,
            session_env: None,
            pid_env: Some("OPENCODE_PID"),
            drone_wake: DroneWake::Plugin,
        }
    }

    fn wiring(&self) -> Wiring {
        Wiring::AdapterFile { source: ADAPTER }
    }

    fn budgets(&self) -> Option<Budgets> {
        Some(BUDGETS)
    }

    fn target(&self, home: &Path, var: &dyn Fn(&str) -> Option<PathBuf>) -> PathBuf {
        let dir = var("OPENCODE_CONFIG_DIR").or_else(|| var("XDG_CONFIG_HOME").map(|x| x.join("opencode")));
        dir.unwrap_or_else(|| home.join(".config/opencode")).join("plugins/borg.ts")
    }

    fn probe(&self) -> Probe {
        Probe { cli: "opencode", tested: " (adapter tested with 1.18.32, 1.19.0, 2.0.23 and 2.0.29)" }
    }

    /// Each session's subagents, through opencode's CLI (read-only, as `borg assimilate` reads it), and
    /// only where opencode keeps data under `home` (`$XDG_DATA_HOME/opencode`, else
    /// `home/.local/share/opencode`). Every session: 1.x only (2.x has no query that lists them).
    fn sub_runs(&self, home: &Path, session: Option<&str>, since: Option<i64>) -> Vec<Run> {
        let data = std::env::var_os("XDG_DATA_HOME").filter(|v| !v.is_empty()).map_or_else(|| home.join(".local/share"), PathBuf::from);
        if !data.join("opencode").is_dir() {
            return Vec::new();
        }
        let here = std::env::current_dir().unwrap_or_else(|_| std::env::temp_dir());
        session_runs(session, since, &|id, dir| export(id, dir.unwrap_or(&here)), &db)
    }
}

// ---------------------------------------------------------------- the CLI

/// Guard: how long one opencode CLI call (the query, a listing, one export) may take, so a hung CLI
/// never stalls `borg assimilate` or a session's end.
const CLI_CAP: Duration = Duration::from_secs(30);

/// `opencode <args>` in `dir`, the `opencode` on `path` (None: this process's PATH), capped like a
/// model call (a hung CLI never stalls the run). PWD names the dir too: opencode takes the project
/// from it, not from the process cwd. 2.x (`v2`) gets a model call's env (`runner::standalone_env`):
/// its private server would otherwise load every plugin and the project's own config in the
/// engineer's repos. The output goes to a file in a private scratch dir: opencode exits before a
/// full pipe drains, so a large export read through a pipe arrives cut off (seen on 1.19 at 72 KiB),
/// while a file gets all of it. Here, beside the harness, so `borg assimilate` and the subagent reader
/// share it without harness/ depending on assimilate.rs (arch.sh M5).
pub(crate) fn cli(v2: bool, path: Option<&OsStr>, args: &[String], dir: &Path) -> Option<Vec<u8>> {
    let scratch = runner::Scratch::new("opencode-out")?;
    let out = scratch.0.join("out.json");
    let mut cmd = std::process::Command::new("sh");
    cmd.args(["-c", r#"umask 077; out="$1"; shift; exec opencode "$@" > "$out""#, "sh"]).arg(&out).args(args);
    cmd.current_dir(dir).env("PWD", dir).env("OPENCODE_DISABLE_AUTOUPDATE", "1");
    if v2 {
        let empty = scratch.0.join("config");
        std::fs::create_dir(&empty).ok()?;
        runner::standalone_env(&mut cmd, Some(&empty), runner::engineers_config());
    }
    if let Some(p) = path {
        cmd.env("PATH", p);
    }
    runner::run_capped(cmd, None, CLI_CAP)?;
    std::fs::read(&out).ok()
}

/// The arguments that export session `id` (2.x always `--standalone`: a private server).
pub(crate) fn export_args(v2: bool, id: &str) -> Vec<String> {
    let head: &[&str] = if v2 { &["session", "export", "--standalone"] } else { &["export", "--pure"] };
    head.iter().map(|a| a.to_string()).chain(std::iter::once(id.to_string())).collect()
}

/// One session's export through this machine's opencode CLI, run in `dir`.
fn export(id: &str, dir: &Path) -> Option<Value> {
    let v2 = runner::opencode() == runner::Opencode::V2;
    cli(v2, None, &export_args(v2, id), dir).and_then(|o| serde_json::from_slice(&o).ok())
}

/// The rows of a read-only query of opencode 1.x's database; None on 2.x, which has no such query,
/// or when the call fails.
fn db(sql: &str) -> Option<Vec<Value>> {
    if runner::opencode() == runner::Opencode::V2 {
        return None;
    }
    let args: Vec<String> = ["db", "--pure", "--format", "json", sql].iter().map(|a| a.to_string()).collect();
    cli(false, None, &args, &std::env::temp_dir()).and_then(|o| serde_json::from_slice(&o).ok())
}

// ---------------------------------------------------------------- subagents

/// Exports a session by id, in the directory given (else wherever it runs).
pub type Export<'a> = &'a dyn Fn(&str, Option<&Path>) -> Option<Value>;
/// Runs a read-only query of opencode 1.x's database (None: no such query).
pub type Query<'a> = &'a dyn Fn(&str) -> Option<Vec<Value>>;

/// A guard, not a tuning knob: at most this many children of one session are exported, the rest read
/// from the parent's copy of their final text.
pub const CHILDREN: usize = 20;
/// Guard: all of one session's exports stop after this long; the remaining children are read from the
/// parent.
const SESSION_BUDGET: Duration = Duration::from_secs(120);

/// An opencode session id (`ses_` and alphanumerics), the only thing passed to its CLI.
fn session_id(s: &str) -> bool {
    s.starts_with("ses_") && s.chars().all(|c| c.is_ascii_alphanumeric() || c == '_')
}

/// One run per main session that started subagents, oldest first: `session` (a `ses_…` id) only, else
/// every parent of a subagent session since `since` (1.x's query). A subagent is a child session; the
/// parent's task tool call (1.x `task`, 2.x `subagent`) names it (`metadata.sessionId`/`sessionID`)
/// with its description, agent and prompt, and holds its final text. Its export gives its cwd and
/// work. opencode has no structured output: `output` stays None.
pub fn session_runs(session: Option<&str>, since: Option<i64>, export: Export, query: Query) -> Vec<Run> {
    let roots: Vec<String> = match session {
        Some(s) if session_id(s) => vec![s.to_string()],
        Some(_) => Vec::new(),
        None => {
            let since = since.map(|ms| format!(" AND time_created >= {ms}")).unwrap_or_default();
            let sql = format!("SELECT parent_id AS id, MIN(time_created) AS t FROM session WHERE parent_id IS NOT NULL{since} GROUP BY parent_id ORDER BY t");
            query(&sql).unwrap_or_default().iter().filter_map(|r| r["id"].as_str().filter(|s| session_id(s)).map(String::from)).collect()
        }
    };
    let mut runs: Vec<Run> = roots
        .iter()
        .filter_map(|id| {
            let until = Instant::now() + SESSION_BUDGET;
            run_of(&export(id, None)?, export, until)
        })
        .collect();
    runs.sort_by_key(|r| r.started);
    runs
}

/// A message's parts: 1.x `parts`, 2.x `content`.
fn parts(m: &Value) -> impl Iterator<Item = &Value> {
    m["parts"].as_array().or(m["content"].as_array()).into_iter().flatten()
}

fn assistant(m: &Value) -> bool {
    m["info"]["role"] == "assistant" || m["type"] == "assistant"
}

fn text(v: &Value) -> String {
    match v {
        Value::String(s) => s.clone(),
        Value::Array(bs) => bs.iter().filter_map(|b| b["text"].as_str()).collect::<Vec<_>>().join("\n"),
        _ => String::new(),
    }
}

/// The run of `root`'s children: each exported while the id is valid, fewer than `CHILDREN` were and
/// `until` has not passed; else read from the parent's copy of its final text.
fn run_of(root: &Value, export: Export, until: Instant) -> Option<Run> {
    let info = &root["info"];
    let dir = info["directory"].as_str().or(info["location"]["directory"].as_str()).unwrap_or_default();
    let mut agents = Vec::new();
    let mut exported = 0;
    for m in root["messages"].as_array().into_iter().flatten() {
        let at = m["info"]["time"]["created"].as_i64().or(m["time"]["created"].as_i64()).unwrap_or(0);
        for p in parts(m).filter(|p| p["type"] == "tool") {
            let state = &p["state"];
            let Some(child) = state["metadata"]["sessionId"].as_str().or(state["metadata"]["sessionID"].as_str()) else { continue };
            let input = &state["input"];
            let s = |k: &str| input[k].as_str().unwrap_or_default().to_string();
            let started = state["time"]["start"].as_i64().or(p["time"]["created"].as_i64()).unwrap_or(at);
            let mut a = SubAgent {
                label: s("description"),
                kind: input["subagent_type"].as_str().map_or_else(|| s("agent"), String::from),
                started,
                prompt: s("prompt"),
                cwd: dir.to_string(),
                ..Default::default()
            };
            let read = session_id(child) && exported < CHILDREN && Instant::now() < until;
            exported += usize::from(read);
            match read.then(|| export(child, (!dir.is_empty()).then_some(Path::new(dir)))).flatten() {
                Some(c) => from_export(&mut a, &c),
                // Without its export (or not read), its final text as the parent saw it.
                None => {
                    a.work = state["output"].as_str().map_or_else(|| text(&state["content"]), String::from);
                    a.final_text = a.work.clone();
                }
            }
            agents.push(a);
        }
    }
    if agents.is_empty() {
        return None;
    }
    agents.sort_by_key(|a| a.started);
    let id = info["id"].as_str().unwrap_or_default().to_string();
    let started = info["time"]["created"].as_i64().unwrap_or(agents[0].started);
    Some(Run { session: id.clone(), id, name: info["title"].as_str().unwrap_or_default().to_string(), started, agents, loose: false })
}

/// A child's work from its export `c`: its cwd when the export names one, and its assistant parts.
fn from_export(a: &mut SubAgent, c: &Value) {
    let ci = &c["info"];
    if let Some(d) = ci["directory"].as_str().or(ci["location"]["directory"].as_str()) {
        a.cwd = d.to_string();
    }
    for p in c["messages"].as_array().into_iter().flatten().filter(|m| assistant(m)).flat_map(parts) {
        match p["type"].as_str() {
            Some("tool") => a.called(&p["state"]["input"]),
            Some("text") => a.said(p["text"].as_str().unwrap_or_default()),
            _ => {}
        }
    }
}

#[cfg(test)]
mod tests {
    use super::*;
    use serde_json::json;
    use std::cell::RefCell;

    /// A parent with one task call per child id, each with its final text.
    fn parent(children: &[String]) -> Value {
        let parts: Vec<Value> = children
            .iter()
            .map(|c| json!({"type": "tool", "state": {"input": {"description": c}, "metadata": {"sessionId": c}, "output": format!("parent's copy of {c}")}}))
            .collect();
        json!({"info": {"id": "ses_root", "directory": "/w/app"}, "messages": [{"info": {"role": "assistant"}, "parts": parts}]})
    }

    fn child(id: &str) -> Value {
        json!({"info": {"directory": "/w/app"}, "messages": [{"info": {"role": "assistant"}, "parts": [{"type": "text", "text": format!("export of {id}")}]}]})
    }

    #[test]
    fn only_valid_ids_are_exported_and_at_most_children_of_them() {
        let asked = RefCell::new(Vec::new());
        let export = |id: &str, _: Option<&Path>| {
            asked.borrow_mut().push(id.to_string());
            Some(child(id))
        };
        let mut ids: Vec<String> = (0..CHILDREN + 5).map(|i| format!("ses_c{i}")).collect();
        ids.insert(0, "--help".into());
        ids.insert(1, "ses_../x".into());
        let run = run_of(&parent(&ids), &export, Instant::now() + SESSION_BUDGET).unwrap();
        let asked = asked.into_inner();
        assert_eq!(asked.len(), CHILDREN, "{asked:?}");
        assert!(asked.iter().all(|id| session_id(id)), "{asked:?}");
        let works: Vec<&str> = run.agents.iter().map(|a| a.work.trim()).collect();
        assert_eq!((works[0], works[1], works[2]), ("parent's copy of --help", "parent's copy of ses_../x", "export of ses_c0"));
        assert_eq!(works.last().copied(), Some(format!("parent's copy of ses_c{}", CHILDREN + 4).as_str()));
    }

    #[test]
    fn past_the_sessions_deadline_children_are_read_from_the_parent() {
        let export = |_: &str, _: Option<&Path>| -> Option<Value> { panic!("no export after the deadline") };
        let run = run_of(&parent(&["ses_c0".into()]), &export, Instant::now()).unwrap();
        assert_eq!(run.agents[0].work, "parent's copy of ses_c0");
    }
}