Expose option for setting ID function (#202)

* Add ID format to `PgStore`

* Allow `PgStoreBuilder` to set ID format

* Support UUID version 7 directly

Cargo.toml

@@ -29,7 +29,7 @@ tokio = { version = "1.6", optional = true }
 serde = { version = "1.0", features = ["derive"] }
 serde_json = "1.0"
 # Uuid generation
-uuid = { version = "1.1", features = ["serde", "v4"] }
+uuid = { version = "1.6", features = ["serde", "v4", "v7"] }
 # Time esrs-core
 chrono = { version = "0.4", features = ["serde"] }
 # Build async trait

src/store/postgres/builder.rs

@@ -14,6 +14,15 @@ use crate::Aggregate;
 use super::persistable::Persistable;
 use super::{PgStore, Schema};
 
+/// The `UuidFormat` enum defines the UUID format preference:
+///
+/// - `V4`: Uses the random UUID version 4 as defined by RFC 9562 section 5.4.
+/// - `V7`: Uses the time-ordered UUID version 7 as defined by RFC 9562 section 5.7.
+pub enum UuidFormat {
+    V4,
+    V7,
+}
+
 /// Struct used to build a brand new [`PgStore`].
 pub struct PgStoreBuilder<A, Schema = <A as Aggregate>::Event>
 where
@@ -24,6 +33,7 @@ where
     event_handlers: Vec<Box<dyn EventHandler<A> + Send>>,
     transactional_event_handlers: Vec<Box<dyn TransactionalEventHandler<A, PgStoreError, PgConnection> + Send>>,
     event_buses: Vec<Box<dyn EventBus<A> + Send>>,
+    event_id_format: UuidFormat,
     run_migrations: bool,
     _schema: PhantomData<Schema>,
 }
@@ -40,6 +50,7 @@ where
             event_handlers: vec![],
             transactional_event_handlers: vec![],
             event_buses: vec![],
+            event_id_format: UuidFormat::V4,
             run_migrations: true,
             _schema: PhantomData,
         }
@@ -112,10 +123,17 @@ where
             event_handlers: self.event_handlers,
             transactional_event_handlers: self.transactional_event_handlers,
             event_buses: self.event_buses,
+            event_id_format: self.event_id_format,
             _schema: PhantomData,
         }
     }
 
+    /// Set the UUID format of event IDs.
+    pub fn with_event_id_format(mut self, event_id_format: UuidFormat) -> Self {
+        self.event_id_format = event_id_format;
+        self
+    }
+
     /// This function runs all the needed [`Migrations`], atomically setting up the database if
     /// `run_migrations` isn't explicitly set to false. [`Migrations`] should be run only at application
     /// startup due to avoid performance issues.
@@ -137,6 +155,7 @@ where
                 event_handlers: RwLock::new(self.event_handlers),
                 transactional_event_handlers: self.transactional_event_handlers,
                 event_buses: self.event_buses,
+                event_id_format: self.event_id_format,
             }),
             _schema: self._schema,
         })

src/store/postgres/event_store.rs

@@ -19,6 +19,7 @@ use crate::sql::statements::{Statements, StatementsHandler};
 use crate::store::postgres::persistable::Persistable;
 use crate::store::postgres::PgStoreError;
 use crate::store::postgres::Schema;
+use crate::store::postgres::UuidFormat;
 use crate::store::{EventStore, EventStoreLockGuard, StoreEvent, UnlockOnDrop};
 use crate::types::SequenceNumber;
 use crate::{Aggregate, AggregateState};
@@ -58,6 +59,7 @@ where
     pub(super) transactional_event_handlers:
         Vec<Box<dyn TransactionalEventHandler<A, PgStoreError, PgConnection> + Send>>,
     pub(super) event_buses: Vec<Box<dyn EventBus<A> + Send>>,
+    pub(super) event_id_format: UuidFormat,
 }
 
 impl<A, S> PgStore<A, S>
@@ -95,7 +97,10 @@ where
         sequence_number: SequenceNumber,
         executor: impl Executor<'_, Database = Postgres>,
     ) -> Result<StoreEvent<A::Event>, PgStoreError> {
-        let id: Uuid = Uuid::new_v4();
+        let id: Uuid = match self.inner.event_id_format {
+            UuidFormat::V4 => Uuid::new_v4(),
+            UuidFormat::V7 => Uuid::now_v7(),
+        };
 
         #[cfg(feature = "upcasting")]
         let version: Option<i32> = S::current_version();