[pbs-devel] [RFC proxmox-backup 18/39] api: backup: conditionally upload indices to S3 object store backend

[Christian Ebner]

If the datastore is backed by an S3 compatible object store, upload
the dynamic or fixed index files to the object store after closing
them. The local index files are kept in the local caching datastore
to allow for fast and efficient content lookups, avoiding expensive
(as in monetary cost and IO latency) requests.

Signed-off-by: Christian Ebner <c.ebner at proxmox.com>
---
 src/api2/backup/environment.rs | 65 ++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)

diff --git a/src/api2/backup/environment.rs b/src/api2/backup/environment.rs
index 393a8351d..72e369bcf 100644
--- a/src/api2/backup/environment.rs
+++ b/src/api2/backup/environment.rs
@@ -2,6 +2,7 @@ use anyhow::{bail, format_err, Context, Error};
 use pbs_config::BackupLockGuard;
 
 use std::collections::HashMap;
+use std::io::Read;
 use std::sync::{Arc, Mutex};
 use tracing::info;
 
@@ -479,6 +480,38 @@ impl BackupEnvironment {
             );
         }
 
+        // For S3 backends, upload the index file to the object store after closing
+        if let DatastoreBackend::S3(s3_client) = &self.backend {
+            let mut object_key = self.backup_dir.relative_path();
+            object_key.push(&data.name);
+            let object_key = object_key
+                .as_os_str()
+                .to_str()
+                .ok_or_else(|| format_err!("invalid file name"))?;
+
+            let mut full_path = self.datastore.base_path();
+            full_path.push(object_key);
+            let mut file = std::fs::File::open(&full_path)?;
+            let mut buffer = Vec::new();
+            file.read_to_end(&mut buffer)?;
+            let data = Body::from(buffer);
+            match proxmox_async::runtime::block_on(s3_client.put_object(object_key.into(), data))? {
+                PutObjectResponse::PreconditionFailed => {
+                    self.log(format!(
+                        "Upload of dynamic index failed, object key {object_key} already present"
+                    ));
+                    bail!("Upload of dynamic index failed");
+                }
+                PutObjectResponse::NeedsRetry => {
+                    self.log("Upload of dynamic index failed, reupload required");
+                    bail!("concurrent operation, reupload required");
+                }
+                PutObjectResponse::Success(_content) => {
+                    self.log(format!("Uploaded index file to object store: {object_key}"))
+                }
+            }
+        }
+
         self.log_upload_stat(
             &data.name,
             &csum,
@@ -553,6 +586,38 @@ impl BackupEnvironment {
             );
         }
 
+        // For S3 backends, upload the index file to the object store after closing
+        if let DatastoreBackend::S3(s3_client) = &self.backend {
+            let mut object_key = self.backup_dir.relative_path();
+            object_key.push(&data.name);
+            let object_key = object_key
+                .as_os_str()
+                .to_str()
+                .ok_or_else(|| format_err!("invalid file name"))?;
+
+            let mut full_path = self.datastore.base_path();
+            full_path.push(object_key);
+            let mut file = std::fs::File::open(&full_path)?;
+            let mut buffer = Vec::new();
+            file.read_to_end(&mut buffer)?;
+            let data = Body::from(buffer);
+            match proxmox_async::runtime::block_on(s3_client.put_object(object_key.into(), data))? {
+                PutObjectResponse::PreconditionFailed => {
+                    self.log(format!(
+                        "Upload of fixed index failed, object {object_key} already present."
+                    ));
+                    bail!("upload of fixed index failed");
+                }
+                PutObjectResponse::NeedsRetry => {
+                    self.log("Upload of fixed index failed, reupload required.");
+                    bail!("concurrent operation, reupload required");
+                }
+                PutObjectResponse::Success(_content) => {
+                    self.log(format!("Uploaded index file to object store: {object_key}"))
+                }
+            }
+        }
+
         self.log_upload_stat(
             &data.name,
             &expected_csum,
-- 
2.39.5