| 1 | //! Boot-time snapshot pruning. |
| 2 | //! |
| 3 | //! Called from `session_manager` once per session start. Failure is |
| 4 | //! never fatal — old snapshots taking disk space is annoying but not |
| 5 | //! correctness-breaking, so we log and move on. |
| 6 | |
| 7 | use std::io; |
| 8 | use std::path::Path; |
| 9 | use std::time::Duration; |
| 10 | |
| 11 | use super::paths::snapshot_git_dir; |
| 12 | use super::repo::SnapshotRepo; |
| 13 | |
| 14 | /// Default snapshot retention window: 7 days. |
| 15 | pub const DEFAULT_MAX_AGE: Duration = Duration::from_secs(7 * 24 * 60 * 60); |
| 16 | |
| 17 | /// Prune snapshots older than `max_age` for the given workspace. |
| 18 | /// |
| 19 | /// If no snapshot repo exists yet (first run) this is a cheap no-op. |
| 20 | /// Returns the number of snapshots removed. |
| 21 | pub fn prune_older_than(workspace: &Path, max_age: Duration) -> io::Result<usize> { |
| 22 | let git_dir = snapshot_git_dir(workspace); |
| 23 | if !git_dir.exists() { |
| 24 | return Ok(0); |
| 25 | } |
| 26 | let repo = SnapshotRepo::open_or_init(workspace)?; |
| 27 | let removed = repo.prune_older_than(max_age)?; |
| 28 | // `git prune --expire=now` walks the whole object store — seconds on a |
| 29 | // large snapshot repo. Nothing removed means nothing newly unreachable, |
| 30 | // so skip the walk entirely on the common boot path (#3757). |
| 31 | if removed > 0 { |
| 32 | repo.prune_unreachable_objects()?; |
| 33 | } |
| 34 | Ok(removed) |
| 35 | } |
| 36 | |
| 37 | #[cfg(test)] |
| 38 | mod tests { |
| 39 | use super::*; |
| 40 | use crate::test_support::lock_test_env; |
| 41 | use tempfile::tempdir; |
| 42 | |
| 43 | /// Same guard shape as in `repo::tests` — pins HOME for the lifetime |
| 44 | /// of one test under the process-wide env mutex. |
| 45 | struct ScopedHome { |
| 46 | prev: Option<std::ffi::OsString>, |
| 47 | _guard: crate::test_support::TestEnvLock, |
| 48 | } |
| 49 | impl Drop for ScopedHome { |
| 50 | fn drop(&mut self) { |
| 51 | // SAFETY: process-wide lock still held. |
| 52 | unsafe { |
| 53 | match self.prev.take() { |
| 54 | Some(v) => std::env::set_var("HOME", v), |
| 55 | None => std::env::remove_var("HOME"), |
| 56 | } |
| 57 | } |
| 58 | } |
| 59 | } |
| 60 | fn scoped_home(home: &std::path::Path) -> ScopedHome { |
| 61 | let guard = lock_test_env(); |
| 62 | let prev = std::env::var_os("HOME"); |
| 63 | // SAFETY: serialised by the global env lock. |
| 64 | unsafe { |
| 65 | std::env::set_var("HOME", home); |
| 66 | } |
| 67 | ScopedHome { |
| 68 | prev, |
| 69 | _guard: guard, |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | #[test] |
| 74 | fn prune_no_repo_returns_zero() { |
| 75 | let tmp = tempdir().unwrap(); |
| 76 | let _home = scoped_home(tmp.path()); |
| 77 | let removed = prune_older_than(tmp.path(), DEFAULT_MAX_AGE).unwrap(); |
| 78 | assert_eq!(removed, 0); |
| 79 | } |
| 80 | |
| 81 | #[test] |
| 82 | fn prune_with_existing_repo_zero_age_clears_all() { |
| 83 | let tmp = tempdir().unwrap(); |
| 84 | let _home = scoped_home(tmp.path()); |
| 85 | let workspace = tmp.path().join("ws"); |
| 86 | std::fs::create_dir_all(&workspace).unwrap(); |
| 87 | let repo = SnapshotRepo::open_or_init(&workspace).unwrap(); |
| 88 | std::fs::write(workspace.join("f.txt"), "x").unwrap(); |
| 89 | repo.snapshot("turn:0").unwrap(); |
| 90 | |
| 91 | // Same-second flake guard: see `repo::tests`. |
| 92 | std::thread::sleep(Duration::from_millis(1100)); |
| 93 | |
| 94 | let removed = prune_older_than(&workspace, Duration::from_secs(0)).unwrap(); |
| 95 | assert!(removed >= 1); |
| 96 | } |
| 97 | } |
| 98 |