Struct WalChangeCapture 

pub struct WalChangeCapture { /* private fields */ }

Postgres change capture over logical replication (pgoutput).

Exposes the two ChangeCapture capabilities the engine orchestrates:

• live connects to a replication slot and streams committed row changes as thin Changes. Resume is the slot’s: its confirmed_flush_lsn is the durable cursor on the server, advanced as the engine confirms changes (see Ack).
• snapshot reads current rows over an ordinary SQL connection for an initial backfill (see the crate-private backfill). The engine calls it only for tables backing an index the sink reports as unseeded.

Prerequisites

The server must have wal_level = logical. The replication slot is created automatically on first connect if it does not exist yet, and the publication is created/extended to cover every table any index reads — see CaptureProvisioning — when the role is privileged enough and management is not opted out; otherwise flusso warns with the SQL to run.

Implementations

impl WalChangeCapture

pub fn new(config: ReplicationConfig, connection_url: impl Into<String>) -> Self

Create a capture from a pgwire-replication configuration and the ordinary SQL connection URL the snapshot reads through (the same URL the document builder connects with).

Leave config.start_lsn at Lsn::ZERO to resume from the slot’s confirmed_flush_lsn — the usual choice.

pub fn with_publication_management( self, required: BTreeSet<QualifiedTable>, manage: bool, ) -> Self

Declare the tables the publication must cover and whether to provision the gap automatically on live. required is typically SourceSpec::all_tables; the composition root supplies it along with the manage opt-out.

Trait Implementations

impl CaptureProvisioning for WalChangeCapture

fn inspect_coverage<'life0, 'life1, 'async_trait>( &'life0 self, required: &'life1 BTreeSet<QualifiedTable>, ) -> Pin<Box<dyn Future<Output = Result<CoverageReport>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Read-only: report coverage of required against what the source streams, and whether the gap (if any) is manageable. Never mutates anything.

fn ensure_coverage<'life0, 'life1, 'async_trait>( &'life0 self, required: &'life1 BTreeSet<QualifiedTable>, manage: bool, ) -> Pin<Box<dyn Future<Output = Result<CoverageReport>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Provision any missing tables when manage is set and the gap is manageable; otherwise a no-op. Returns the report as observed before acting (so a caller can log what was — or would have been — done). A no-op for an already-satisfied set.

impl ChangeCapture for WalChangeCapture

fn lag<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Option<u64>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Bytes between the slot’s confirmed_flush_lsn and the server’s current WAL LSN — how far behind the destination is. Returns None until the slot exists (it is created on the first live connect).

fn live<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<BoxStream<'static, Result<Change>>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait,

Connect, ensure setup, resume from the last confirmed point, and stream live changes.

fn snapshot<'life0, 'life1, 'async_trait>( &'life0 self, tables: &'life1 [SnapshotTable], ) -> Pin<Box<dyn Future<Output = Result<BoxStream<'static, Result<Change>>>> + Send + 'async_trait>>

where Self: 'async_trait, 'life0: 'async_trait, 'life1: 'async_trait,

Snapshot the current rows of tables as a finite stream of Upsert changes — the rows to seed an index with. The stream ends when the snapshot is complete; there is no in-band boundary marker.

impl Clone for WalChangeCapture

fn clone(&self) -> WalChangeCapture

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for WalChangeCapture

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.