Module location

Abstractions over files, cloud storage, etc used in persistence.

Structs

• BlobMetadata
  Metadata about a particular blob stored by persist
• Determinate
  An error coming from an underlying durability system (e.g. s3) indicating that the operation definitely did NOT succeed (e.g. permission denied).
• Indeterminate
  An error coming from an underlying durability system (e.g. s3) indicating that the operation might have succeeded (e.g. timeout).
• SeqNo
  The “sequence number” of a persist state change.
• Tasked
  Wraps all calls to a backing store in a new tokio task. This adds extra overhead, but insulates the system from callers who fail to drive futures promptly to completion, which can cause timeouts or resource exhaustion in a store.
• VersionedData
  An abstraction for a single arbitrarily-sized binary blob and an associated version number (sequence number).

Enums

• CaSResult
  Return type to indicate whether Consensus::compare_and_set succeeded or failed.
• ExternalError
  An error coming from an underlying durability system (e.g. s3) or from invalid data received from one.

Constants

• BLOB_GET_LIVENESS_KEY
  A key usable for liveness checks via Blob::get.
• CONSENSUS_HEAD_LIVENESS_KEY
  A key usable for liveness checks via Consensus::head.
• SCAN_ALL
  Helper constant to scan all states in Consensus::scan. The maximum possible SeqNo is i64::MAX.

Traits

• Blob
  An abstraction over read-write access to a bytes key->bytes value store.
• Consensus
  An abstraction for VersionedData held in a location in persistent storage where the data are conditionally updated by version.

Type Aliases

• ResultStream
  A boxed stream, similar to what async_trait desugars async functions to, but hardcoded to our standard result type.