Struct Connection 

pub struct Connection { /* private fields */ }

A connection to an EvidentSource database with live metadata updates.

The connection maintains a background subscription to receive database updates whenever transactions are committed. This enables efficient access to the latest database state without polling.

Example

let es = EvidentSource::connect_to_server("http://localhost:50051").await?;
let conn = es.connect(&DatabaseName::new("my-db")?).await?;

// Get latest database state
let db = conn.latest_database().await?;
println!("Revision: {}", db.revision());

Implementations

impl Connection

pub async fn new( client: EvidentSourceClient, database_name: DatabaseName, ) -> Result<Self, DatabaseError>

Create a new connection to a database.

This fetches the initial database state and starts a background subscription to receive updates.

pub async fn close(self) -> Result<(), DatabaseError>

Explicitly close the connection and wait for cleanup.

impl Connection

pub fn list_state_changes( &self, ) -> impl Stream<Item = StateChangeDefinitionSummary>

List all state change definitions registered with this database.

Example

use futures::StreamExt;

let mut state_changes = conn.list_state_changes();
while let Some(sc) = state_changes.next().await {
    println!("State change: {} v{}", sc.name, sc.version);
}

pub async fn fetch_transaction_by_id( &self, transaction_id: &str, ) -> Result<Transaction, DatabaseError>

Fetch a transaction by its ID.

Example

let txn = conn.fetch_transaction_by_id("my-txn-id").await?;
println!("Transaction revision: {}", txn.summary.revision);

pub fn client(&self) -> &EvidentSourceClient

Get a reference to the underlying gRPC client.

This provides access to low-level operations not exposed through the high-level API.

pub fn transaction(&self) -> TransactionBuilder

Create a transaction builder for constructing transactions.

Example

let db = conn
    .transaction()
    .event(my_event)
    .require_not_exists(EventSelector::stream_equals("my-stream"))
    .commit()
    .await?;

pub fn state_change( &self, name: &str, version: StateChangeVersion, ) -> StateChangeBuilder

Create a state change builder for executing state changes.

Example

let db = conn
    .state_change("create-account", 1)
    .json(&CreateAccountRequest { name: "Alice" })?
    .execute()
    .await?;

Trait Implementations

impl Clone for Connection

fn clone(&self) -> Connection

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl DatabaseConnection for Connection

fn transact( &self, events: NonEmpty<ProspectiveEvent>, conditions: Vec<AppendCondition>, ) -> impl Future<Output = Result<Self::AtRevision, DatabaseError>>

Transact events with append conditions.

fn execute_state_change( &self, name: &StateChangeName, version: StateChangeVersion, request: CommandRequest, ) -> impl Future<Output = Result<Self::AtRevision, StateChangeError>>

Execute a state change.

fn log(&self) -> impl Stream<Item = TransactionSummary>

Get the transaction log (summary only).

fn log_detail(&self) -> impl Stream<Item = Transaction>

Get the transaction log with full event details.

fn transact_with_id( &self, transaction_id: &str, events: NonEmpty<ProspectiveEvent>, conditions: Vec<AppendCondition>, ) -> impl Future<Output = Result<Self::AtRevision, DatabaseError>>

Transact events with a custom transaction ID.

fn log_from( &self, from_revision: Revision, ) -> impl Stream<Item = TransactionSummary>

Get the transaction log starting from a specific revision.

fn log_detail_from( &self, from_revision: Revision, ) -> impl Stream<Item = Transaction>

Get the transaction log with full event details, starting from a specific revision.

impl DatabaseConnectionAsync for Connection

fn transact_async( &self, events: NonEmpty<ProspectiveEvent>, conditions: Vec<AppendCondition>, ) -> impl Future<Output = Result<CorrelationId, DatabaseError>>

Transact asynchronously.

fn transact_async_with_id( &self, transaction_id: &str, events: NonEmpty<ProspectiveEvent>, conditions: Vec<AppendCondition>, ) -> impl Future<Output = Result<CorrelationId, DatabaseError>>

Transact asynchronously with a specific transaction ID.

fn execute_state_change_async( &self, name: &StateChangeName, version: StateChangeVersion, request: CommandRequest, ) -> impl Future<Output = Result<CorrelationId, StateChangeError>>

Execute a state change asynchronously.

impl DatabaseIdentity for Connection

fn name(&self) -> &DatabaseName

Get the database name.

fn created_at(&self) -> DateTime<Utc>

Get the timestamp when this database was created.

impl DatabaseProvider for Connection

type AtRevision = DatabaseAtRevisionImpl

The type of database view at a specific revision.

fn local_database(&self) -> Self::AtRevision

Get the latest local database

fn latest_database( &self, ) -> impl Future<Output = Result<Self::AtRevision, DatabaseError>>

Get the latest revision on the server committed to storage.

fn database_at_revision( &self, revision: u64, ) -> impl Future<Output = Result<Self::AtRevision, DatabaseError>>

Get the database at a specific revision, awaiting if necessary.

fn database_at_timestamp( &self, revision_timestamp: DateTime<Utc>, ) -> impl Future<Output = Result<Self::AtRevision, DatabaseError>>

Get the database at the revision effective at a specific timestamp.

impl Debug for Connection

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

Formats the value using the given formatter.