[pbs-devel] [RFC proxmox-backup 16/24] server: sync: factor out namespace depth check into sync module

[Christian Ebner]

By moving and refactoring the check for a sync job exceeding the
global maximum namespace limit, the same function can be reused for
sync jobs in push direction.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
 src/server/pull.rs | 20 +++-----------------
 src/server/sync.rs | 21 +++++++++++++++++++++
 2 files changed, 24 insertions(+), 17 deletions(-)

diff --git a/src/server/pull.rs b/src/server/pull.rs
index d18c6d643..3117f7d2c 100644
--- a/src/server/pull.rs
+++ b/src/server/pull.rs
@@ -28,8 +28,8 @@ use pbs_datastore::{check_backup_owner, DataStore, StoreProgress};
 use pbs_tools::sha::sha256;
 
 use super::sync::{
-    LocalSource, RemoteSource, RemovedVanishedStats, SkipInfo, SkipReason, SyncSource,
-    SyncSourceReader, SyncStats,
+    check_namespace_depth_limit, LocalSource, RemoteSource, RemovedVanishedStats, SkipInfo,
+    SkipReason, SyncSource, SyncSourceReader, SyncStats,
 };
 use crate::backup::{check_ns_modification_privs, check_ns_privs};
 use crate::tools::parallel_handler::ParallelHandler;
@@ -735,21 +735,7 @@ pub(crate) async fn pull_store(mut params: PullParameters) -> Result<SyncStats,
         params.source.list_namespaces(&mut params.max_depth).await?
     };
 
-    let ns_layers_to_be_pulled = namespaces
-        .iter()
-        .map(BackupNamespace::depth)
-        .max()
-        .map_or(0, |v| v - params.source.get_ns().depth());
-    let target_depth = params.target.ns.depth();
-
-    if ns_layers_to_be_pulled + target_depth > MAX_NAMESPACE_DEPTH {
-        bail!(
-            "Syncing would exceed max allowed namespace depth. ({}+{} > {})",
-            ns_layers_to_be_pulled,
-            target_depth,
-            MAX_NAMESPACE_DEPTH
-        );
-    }
+    check_namespace_depth_limit(&params.source.get_ns(), &params.target.ns, &namespaces)?;
 
     errors |= old_max_depth != params.max_depth; // fail job if we switched to backwards-compat mode
     namespaces.sort_unstable_by_key(|a| a.name_len());
diff --git a/src/server/sync.rs b/src/server/sync.rs
index ee40d0b9d..bd68dda46 100644
--- a/src/server/sync.rs
+++ b/src/server/sync.rs
@@ -547,3 +547,24 @@ impl std::fmt::Display for SkipInfo {
         )
     }
 }
+
+/// Check if a sync from source to target of given namespaces exceeds the global namespace depth limit
+pub(crate) fn check_namespace_depth_limit(
+    source_namespace: &BackupNamespace,
+    target_namespace: &BackupNamespace,
+    namespaces: &[BackupNamespace],
+) -> Result<(), Error> {
+    let target_ns_depth = target_namespace.depth();
+    let sync_ns_depth = namespaces
+        .iter()
+        .map(BackupNamespace::depth)
+        .max()
+        .map_or(0, |v| v - source_namespace.depth());
+
+    if sync_ns_depth + target_ns_depth > MAX_NAMESPACE_DEPTH {
+        bail!(
+            "Syncing would exceed max allowed namespace depth. ({sync_ns_depth}+{target_ns_depth} > {MAX_NAMESPACE_DEPTH})",
+        );
+    }
+    Ok(())
+}
-- 
2.39.2