Module codec 

Available on crate feature alloc only.

Stable binary codec for serialising audit records to bytes.

Requires the alloc feature. std-gated readers and sinks (crate::FileSink, crate::FileReader) use this codec under the hood.

Stability promise

The byte layout defined here is stable. Changing it is a breaking change to any on-disk audit log. The format embeds a one-byte version (FORMAT_VERSION) so future incompatible formats can coexist by bumping it.

File layout

┌────────────────────────────────────────────────────────────────┐
│ FILE HEADER (16 bytes)                                         │
├────────────────────────────────────────────────────────────────┤
│ 0..8   "AUDTRAIL" magic                                        │
│ 8      format version (currently 0x01)                         │
│ 9..16  reserved, zero                                          │
├────────────────────────────────────────────────────────────────┤
│ RECORD FRAME (one per record, repeated)                        │
├────────────────────────────────────────────────────────────────┤
│ 0..4   record body length (u32 big-endian)                     │
│ 4..    record body                                             │
└────────────────────────────────────────────────────────────────┘

Record body layout

0..8    id           u64 big-endian
8..16   timestamp    u64 big-endian (nanoseconds since Unix epoch)
16      outcome      u8
17..49  prev_hash    32 bytes
49..81  hash         32 bytes
81..85  actor_len    u32 big-endian
85..    actor        UTF-8 bytes
...     action_len   u32 big-endian
...     action       UTF-8 bytes
...     target_len   u32 big-endian
...     target       UTF-8 bytes

Constants

FILE_HEADER_LEN

Length of the file header in bytes.

FORMAT_MAGIC

File-format magic bytes. Appear at the start of every chain file.

FORMAT_VERSION

Current file-format version.

Functions

decode_record

Decode a single length-prefixed record frame from the front of bytes. Returns the decoded record plus the number of bytes consumed.

encode_record

Encode record into a length-prefixed frame appended to out.

verify_file_header

Verify that bytes begins with a valid file header.

write_file_header

Write the file header into out.