src/api2/backup.rs

   1 use failure::*;
   2 use futures::*;
   3 use hyper::header::{HeaderValue, UPGRADE};
   4 use hyper::http::request::Parts;
   5 use hyper::{Body, Response, StatusCode};
   6 use serde_json::{json, Value};
   7
   8 use proxmox::{sortable, identity};
   9 use proxmox::api::list_subdirs_api_method;
  10 use proxmox::api::{ApiFuture, ApiHandler, ApiMethod, Router, RpcEnvironment};
  11 use proxmox::api::router::SubdirMap;
  12 use proxmox::api::schema::*;
  13
  14 use crate::tools;
  15 use crate::tools::wrapped_reader_stream::*;
  16 use crate::server::{WorkerTask, H2Service};
  17 use crate::backup::*;
  18 use crate::api2::types::*;
  19
  20 mod environment;
  21 use environment::*;
  22
  23 mod upload_chunk;
  24 use upload_chunk::*;
  25
  26 pub const ROUTER: Router = Router::new()
  27     .upgrade(&API_METHOD_UPGRADE_BACKUP);
  28
  29 #[sortable]
  30 pub const API_METHOD_UPGRADE_BACKUP: ApiMethod = ApiMethod::new(
  31     &ApiHandler::Async(&upgrade_to_backup_protocol),
  32     &ObjectSchema::new(
  33         concat!("Upgraded to backup protocol ('", PROXMOX_BACKUP_PROTOCOL_ID_V1!(), "')."),
  34         &sorted!([
  35             ("store", false, &StringSchema::new("Datastore name.").schema()),
  36             ("backup-type", false, &BACKUP_TYPE_SCHEMA),
  37             ("backup-id", false, &BACKUP_ID_SCHEMA),
  38             ("backup-time", false, &BACKUP_TIME_SCHEMA),
  39             ("debug", true, &BooleanSchema::new("Enable verbose debug logging.").schema()),
  40         ]),
  41     )
  42 );
  43
  44 fn upgrade_to_backup_protocol(
  45     parts: Parts,
  46     req_body: Body,
  47     param: Value,
  48     _info: &ApiMethod,
  49     rpcenv: Box<dyn RpcEnvironment>,
  50 ) -> Result<ApiFuture, Error> {
  51
  52     let debug = param["debug"].as_bool().unwrap_or(false);
  53
  54     let store = tools::required_string_param(&param, "store")?.to_owned();
  55     let datastore = DataStore::lookup_datastore(&store)?;
  56
  57     let backup_type = tools::required_string_param(&param, "backup-type")?;
  58     let backup_id = tools::required_string_param(&param, "backup-id")?;
  59     let backup_time = tools::required_integer_param(&param, "backup-time")?;
  60
  61     let protocols = parts
  62         .headers
  63         .get("UPGRADE")
  64         .ok_or_else(|| format_err!("missing Upgrade header"))?
  65         .to_str()?;
  66
  67     if protocols != PROXMOX_BACKUP_PROTOCOL_ID_V1!() {
  68         bail!("invalid protocol name");
  69     }
  70
  71     if parts.version >=  http::version::Version::HTTP_2 {
  72         bail!("unexpected http version '{:?}' (expected version < 2)", parts.version);
  73     }
  74
  75     let worker_id = format!("{}_{}_{}", store, backup_type, backup_id);
  76
  77     let username = rpcenv.get_user().unwrap();
  78     let env_type = rpcenv.env_type();
  79
  80     let backup_group = BackupGroup::new(backup_type, backup_id);
  81     let last_backup = BackupInfo::last_backup(&datastore.base_path(), &backup_group).unwrap_or(None);
  82     let backup_dir = BackupDir::new_with_group(backup_group, backup_time);
  83
  84     if let Some(last) = &last_backup {
  85         if backup_dir.backup_time() <= last.backup_dir.backup_time() {
  86             bail!("backup timestamp is older than last backup.");
  87         }
  88     }
  89
  90     let (path, is_new) = datastore.create_backup_dir(&backup_dir)?;
  91     if !is_new { bail!("backup directorty already exists."); }
  92
  93     WorkerTask::spawn("backup", Some(worker_id), &username.clone(), true, move |worker| {
  94         let mut env = BackupEnvironment::new(
  95             env_type, username.clone(), worker.clone(), datastore, backup_dir);
  96
  97         env.debug = debug;
  98         env.last_backup = last_backup;
  99
 100         env.log(format!("starting new backup on datastore '{}': {:?}", store, path));
 101
 102         let service = H2Service::new(env.clone(), worker.clone(), &BACKUP_API_ROUTER, debug);
 103
 104         let abort_future = worker.abort_future();
 105
 106         let env2 = env.clone();
 107         let env3 = env.clone();
 108
 109         let req_fut = req_body
 110             .on_upgrade()
 111             .map_err(Error::from)
 112             .and_then(move |conn| {
 113                 env3.debug("protocol upgrade done");
 114
 115                 let mut http = hyper::server::conn::Http::new();
 116                 http.http2_only(true);
 117                 // increase window size: todo - find optiomal size
 118                 let window_size = 32*1024*1024; // max = (1 << 31) - 2
 119                 http.http2_initial_stream_window_size(window_size);
 120                 http.http2_initial_connection_window_size(window_size);
 121
 122                 http.serve_connection(conn, service)
 123                     .map_err(Error::from)
 124             });
 125         let abort_future = abort_future
 126             .map(|_| Err(format_err!("task aborted")));
 127
 128         use futures::future::Either;
 129         future::select(req_fut, abort_future)
 130             .map(|res| match res {
 131                 Either::Left((Ok(res), _)) => Ok(res),
 132                 Either::Left((Err(err), _)) => Err(err),
 133                 Either::Right((Ok(res), _)) => Ok(res),
 134                 Either::Right((Err(err), _)) => Err(err),
 135             })
 136             .and_then(move |_result| async move {
 137                 env.ensure_finished()?;
 138                 env.log("backup finished sucessfully");
 139                 Ok(())
 140             })
 141             .then(move |result| async move {
 142                 if let Err(err) = result {
 143                     match env2.ensure_finished() {
 144                         Ok(()) => {}, // ignore error after finish
 145                         _ => {
 146                             env2.log(format!("backup failed: {}", err));
 147                             env2.log("removing failed backup");
 148                             env2.remove_backup()?;
 149                             return Err(err);
 150                         }
 151                     }
 152                 }
 153                 Ok(())
 154             })
 155     })?;
 156
 157     let response = Response::builder()
 158         .status(StatusCode::SWITCHING_PROTOCOLS)
 159         .header(UPGRADE, HeaderValue::from_static(PROXMOX_BACKUP_PROTOCOL_ID_V1!()))
 160         .body(Body::empty())?;
 161
 162     Ok(Box::new(futures::future::ok(response)))
 163 }
 164
 165 pub const BACKUP_API_SUBDIRS: SubdirMap = &[
 166     (
 167         "blob", &Router::new()
 168             .upload(&API_METHOD_UPLOAD_BLOB)
 169     ),
 170     (
 171         "dynamic_chunk", &Router::new()
 172             .upload(&API_METHOD_UPLOAD_DYNAMIC_CHUNK)
 173     ),
 174     (
 175         "dynamic_close", &Router::new()
 176             .post(&API_METHOD_CLOSE_DYNAMIC_INDEX)
 177     ),
 178     (
 179         "dynamic_index", &Router::new()
 180             .download(&API_METHOD_DYNAMIC_CHUNK_INDEX)
 181             .post(&API_METHOD_CREATE_DYNAMIC_INDEX)
 182             .put(&API_METHOD_DYNAMIC_APPEND)
 183     ),
 184     (
 185         "finish", &Router::new()
 186             .post(
 187                 &ApiMethod::new(
 188                     &ApiHandler::Sync(&finish_backup),
 189                     &ObjectSchema::new("Mark backup as finished.", &[])
 190                 )
 191             )
 192     ),
 193     (
 194         "fixed_chunk", &Router::new()
 195             .upload(&API_METHOD_UPLOAD_FIXED_CHUNK)
 196     ),
 197     (
 198         "fixed_close", &Router::new()
 199             .post(&API_METHOD_CLOSE_FIXED_INDEX)
 200     ),
 201     (
 202         "fixed_index", &Router::new()
 203             .download(&API_METHOD_FIXED_CHUNK_INDEX)
 204             .post(&API_METHOD_CREATE_FIXED_INDEX)
 205             .put(&API_METHOD_FIXED_APPEND)
 206     ),
 207     (
 208         "speedtest", &Router::new()
 209             .upload(&API_METHOD_UPLOAD_SPEEDTEST)
 210     ),
 211 ];
 212
 213 pub const BACKUP_API_ROUTER: Router = Router::new()
 214     .get(&list_subdirs_api_method!(BACKUP_API_SUBDIRS))
 215     .subdirs(BACKUP_API_SUBDIRS);
 216
 217 #[sortable]
 218 pub const API_METHOD_CREATE_DYNAMIC_INDEX: ApiMethod = ApiMethod::new(
 219     &ApiHandler::Sync(&create_dynamic_index),
 220     &ObjectSchema::new(
 221         "Create dynamic chunk index file.",
 222         &sorted!([
 223             ("archive-name", false, &crate::api2::types::BACKUP_ARCHIVE_NAME_SCHEMA),
 224         ]),
 225     )
 226 );
 227
 228 fn create_dynamic_index(
 229     param: Value,
 230     _info: &ApiMethod,
 231     rpcenv: &mut dyn RpcEnvironment,
 232 ) -> Result<Value, Error> {
 233
 234     let env: &BackupEnvironment = rpcenv.as_ref();
 235
 236     let name = tools::required_string_param(&param, "archive-name")?.to_owned();
 237
 238     let archive_name = name.clone();
 239     if !archive_name.ends_with(".didx") {
 240         bail!("wrong archive extension: '{}'", archive_name);
 241     }
 242
 243     let mut path = env.backup_dir.relative_path();
 244     path.push(archive_name);
 245
 246     let index = env.datastore.create_dynamic_writer(&path)?;
 247     let wid = env.register_dynamic_writer(index, name)?;
 248
 249     env.log(format!("created new dynamic index {} ({:?})", wid, path));
 250
 251     Ok(json!(wid))
 252 }
 253
 254 #[sortable]
 255 pub const API_METHOD_CREATE_FIXED_INDEX: ApiMethod = ApiMethod::new(
 256     &ApiHandler::Sync(&create_fixed_index),
 257     &ObjectSchema::new(
 258         "Create fixed chunk index file.",
 259         &sorted!([
 260             ("archive-name", false, &crate::api2::types::BACKUP_ARCHIVE_NAME_SCHEMA),
 261             ("size", false, &IntegerSchema::new("File size.")
 262              .minimum(1)
 263              .schema()
 264             ),
 265         ]),
 266     )
 267 );
 268
 269 fn create_fixed_index(
 270     param: Value,
 271     _info: &ApiMethod,
 272     rpcenv: &mut dyn RpcEnvironment,
 273 ) -> Result<Value, Error> {
 274
 275     let env: &BackupEnvironment = rpcenv.as_ref();
 276
 277     println!("PARAM: {:?}", param);
 278
 279     let name = tools::required_string_param(&param, "archive-name")?.to_owned();
 280     let size = tools::required_integer_param(&param, "size")? as usize;
 281
 282     let archive_name = name.clone();
 283     if !archive_name.ends_with(".fidx") {
 284         bail!("wrong archive extension: '{}'", archive_name);
 285     }
 286
 287     let mut path = env.backup_dir.relative_path();
 288     path.push(archive_name);
 289
 290     let chunk_size = 4096*1024; // todo: ??
 291
 292     let index = env.datastore.create_fixed_writer(&path, size, chunk_size)?;
 293     let wid = env.register_fixed_writer(index, name, size, chunk_size as u32)?;
 294
 295     env.log(format!("created new fixed index {} ({:?})", wid, path));
 296
 297     Ok(json!(wid))
 298 }
 299
 300 #[sortable]
 301 pub const API_METHOD_DYNAMIC_APPEND: ApiMethod = ApiMethod::new(
 302     &ApiHandler::Sync(&dynamic_append),
 303     &ObjectSchema::new(
 304         "Append chunk to dynamic index writer.",
 305         &sorted!([
 306             (
 307                 "wid",
 308                 false,
 309                 &IntegerSchema::new("Dynamic writer ID.")
 310                     .minimum(1)
 311                     .maximum(256)
 312                     .schema()
 313             ),
 314             (
 315                 "digest-list",
 316                 false,
 317                 &ArraySchema::new("Chunk digest list.", &CHUNK_DIGEST_SCHEMA).schema()
 318             ),
 319             (
 320                 "offset-list",
 321                 false,
 322                 &ArraySchema::new(
 323                     "Chunk offset list.",
 324                     &IntegerSchema::new("Corresponding chunk offsets.")
 325                         .minimum(0)
 326                         .schema()
 327                 ).schema()
 328             ),
 329         ]),
 330     )
 331 );
 332
 333 fn dynamic_append (
 334     param: Value,
 335     _info: &ApiMethod,
 336     rpcenv: &mut dyn RpcEnvironment,
 337 ) -> Result<Value, Error> {
 338
 339     let wid = tools::required_integer_param(&param, "wid")? as usize;
 340     let digest_list = tools::required_array_param(&param, "digest-list")?;
 341     let offset_list = tools::required_array_param(&param, "offset-list")?;
 342
 343     if offset_list.len() != digest_list.len() {
 344         bail!("offset list has wrong length ({} != {})", offset_list.len(), digest_list.len());
 345     }
 346
 347     let env: &BackupEnvironment = rpcenv.as_ref();
 348
 349     env.debug(format!("dynamic_append {} chunks", digest_list.len()));
 350
 351     for (i, item) in digest_list.iter().enumerate() {
 352         let digest_str = item.as_str().unwrap();
 353         let digest = proxmox::tools::hex_to_digest(digest_str)?;
 354         let offset = offset_list[i].as_u64().unwrap();
 355         let size = env.lookup_chunk(&digest).ok_or_else(|| format_err!("no such chunk {}", digest_str))?;
 356
 357         env.dynamic_writer_append_chunk(wid, offset, size, &digest)?;
 358
 359         env.debug(format!("sucessfully added chunk {} to dynamic index {} (offset {}, size {})", digest_str, wid, offset, size));
 360     }
 361
 362     Ok(Value::Null)
 363 }
 364
 365 #[sortable]
 366 pub const API_METHOD_FIXED_APPEND: ApiMethod = ApiMethod::new(
 367     &ApiHandler::Sync(&fixed_append),
 368     &ObjectSchema::new(
 369         "Append chunk to fixed index writer.",
 370         &sorted!([
 371             (
 372                 "wid",
 373                 false,
 374                 &IntegerSchema::new("Fixed writer ID.")
 375                     .minimum(1)
 376                     .maximum(256)
 377                     .schema()
 378             ),
 379             (
 380                 "digest-list",
 381                 false,
 382                 &ArraySchema::new("Chunk digest list.", &CHUNK_DIGEST_SCHEMA).schema()
 383             ),
 384             (
 385                 "offset-list",
 386                 false,
 387                 &ArraySchema::new(
 388                     "Chunk offset list.",
 389                     &IntegerSchema::new("Corresponding chunk offsets.")
 390                         .minimum(0)
 391                         .schema()
 392                 ).schema()
 393             )
 394         ]),
 395     )
 396 );
 397
 398 fn fixed_append (
 399     param: Value,
 400     _info: &ApiMethod,
 401     rpcenv: &mut dyn RpcEnvironment,
 402 ) -> Result<Value, Error> {
 403
 404     let wid = tools::required_integer_param(&param, "wid")? as usize;
 405     let digest_list = tools::required_array_param(&param, "digest-list")?;
 406     let offset_list = tools::required_array_param(&param, "offset-list")?;
 407
 408     if offset_list.len() != digest_list.len() {
 409         bail!("offset list has wrong length ({} != {})", offset_list.len(), digest_list.len());
 410     }
 411
 412     let env: &BackupEnvironment = rpcenv.as_ref();
 413
 414     env.debug(format!("fixed_append {} chunks", digest_list.len()));
 415
 416     for (i, item) in digest_list.iter().enumerate() {
 417         let digest_str = item.as_str().unwrap();
 418         let digest = proxmox::tools::hex_to_digest(digest_str)?;
 419         let offset = offset_list[i].as_u64().unwrap();
 420         let size = env.lookup_chunk(&digest).ok_or_else(|| format_err!("no such chunk {}", digest_str))?;
 421
 422         env.fixed_writer_append_chunk(wid, offset, size, &digest)?;
 423
 424         env.debug(format!("sucessfully added chunk {} to fixed index {} (offset {}, size {})", digest_str, wid, offset, size));
 425     }
 426
 427     Ok(Value::Null)
 428 }
 429
 430 #[sortable]
 431 pub const API_METHOD_CLOSE_DYNAMIC_INDEX: ApiMethod = ApiMethod::new(
 432     &ApiHandler::Sync(&close_dynamic_index),
 433     &ObjectSchema::new(
 434         "Close dynamic index writer.",
 435         &sorted!([
 436             (
 437                 "wid",
 438                 false,
 439                 &IntegerSchema::new("Dynamic writer ID.")
 440                     .minimum(1)
 441                     .maximum(256)
 442                     .schema()
 443             ),
 444             (
 445                 "chunk-count",
 446                 false,
 447                 &IntegerSchema::new("Chunk count. This is used to verify that the server got all chunks.")
 448                     .minimum(1)
 449                     .schema()
 450             ),
 451             (
 452                 "size",
 453                 false,
 454                 &IntegerSchema::new("File size. This is used to verify that the server got all data.")
 455                     .minimum(1)
 456                     .schema()
 457             ),
 458             ("csum", false, &StringSchema::new("Digest list checksum.").schema()),
 459         ]),
 460     )
 461 );
 462
 463 fn close_dynamic_index (
 464     param: Value,
 465     _info: &ApiMethod,
 466     rpcenv: &mut dyn RpcEnvironment,
 467 ) -> Result<Value, Error> {
 468
 469     let wid = tools::required_integer_param(&param, "wid")? as usize;
 470     let chunk_count = tools::required_integer_param(&param, "chunk-count")? as u64;
 471     let size = tools::required_integer_param(&param, "size")? as u64;
 472     let csum_str = tools::required_string_param(&param, "csum")?;
 473     let csum = proxmox::tools::hex_to_digest(csum_str)?;
 474
 475     let env: &BackupEnvironment = rpcenv.as_ref();
 476
 477     env.dynamic_writer_close(wid, chunk_count, size, csum)?;
 478
 479     env.log(format!("sucessfully closed dynamic index {}", wid));
 480
 481     Ok(Value::Null)
 482 }
 483
 484 #[sortable]
 485 pub const API_METHOD_CLOSE_FIXED_INDEX: ApiMethod = ApiMethod::new(
 486     &ApiHandler::Sync(&close_fixed_index),
 487     &ObjectSchema::new(
 488         "Close fixed index writer.",
 489         &sorted!([
 490             (
 491                 "wid",
 492                 false,
 493                 &IntegerSchema::new("Fixed writer ID.")
 494                     .minimum(1)
 495                     .maximum(256)
 496                     .schema()
 497             ),
 498             (
 499                 "chunk-count",
 500                 false,
 501                 &IntegerSchema::new("Chunk count. This is used to verify that the server got all chunks.")
 502                     .minimum(1)
 503                     .schema()
 504             ),
 505             (
 506                 "size",
 507                 false,
 508                 &IntegerSchema::new("File size. This is used to verify that the server got all data.")
 509                     .minimum(1)
 510                     .schema()
 511             ),
 512             ("csum", false, &StringSchema::new("Digest list checksum.").schema()),
 513         ]),
 514     )
 515 );
 516
 517 fn close_fixed_index (
 518     param: Value,
 519     _info: &ApiMethod,
 520     rpcenv: &mut dyn RpcEnvironment,
 521 ) -> Result<Value, Error> {
 522
 523     let wid = tools::required_integer_param(&param, "wid")? as usize;
 524     let chunk_count = tools::required_integer_param(&param, "chunk-count")? as u64;
 525     let size = tools::required_integer_param(&param, "size")? as u64;
 526     let csum_str = tools::required_string_param(&param, "csum")?;
 527     let csum = proxmox::tools::hex_to_digest(csum_str)?;
 528
 529     let env: &BackupEnvironment = rpcenv.as_ref();
 530
 531     env.fixed_writer_close(wid, chunk_count, size, csum)?;
 532
 533     env.log(format!("sucessfully closed fixed index {}", wid));
 534
 535     Ok(Value::Null)
 536 }
 537
 538 fn finish_backup (
 539     _param: Value,
 540     _info: &ApiMethod,
 541     rpcenv: &mut dyn RpcEnvironment,
 542 ) -> Result<Value, Error> {
 543
 544     let env: &BackupEnvironment = rpcenv.as_ref();
 545
 546     env.finish_backup()?;
 547     env.log("sucessfully finished backup");
 548
 549     Ok(Value::Null)
 550 }
 551
 552 #[sortable]
 553 pub const API_METHOD_DYNAMIC_CHUNK_INDEX: ApiMethod = ApiMethod::new(
 554     &ApiHandler::Async(&dynamic_chunk_index),
 555     &ObjectSchema::new(
 556         r###"
 557 Download the dynamic chunk index from the previous backup.
 558 Simply returns an empty list if this is the first backup.
 559 "### ,
 560         &sorted!([
 561             ("archive-name", false, &crate::api2::types::BACKUP_ARCHIVE_NAME_SCHEMA)
 562         ]),
 563     )
 564 );
 565
 566 fn dynamic_chunk_index(
 567     _parts: Parts,
 568     _req_body: Body,
 569     param: Value,
 570     _info: &ApiMethod,
 571     rpcenv: Box<dyn RpcEnvironment>,
 572 ) -> Result<ApiFuture, Error> {
 573
 574     let env: &BackupEnvironment = rpcenv.as_ref();
 575
 576     let archive_name = tools::required_string_param(&param, "archive-name")?.to_owned();
 577
 578     if !archive_name.ends_with(".didx") {
 579         bail!("wrong archive extension: '{}'", archive_name);
 580     }
 581
 582     let empty_response = {
 583         Response::builder()
 584             .status(StatusCode::OK)
 585             .body(Body::empty())?
 586     };
 587
 588     let last_backup = match &env.last_backup {
 589         Some(info) => info,
 590         None => return Ok(Box::new(future::ok(empty_response))),
 591     };
 592
 593     let mut path = last_backup.backup_dir.relative_path();
 594     path.push(&archive_name);
 595
 596     let index = match env.datastore.open_dynamic_reader(path) {
 597         Ok(index) => index,
 598         Err(_) => {
 599             env.log(format!("there is no last backup for archive '{}'", archive_name));
 600             return Ok(Box::new(future::ok(empty_response)));
 601         }
 602     };
 603
 604     env.log(format!("download last backup index for archive '{}'", archive_name));
 605
 606     let count = index.index_count();
 607     for pos in 0..count {
 608         let (start, end, digest) = index.chunk_info(pos)?;
 609         let size = (end - start) as u32;
 610         env.register_chunk(digest, size)?;
 611     }
 612
 613     let reader = DigestListEncoder::new(Box::new(index));
 614
 615     let stream = WrappedReaderStream::new(reader);
 616
 617     // fixme: set size, content type?
 618     let response = http::Response::builder()
 619         .status(200)
 620         .body(Body::wrap_stream(stream))?;
 621
 622     Ok(Box::new(future::ok(response)))
 623 }
 624
 625 #[sortable]
 626 pub const API_METHOD_FIXED_CHUNK_INDEX: ApiMethod = ApiMethod::new(
 627     &ApiHandler::Async(&fixed_chunk_index),
 628     &ObjectSchema::new(
 629         r###"
 630 Download the fixed chunk index from the previous backup.
 631 Simply returns an empty list if this is the first backup.
 632 "### ,
 633         &sorted!([
 634             ("archive-name", false, &crate::api2::types::BACKUP_ARCHIVE_NAME_SCHEMA)
 635         ]),
 636     )
 637 );
 638
 639 fn fixed_chunk_index(
 640     _parts: Parts,
 641     _req_body: Body,
 642     param: Value,
 643     _info: &ApiMethod,
 644     rpcenv: Box<dyn RpcEnvironment>,
 645 ) -> Result<ApiFuture, Error> {
 646
 647     let env: &BackupEnvironment = rpcenv.as_ref();
 648
 649     let archive_name = tools::required_string_param(&param, "archive-name")?.to_owned();
 650
 651     if !archive_name.ends_with(".fidx") {
 652         bail!("wrong archive extension: '{}'", archive_name);
 653     }
 654
 655     let empty_response = {
 656         Response::builder()
 657             .status(StatusCode::OK)
 658             .body(Body::empty())?
 659     };
 660
 661     let last_backup = match &env.last_backup {
 662         Some(info) => info,
 663         None => return Ok(Box::new(future::ok(empty_response))),
 664     };
 665
 666     let mut path = last_backup.backup_dir.relative_path();
 667     path.push(&archive_name);
 668
 669     let index = match env.datastore.open_fixed_reader(path) {
 670         Ok(index) => index,
 671         Err(_) => {
 672             env.log(format!("there is no last backup for archive '{}'", archive_name));
 673             return Ok(Box::new(future::ok(empty_response)));
 674         }
 675     };
 676
 677     env.log(format!("download last backup index for archive '{}'", archive_name));
 678
 679     let count = index.index_count();
 680     let image_size = index.index_bytes();
 681     for pos in 0..count {
 682         let digest = index.index_digest(pos).unwrap();
 683         // Note: last chunk can be smaller
 684         let start = (pos*index.chunk_size) as u64;
 685         let mut end = start + index.chunk_size as u64;
 686         if end > image_size { end = image_size; }
 687         let size = (end - start) as u32;
 688         env.register_chunk(*digest, size)?;
 689     }
 690
 691     let reader = DigestListEncoder::new(Box::new(index));
 692
 693     let stream = WrappedReaderStream::new(reader);
 694
 695     // fixme: set size, content type?
 696     let response = http::Response::builder()
 697         .status(200)
 698         .body(Body::wrap_stream(stream))?;
 699
 700     Ok(Box::new(future::ok(response)))
 701 }