M4

crates/odian-packs/src/manifest.rs

@@ -142,6 +142,20 @@ fn is_name(s: &str) -> bool {
     (1..=128).contains(&s.len()) && s.bytes().all(|b| b.is_ascii_alphanumeric() || matches!(b, b'_' | b'.' | b'-'))
 }
 
+/// Lower-case hyphenated uuid, as Postgres prints gen_random_uuid().
+fn is_uuid(s: &str) -> bool {
+    s.len() == 36
+        && s.bytes().enumerate().all(|(i, b)| match i {
+            8 | 13 | 18 | 23 => b == b'-',
+            _ => b.is_ascii_digit() || (b'a'..=b'f').contains(&b),
+        })
+}
+
+/// A Postgres xid8 in decimal.
+fn is_xid(s: &str) -> bool {
+    (1..=20).contains(&s.len()) && s.bytes().all(|b| b.is_ascii_digit())
+}
+
 fn is_snapshot(s: &str) -> bool {
     let b = s.as_bytes();
     b.len() == 16
@@ -216,6 +230,13 @@ pub fn validate(manifest: &Value) -> Result<()> {
             .ok_or_else(|| Error::manifest("db.snapshot must look like 20260915T101500Z"))?;
         let files = entries(db.get("files"), "db.files")?;
         require(!files.is_empty(), || "db.files must not be empty".into())?;
+        if let Some(sync) = db.get("sync") {
+            let db_id = sync.get("db_id").and_then(Value::as_str).is_some_and(is_uuid);
+            let horizon = sync.get("horizon").and_then(Value::as_str).is_some_and(is_xid);
+            require(db_id && horizon, || {
+                "db.sync must hold the DHP's db_id (a uuid) and a horizon (a transaction id)".into()
+            })?;
+        }
         let prefix = format!("db/{snapshot}/");
         let mut seen: HashSet<String> = HashSet::new();
         for (i, entry) in files.iter().enumerate() {
@@ -328,6 +349,18 @@ pub struct DbSection {
     pub schema_version: u64,
     pub snapshot: String,
     pub files: Vec<DbFile>,
+    /// Present when the snapshot comes from a DHP running operator-data sync.
+    #[serde(default, skip_serializing_if = "Option::is_none")]
+    pub sync: Option<DbSync>,
+}
+
+/// Where an install restored from this snapshot starts syncing.
+#[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
+pub struct DbSync {
+    /// The DHP database's sync id: an install only ever syncs with the database it came from.
+    pub db_id: String,
+    /// Oldest transaction still running when the snapshot was taken; the first pull starts there.
+    pub horizon: String,
 }
 
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]