speccoder_runtime/resume.rs
1//! Resuming an attempt a killed process left behind.
2//!
3//! Before an attempt, a marker records its admission key, the checkpoint it
4//! started from and the acceptance tests it is judged by. A run that ends in
5//! any ordinary way removes it ([`Guard`]); a killed process cannot, so a
6//! marker on disk means an attempt was interrupted. The next run then keeps
7//! the worktree as the attempt left it and admits the attempt under the same
8//! key: agentplane finds the interrupted run and resumes it from its journal
9//! — model calls and tool calls that finished are read back, not repeated —
10//! and a run that had already finished is read back whole and judged again
11//! (a task that passed just before the kill is ticked now).
12
13use std::path::{Path, PathBuf};
14
15use serde::{Deserialize, Serialize};
16use sha2::{Digest as _, Sha256};
17
18/// An attempt in progress.
19#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
20pub struct Marker {
21 /// The agentplane admission key.
22 pub key: String,
23 /// The checkpoint the attempt started from.
24 pub before: String,
25 /// The worktree's HEAD then; a different HEAD means the marker is stale.
26 pub head: String,
27 /// Which attempt of the task run.
28 pub attempt: u32,
29 /// Which best-of-n sample (0-based).
30 pub sample: usize,
31 /// The acceptance tests prepared for the task run.
32 pub acceptance: Option<serde_json::Value>,
33}
34
35/// Where the marker of `feature/task` lives.
36#[must_use]
37pub fn path(plane_dir: &Path, feature: &str, task: &str) -> PathBuf {
38 plane_dir
39 .join("resume")
40 .join(feature)
41 .join(format!("{task}.json"))
42}
43
44/// The marker, if an attempt was interrupted.
45#[must_use]
46pub fn load(path: &Path) -> Option<Marker> {
47 serde_json::from_str(&std::fs::read_to_string(path).ok()?).ok()
48}
49
50/// Records `marker` (written whole, then renamed: never half a marker).
51pub fn save(path: &Path, marker: &Marker) -> std::io::Result<()> {
52 if let Some(dir) = path.parent() {
53 std::fs::create_dir_all(dir)?;
54 }
55 let tmp = path.with_extension("json.tmp");
56 std::fs::write(
57 &tmp,
58 serde_json::to_vec(marker).map_err(std::io::Error::other)?,
59 )?;
60 std::fs::rename(tmp, path)
61}
62
63/// A fresh admission key: unique per attempt, so an ordinary rerun never
64/// meets an old attempt's run.
65#[must_use]
66pub fn new_key(feature: &str, task: &str) -> String {
67 static COUNTER: std::sync::atomic::AtomicU64 = std::sync::atomic::AtomicU64::new(0);
68 let nanos = std::time::SystemTime::now()
69 .duration_since(std::time::UNIX_EPOCH)
70 .map_or(0, |d| d.as_nanos());
71 let n = COUNTER.fetch_add(1, std::sync::atomic::Ordering::SeqCst);
72 let digest = Sha256::digest(format!(
73 "{feature}/{task}/{nanos}/{}/{n}",
74 std::process::id()
75 ));
76 let hex: String = digest.iter().take(16).map(|b| format!("{b:02x}")).collect();
77 format!("attempt-{hex}")
78}
79
80/// Removes the marker when a task run that started an attempt ends in any
81/// ordinary way. A run refused before its attempt starts (a session check,
82/// a worktree held by a waiting call) leaves an interrupted or waiting
83/// attempt's marker alone: that attempt still resumes.
84#[derive(Debug)]
85pub struct Guard {
86 path: PathBuf,
87 armed: std::cell::Cell<bool>,
88}
89
90impl Guard {
91 /// A guard for the marker at `path`, not yet armed.
92 #[must_use]
93 pub fn new(path: PathBuf) -> Self {
94 Self {
95 path,
96 armed: std::cell::Cell::new(false),
97 }
98 }
99
100 /// An attempt is starting: the marker goes when the run ends.
101 pub fn arm(&self) {
102 self.armed.set(true);
103 }
104
105 /// Leaves the marker in place: the attempt waits for a person and the
106 /// next run resumes it.
107 pub fn keep(self) {
108 self.armed.set(false);
109 }
110}
111
112impl Drop for Guard {
113 fn drop(&mut self) {
114 if self.armed.get() {
115 let _ = std::fs::remove_file(&self.path);
116 }
117 }
118}