Creating a Store

Import the crate, create an EventSourcingDB client, and create a store by providing the client and the source to use for all events you write:

use architecturekit::{Store, eventsourcingdb::Client};

// ...

let base_url = "http://localhost:3000".parse()?;
let api_token = "secret";

let client = Client::new(base_url, api_token);
let store = Store::builder(client, "https://library.eventsourcingdb.io").build();

Store::builder returns a StoreBuilder, whose build method returns a Store, which reads and writes the events of all commands. ArchitectureKit brings the client SDK along as architecturekit::eventsourcingdb, so that its version always fits the one of the kit: a new major version of the client SDK comes with a new major version of the kit. For details on the client, see the client SDK for Rust.

Choosing the Source#

The second argument of Store::builder is the source for all events you write. Every event in EventSourcingDB has one, and it identifies the system that produced the event, such as https://library.eventsourcingdb.io. It must be a URI reference, such as a URL or a tag URI, and it does not affect how events are processed (see Sources).

Configuring the Store#

The builder has methods that configure the store before build creates it, so they can not change a store that is in use. There are these methods:

• conflict_retries has execute decide again on a conflict, up to the given number of times (see Guarding Against Concurrent Changes).
• state_cache keeps the states of the most recently used subjects in memory, up to the given number, where 0 keeps none (see Caching States).
• reconnect_delays sets how long running projections wait before they read again after reading failed or the stream ended (see Running Projections).
• reconnect_observer calls a function every time a running projection is about to wait before reading again, for example to log it (see Running Projections).
• signature_verification checks the signature of every event the store reads, besides its hash (see Verifying Events).
• without_hash_verification turns off checking the hash of every event the store reads, which the store does unless told otherwise (see Verifying Events).

Note that without_hash_verification can not be combined with signature_verification, since checking a signature includes checking the hash, so build panics if it gets both.