frostfs-node/cmd/frostfs-cli/docs/storage-node-xheaders.md

Extended headers

Overview

Extended headers are used for request/response. They may contain any user-defined headers to be interpreted on application level. Key name must be a unique valid UTF-8 string. Value can't be empty. Requests or Responses with duplicated header names or headers with empty values are considered invalid.

Existing headers

There are some "well-known" headers starting with __SYSTEM__ prefix that affect system behaviour. For backward compatibility, the same set of "well-known" headers may also use __NEOFS__ prefix:

• __SYSTEM__NETMAP_EPOCH - netmap epoch to use for object placement calculation. The value is string encoded uint64 in decimal presentation. If set to '0' or omitted, the current epoch only will be used.
• __SYSTEM__NETMAP_LOOKUP_DEPTH - if object can't be found using current epoch's netmap, this header limits how many past epochs the node can look up through. Depth is applied to a current epoch or the value of __SYSTEM__NETMAP_EPOCH attribute. The value is string encoded uint64 in decimal presentation. If set to '0' or not set, only the current epoch is used.

frostfs-cli commands with --xhdr

List of commands with support of extended headers:

• container list-objects
• object delete/get/hash/head/lock/put/range/search

Example:

$ frostfs-cli object put -r s01.frostfs.devenv:8080 -w wallet.json --cid CID --file FILE --xhdr "__SYSTEM__NETMAP_EPOCH=777"