vtcode_memory/
retention.rs

1//! Retention and garbage-collection for the unified session store.
2
3use std::path::Path;
4use std::time::{Duration, SystemTime, UNIX_EPOCH};
5
6use walkdir::WalkDir;
7
8use crate::error::SessionStoreError;
9use crate::query::SessionSummary;
10use crate::sessions_root;
11
12/// Retention policy applied to the set of per-session stores.
13#[derive(Debug, Clone, Copy)]
14pub struct RetentionPolicy {
15    /// Maximum number of sessions to keep (oldest evicted first).
16    pub max_sessions: usize,
17    /// Maximum age of a session in days before eviction.
18    pub max_age_days: u64,
19}
20
21impl Default for RetentionPolicy {
22    fn default() -> Self {
23        Self { max_sessions: 50, max_age_days: 30 }
24    }
25}
26
27/// Apply the retention policy, removing the oldest / stale sessions.
28///
29/// Returns the number of sessions removed. This bounds the otherwise
30/// unbounded growth of `.vtcode/sessions/` so overhead does not accumulate
31/// on disk across a long-lived agent.
32pub fn apply_retention(workspace: &Path, policy: RetentionPolicy) -> Result<usize, SessionStoreError> {
33    let root = sessions_root(workspace);
34    if !root.exists() {
35        return Ok(0);
36    }
37    let mut sessions: Vec<SessionSummary> = crate::query::recent_sessions(workspace, usize::MAX);
38    let mut removed = 0usize;
39
40    // Phase 1: evict oldest sessions beyond the count cap.
41    if sessions.len() > policy.max_sessions {
42        sessions.sort_by(|a, b| a.updated_at.cmp(&b.updated_at));
43        let to_remove = sessions.len() - policy.max_sessions;
44        for s in sessions.iter().take(to_remove) {
45            remove_session(&root.join(&s.session_id))?;
46            removed += 1;
47        }
48        // Drop evicted entries so phase 2 doesn't double-remove.
49        sessions.drain(..to_remove);
50    }
51
52    // Phase 2: evict sessions older than max_age_days (regardless of count).
53    let cutoff = age_cutoff(policy.max_age_days);
54    for s in &sessions {
55        if older_than(s.updated_at.as_str(), cutoff) {
56            remove_session(&root.join(&s.session_id))?;
57            removed += 1;
58        }
59    }
60
61    Ok(removed)
62}
63
64/// Remove the legacy `history/` and `logs/` directories after they have been
65/// imported into the unified store by [`crate::migrate_legacy`].
66///
67/// Returns the number of bytes freed. The legacy `checkpoints/` directory is
68/// intentionally left in place until `/revert` is rewired to the unified
69/// store; callers should confirm revert behavior before deleting it manually.
70pub fn gc_legacy(workspace: &Path) -> Result<u64, SessionStoreError> {
71    let vt = workspace.join(".vtcode");
72    let mut freed = 0u64;
73    for name in ["history", "logs"] {
74        let dir = vt.join(name);
75        if dir.exists() {
76            freed += dir_size(&dir);
77            std::fs::remove_dir_all(&dir).map_err(|e| SessionStoreError::io(dir.clone(), e))?;
78        }
79    }
80    Ok(freed)
81}
82
83fn remove_session(dir: &Path) -> Result<(), SessionStoreError> {
84    if dir.exists() {
85        std::fs::remove_dir_all(dir).map_err(|e| SessionStoreError::io(dir.to_path_buf(), e))?;
86    }
87    Ok(())
88}
89
90fn dir_size(dir: &Path) -> u64 {
91    WalkDir::new(dir)
92        .into_iter()
93        .filter_map(Result::ok)
94        .filter(|e| e.file_type().is_file())
95        .filter_map(|e| e.metadata().ok())
96        .map(|m| m.len())
97        .sum()
98}
99
100fn age_cutoff(max_age_days: u64) -> SystemTime {
101    SystemTime::now() - Duration::from_secs(max_age_days * 24 * 3600)
102}
103
104fn older_than(rfc3339: &str, cutoff: SystemTime) -> bool {
105    let Ok(dt) = chrono::DateTime::parse_from_rfc3339(rfc3339) else {
106        return false;
107    };
108    let cutoff_secs = cutoff
109        .duration_since(UNIX_EPOCH)
110        .map(|d| d.as_secs() as i64)
111        .unwrap_or(i64::MAX);
112    dt.timestamp() < cutoff_secs
113}
vtcode_memory/retention.rs

vtcode_memory/
retention.rs
