[pbs-devel] [PATCH proxmox-backup] api: backup: include previous snapshot name in log message

[Christian Ebner]

Extends the log messages written to the server's backup worker task
log to include the snapshot name which is used as previous snapshot.

This information facilitates debugging efforts, as the previous
snapshot might have been pruned since.

For example, instead of
```
download 'index.json.blob' from previous backup.
register chunks in 'drive-scsi0.img.fidx' from previous backup.
download 'drive-scsi0.img.fidx' from previous backup.
```

this now logs
```
download 'index.json.blob' from previous backup 'vm/101/2025-04-15T09:02:10Z'.
register chunks in 'drive-scsi0.img.fidx' from previous backup 'vm/101/2025-04-15T09:02:10Z'.
download 'drive-scsi0.img.fidx' from previous backup 'vm/101/2025-04-15T09:02:10Z'.
```

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
This information is of great interest when debugging issues like, e.g.
https://my.proxmox.com/en/dbsfk/ticket/view/17530

 src/api2/backup/mod.rs | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/src/api2/backup/mod.rs b/src/api2/backup/mod.rs
index 344c80d46..629df933e 100644
--- a/src/api2/backup/mod.rs
+++ b/src/api2/backup/mod.rs
@@ -853,8 +853,8 @@ fn download_previous(
             };
             if let Some(index) = index {
                 env.log(format!(
-                    "register chunks in '{}' from previous backup.",
-                    archive_name
+                    "register chunks in '{archive_name}' from previous backup '{}'.",
+                    last_backup.backup_dir.dir(),
                 ));
 
                 for pos in 0..index.index_count() {
@@ -865,7 +865,10 @@ fn download_previous(
             }
         }
 
-        env.log(format!("download '{}' from previous backup.", archive_name));
+        env.log(format!(
+            "download '{archive_name}' from previous backup '{}'.",
+            last_backup.backup_dir.dir(),
+        ));
         crate::api2::helpers::create_download_response(path).await
     }
     .boxed()
-- 
2.39.5