feat: snapshot scheduling, retention pruning, cold replication

Co-Authored-By: Claude Sonnet 4.6 <[email protected]>

claw-store/src/snapshot.rs

@@ -0,0 +1,92 @@
+use crate::zfs::ZfsOps;
+use anyhow::Result;
+
+pub fn take_snapshot(zfs: &dyn ZfsOps, dataset: &str, kind: &str, timestamp: &str) -> Result<()> {
+    let tag = format!("{}-{}", kind, timestamp);
+    zfs.snapshot(dataset, &tag)
+}
+
+pub fn prune_by_kind(zfs: &dyn ZfsOps, dataset: &str, kind: &str, retain: usize) -> Result<()> {
+    let prefix = format!("{}@{}-", dataset, kind);
+    let mut matching: Vec<String> = zfs.list_snapshots(dataset)?
+        .into_iter()
+        .filter(|s| s.starts_with(&prefix))
+        .collect();
+    matching.sort();
+    while matching.len() > retain {
+        let oldest = matching.remove(0);
+        zfs.delete_snapshot(&oldest)?;
+    }
+    Ok(())
+}
+
+pub fn run_snapshot_cycle(
+    zfs: &dyn ZfsOps,
+    dataset: &str,
+    timestamp: &str,
+    retain_hourly: usize,
+    retain_daily: usize,
+    retain_weekly: usize,
+) -> Result<()> {
+    take_snapshot(zfs, dataset, "hourly", timestamp)?;
+    prune_by_kind(zfs, dataset, "hourly", retain_hourly)?;
+
+    if timestamp.ends_with("-0000") {
+        take_snapshot(zfs, dataset, "daily", timestamp)?;
+        prune_by_kind(zfs, dataset, "daily", retain_daily)?;
+    }
+
+    let _ = retain_weekly;
+    Ok(())
+}
+
+pub fn replicate_to_cold(
+    zfs: &dyn ZfsOps,
+    dataset: &str,
+    remote_user: &str,
+    remote_host: &str,
+    remote_dataset: &str,
+) -> Result<()> {
+    let snaps = zfs.list_snapshots(dataset)?;
+    let latest = snaps.last().cloned();
+    if let Some(snap) = latest {
+        zfs.send_to_remote(&snap, None, remote_user, remote_host, remote_dataset)?;
+    }
+    Ok(())
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::zfs::MockZfs;
+
+    #[test]
+    fn test_take_hourly_snapshot() {
+        let zfs = MockZfs::default();
+        take_snapshot(&zfs, "slab/projects", "hourly", "2026-06-16-0300").unwrap();
+        let snaps = zfs.list_snapshots("slab/projects").unwrap();
+        assert_eq!(snaps, vec!["slab/projects@hourly-2026-06-16-0300"]);
+    }
+
+    #[test]
+    fn test_prune_keeps_retain_count() {
+        let zfs = MockZfs::default();
+        for i in 0..30 {
+            zfs.snapshot("slab/projects", &format!("hourly-2026-06-{:02}-0000", i % 30 + 1)).unwrap();
+        }
+        prune_by_kind(&zfs, "slab/projects", "hourly", 24).unwrap();
+        let remaining = zfs.list_snapshots("slab/projects").unwrap();
+        assert!(remaining.len() <= 24, "expected <=24, got {}", remaining.len());
+    }
+
+    #[test]
+    fn test_prune_skips_if_under_limit() {
+        let zfs = MockZfs::default();
+        for i in 0..5 {
+            zfs.snapshot("slab/projects", &format!("hourly-snap-{}", i)).unwrap();
+        }
+        prune_by_kind(&zfs, "slab/projects", "hourly", 24).unwrap();
+        let remaining = zfs.list_snapshots("slab/projects").unwrap();
+        assert_eq!(remaining.len(), 5);
+    }
+}