store: Do not prune deployments that are being copied

Pruning during copying can cause the copy to fail because data it needs
disappears during copying.

Author: lutter

store/postgres/src/copy.rs

@@ -94,6 +94,20 @@ table! {
     }
 }
 
+/// Return `true` if the site is the source of a copy operation. The copy
+/// operation might be just queued or in progress already
+pub fn is_source(conn: &mut PgConnection, site: &Site) -> Result<bool, StoreError> {
+    use active_copies as ac;
+
+    select(diesel::dsl::exists(
+        ac::table
+            .filter(ac::src.eq(site.id))
+            .filter(ac::cancelled_at.is_null()),
+    ))
+    .get_result::<bool>(conn)
+    .map_err(StoreError::from)
+}
+
 #[derive(Copy, Clone, PartialEq, Eq)]
 pub enum Status {
     Finished,

store/postgres/src/deployment_store.rs

@@ -55,7 +55,7 @@ use crate::primary::DeploymentId;
 use crate::relational::index::{CreateIndex, IndexList, Method};
 use crate::relational::{Layout, LayoutCache, SqlName, Table};
 use crate::relational_queries::FromEntityData;
-use crate::{advisory_lock, catalog, retry};
+use crate::{advisory_lock, catalog, copy, retry};
 use crate::{connection_pool::ConnectionPool, detail};
 use crate::{dynds, primary::Site};
 
@@ -1234,6 +1234,14 @@ impl DeploymentStore {
             site: Arc<Site>,
             req: PruneRequest,
         ) -> Result<(), StoreError> {
+            let mut conn = store.get_conn()?;
+            if copy::is_source(&mut conn, &site)? {
+                debug!(
+                    logger,
+                    "Skipping pruning since this deployment is being copied"
+                );
+                return Ok(());
+            }
             let logger2 = logger.cheap_clone();
             retry::forever_async(&logger2, "prune", move || {
                 let store = store.cheap_clone();