[pbs-devel] [PATCH proxmox-backup 4/5] proxmox-backup-client: restore: add 'ignore-extract-device-errors' flag

[Max Carrara <m.carrara@proxmox.com>]

If this flag is provided, any errors that occur during the extraction
of a device node are silently ignored.

In addition to this flag and its error handler, the bare scaffold
for supporting multiple error handlers is also added.

Signed-off-by: Max Carrara <m.carrara@proxmox.com>
---

Notes:
  One thing I'm not *really* sure about here is the name of the CLI
  flag - to me it feels a little bit too verbose, but it does exactly
  what it says.

 proxmox-backup-client/src/main.rs | 61 ++++++++++++++++++++++++++++++-
 1 file changed, 60 insertions(+), 1 deletion(-)

diff --git a/proxmox-backup-client/src/main.rs b/proxmox-backup-client/src/main.rs
index 55198108..1fb8a378 100644
--- a/proxmox-backup-client/src/main.rs
+++ b/proxmox-backup-client/src/main.rs
@@ -29,6 +29,7 @@ use pbs_api_types::{
     BACKUP_TYPE_SCHEMA, TRAFFIC_CONTROL_BURST_SCHEMA, TRAFFIC_CONTROL_RATE_SCHEMA,
 };
 use pbs_client::catalog_shell::Shell;
+use pbs_client::pxar::ErrorHandler as PxarErrorHandler;
 use pbs_client::tools::{
     complete_archive_name, complete_auth_id, complete_backup_group, complete_backup_snapshot,
     complete_backup_source, complete_chunk_size, complete_group_or_snapshot,
@@ -1232,6 +1233,12 @@ We do not extract '.pxar' archives when writing to standard output.
                 optional: true,
                 default: false,
             },
+            "ignore-extract-device-errors": {
+                type: Boolean,
+                description: "ignore errors that occur during device node extraction",
+                optional: true,
+                default: false,
+            }
         }
     }
 )]
@@ -1244,6 +1251,7 @@ async fn restore(
     ignore_ownership: bool,
     ignore_permissions: bool,
     overwrite: bool,
+    ignore_extract_device_errors: bool,
 ) -> Result<Value, Error> {
     let repo = extract_repository_from_value(&param)?;
 
@@ -1364,12 +1372,63 @@ async fn restore(
 
         let mut reader = BufferedDynamicReader::new(index, chunk_reader);
 
+        fn make_handler_from_many<I>(handlers: I) -> PxarErrorHandler
+        where
+            I: IntoIterator<Item = PxarErrorHandler>,
+        {
+            let mut captured_handlers: Vec<PxarErrorHandler> = handlers.into_iter().collect();
+
+            let handler: PxarErrorHandler = Box::new(move |error: Error| -> Result<(), Error> {
+                let mut res = Err(error);
+
+                for handler in captured_handlers.iter_mut() {
+                    if let Err(error) = res {
+                        res = handler(error);
+                    } else {
+                        return res;
+                    }
+                }
+
+                res
+            });
+
+            handler
+        }
+
+        let mut handlers: Vec<PxarErrorHandler> = Vec::new();
+
+        if ignore_extract_device_errors {
+            let on_device_error = Box::new(move |err: Error| {
+                use pbs_client::pxar::PxarExtractContext;
+
+                let ctx = err.downcast_ref::<PxarExtractContext>();
+
+                if ctx.is_none() {
+                    return Err(err);
+                }
+
+                if matches!(ctx.unwrap(), PxarExtractContext::ExtractDevice) {
+                    return Ok(());
+                }
+
+                Err(err)
+            });
+
+            handlers.push(on_device_error);
+        }
+
+        let on_error = if handlers.is_empty() {
+            None
+        } else {
+            Some(make_handler_from_many(handlers))
+        };
+
         let options = pbs_client::pxar::PxarExtractOptions {
             match_list: &[],
             extract_match_default: true,
             allow_existing_dirs,
             overwrite,
-            on_error: None,
+            on_error,
         };
 
         let mut feature_flags = pbs_client::pxar::Flags::DEFAULT;
-- 
2.30.2