Struct SpannerSource 

pub struct SpannerSource { /* private fields */ }

Google Cloud Spanner query source.

Implementations

impl SpannerSource

pub async fn new(config: SpannerSourceConfig) -> Result<Self, FaucetError>

Validate the config and build the Spanner client (session pool).

Trait Implementations

impl Source for SpannerSource

fn discover<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Vec<DatasetDescriptor>, FaucetError>> + Send + 'async_trait>>

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

Enumerate every base table in the database’s default schema with column types from INFORMATION_SCHEMA.COLUMNS (catalog metadata only — no data scan). System schemas (INFORMATION_SCHEMA, SPANNER_SYS) carry a non-empty TABLE_SCHEMA, so filtering on the default (empty) schema excludes them. Spanner exposes no cheap row estimate, so descriptors carry none.

fn is_shardable(&self) -> bool

Shardable when a ShardConfig is set.

fn enumerate_shards<'life0, 'async_trait>( &'life0 self, target: usize, ) -> Pin<Box<dyn Future<Output = Result<Vec<ShardSpec>, FaucetError>> + Send + 'async_trait>>

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

Enumerate contiguous primary-key range shards by computing the key column’s MIN/MAX over the (unsharded) base query and splitting that range into ~target slices. Returns a single whole-dataset shard when no shard config is set or the result set is empty.

The base query is resolved through the same query builder as a normal fetch first, so a @bookmark parameter (incremental replication) is bound rather than left dangling — bounds are then computed over the not-yet-synced slice, which is exactly the data the shards will read.

fn apply_shard<'life0, 'life1, 'async_trait>( &'life0 self, shard: &'life1 ShardSpec, ) -> Pin<Box<dyn Future<Output = Result<(), FaucetError>> + Send + 'async_trait>>

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

Narrow this source to a single PK-range shard. The whole-dataset shard clears any applied range (streams the full query).

fn fetch_with_context<'life0, 'life1, 'async_trait>( &'life0 self, context: &'life1 HashMap<String, Value>, ) -> Pin<Box<dyn Future<Output = Result<Vec<Value>, FaucetError>> + Send + 'async_trait>>

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

Primary fetch method. Receives context from a parent source’s records.

fn fetch_with_context_incremental<'life0, 'life1, 'async_trait>( &'life0 self, context: &'life1 HashMap<String, Value>, ) -> Pin<Box<dyn Future<Output = Result<(Vec<Value>, Option<Value>), FaucetError>> + Send + 'async_trait>>

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

Incremental fetch with parent context support.

fn stream_pages<'a>( &'a self, context: &'a HashMap<String, Value>, _batch_size: usize, ) -> Pin<Box<dyn Stream<Item = Result<StreamPage, FaucetError>> + Send + 'a>>

Stream records page-by-page so the pipeline can write to the sink as pages arrive instead of buffering the full result set.

fn config_schema(&self) -> Value

Return a JSON Schema describing the configuration this source accepts.

fn connector_name(&self) -> &'static str

Stable identifier used as the connector label on metrics and the connector attribute on spans. Defaults to the final segment of std::any::type_name::<Self>(), e.g. "RestSource". Built-in connectors override with a short, friendly snake_case name (e.g. "rest"). Must return a non-empty string; observability decorators fall back to "unknown" in release builds if it is empty (and debug_assert! in debug builds).

fn dataset_uri(&self) -> String

Logical dataset identity for lineage emission, following OpenLineage naming conventions (https://openlineage.io/docs/spec/naming).

fn state_key(&self) -> Option<String>

Stable key under which this source’s incremental-replication bookmark should be persisted in a StateStore.

fn apply_start_bookmark<'life0, 'async_trait>( &'life0 self, bookmark: Value, ) -> Pin<Box<dyn Future<Output = Result<(), FaucetError>> + Send + 'async_trait>>

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

Apply a bookmark loaded from a StateStore as this run’s starting point.

fn supports_discover(&self) -> bool

Whether this source can enumerate the datasets behind its connection via discover. Default: false. Sources backed by an introspectable catalog (database information_schema, MongoDB collections, Elasticsearch indices, object-store prefixes) override this to true.

fn fetch_all<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<Vec<Value>, FaucetError>> + Send + 'async_trait>>

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

Convenience: fetch with no parent context.

fn fetch_all_incremental<'life0, 'async_trait>( &'life0 self, ) -> Pin<Box<dyn Future<Output = Result<(Vec<Value>, Option<Value>), FaucetError>> + Send + 'async_trait>>

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

Convenience: incremental fetch with no parent context.

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

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

Capture the source’s current replication position without consuming any changes, ensuring any server-side resource (e.g. a logical replication slot) needed to later resume from that position exists.

fn supports_exactly_once(&self) -> bool

Whether this source deterministically replays the same page sequence from a given bookmark — the requirement for the atomic-watermark effectively-once path (a non-deterministic replay could cause the pipeline to skip a page whose contents differ from the one already committed). Default: false.

fn replay_guarantee(&self) -> ReplayGuarantee

The typed replay capability this source advertises — see ReplayGuarantee.

fn check<'life0, 'life1, 'async_trait>( &'life0 self, ctx: &'life1 CheckContext, ) -> Pin<Box<dyn Future<Output = Result<CheckReport, FaucetError>> + Send + 'async_trait>>

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

Run a fast, non-mutating preflight probe (used by faucet doctor).