Transactions Isolation level and Access mode

src/database/connection.rs

@@ -47,13 +47,63 @@ pub trait StreamTrait: Send + Sync {
     ) -> Pin<Box<dyn Future<Output = Result<Self::Stream<'a>, DbErr>> + 'a + Send>>;
 }
 
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+/// Isolation level
+pub enum IsolationLevel {
+    /// Consistent reads within the same transaction read the snapshot established by the first read.
+    RepeatableRead,
+    /// Each consistent read, even within the same transaction, sets and reads its own fresh snapshot.
+    ReadCommitted,
+    /// SELECT statements are performed in a nonlocking fashion, but a possible earlier version of a row might be used.
+    ReadUncommitted,
+    /// All statements of the current transaction can only see rows committed before the first query or data-modification statement was executed in this transaction.
+    Serializable,
+}
+
+impl std::fmt::Display for IsolationLevel {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            IsolationLevel::RepeatableRead => write!(f, "REPEATABLE READ"),
+            IsolationLevel::ReadCommitted => write!(f, "READ COMMITTED"),
+            IsolationLevel::ReadUncommitted => write!(f, "READ UNCOMMITTED"),
+            IsolationLevel::Serializable => write!(f, "SERIALIZABLE"),
+        }
+    }
+}
+
+#[derive(Copy, Clone, Debug, PartialEq, Eq)]
+/// Access mode
+pub enum AccessMode {
+    /// Data can't be modified in this transaction
+    ReadOnly,
+    /// Data can be modified in this transaction (default)
+    ReadWrite,
+}
+
+impl std::fmt::Display for AccessMode {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        match self {
+            AccessMode::ReadOnly => write!(f, "READ ONLY"),
+            AccessMode::ReadWrite => write!(f, "READ WRITE"),
+        }
+    }
+}
+
 /// Spawn database transaction
 #[async_trait::async_trait]
 pub trait TransactionTrait {
     /// Execute SQL `BEGIN` transaction.
     /// Returns a Transaction that can be committed or rolled back
     async fn begin(&self) -> Result<DatabaseTransaction, DbErr>;
 
+    /// Execute SQL `BEGIN` transaction with isolation level and/or access mode.
+    /// Returns a Transaction that can be committed or rolled back
+    async fn begin_with_config(
+        &self,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
+    ) -> Result<DatabaseTransaction, DbErr>;
+
     /// Execute the function inside a transaction.
     /// If the function returns an error, the transaction will be rolled back. If it does not return an error, the transaction will be committed.
     async fn transaction<F, T, E>(&self, callback: F) -> Result<T, TransactionError<E>>
@@ -64,4 +114,20 @@ pub trait TransactionTrait {
             + Send,
         T: Send,
         E: std::error::Error + Send;
+
+    /// Execute the function inside a transaction with isolation level and/or access mode.
+    /// If the function returns an error, the transaction will be rolled back. If it does not return an error, the transaction will be committed.
+    async fn transaction_with_config<F, T, E>(
+        &self,
+        callback: F,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
+    ) -> Result<T, TransactionError<E>>
+    where
+        F: for<'c> FnOnce(
+                &'c DatabaseTransaction,
+            ) -> Pin<Box<dyn Future<Output = Result<T, E>> + Send + 'c>>
+            + Send,
+        T: Send,
+        E: std::error::Error + Send;
 }

src/database/db_connection.rs

@@ -1,6 +1,6 @@
 use crate::{
-    error::*, ConnectionTrait, DatabaseTransaction, ExecResult, QueryResult, Statement,
-    StatementBuilder, StreamTrait, TransactionError, TransactionTrait,
+    error::*, AccessMode, ConnectionTrait, DatabaseTransaction, ExecResult, IsolationLevel,
+    QueryResult, Statement, StatementBuilder, StreamTrait, TransactionError, TransactionTrait,
 };
 use sea_query::{MysqlQueryBuilder, PostgresQueryBuilder, QueryBuilder, SqliteQueryBuilder};
 use std::{future::Future, pin::Pin};
@@ -198,11 +198,38 @@ impl TransactionTrait for DatabaseConnection {
     async fn begin(&self) -> Result<DatabaseTransaction, DbErr> {
         match self {
             #[cfg(feature = "sqlx-mysql")]
-            DatabaseConnection::SqlxMySqlPoolConnection(conn) => conn.begin().await,
+            DatabaseConnection::SqlxMySqlPoolConnection(conn) => conn.begin(None, None).await,
             #[cfg(feature = "sqlx-postgres")]
-            DatabaseConnection::SqlxPostgresPoolConnection(conn) => conn.begin().await,
+            DatabaseConnection::SqlxPostgresPoolConnection(conn) => conn.begin(None, None).await,
             #[cfg(feature = "sqlx-sqlite")]
-            DatabaseConnection::SqlxSqlitePoolConnection(conn) => conn.begin().await,
+            DatabaseConnection::SqlxSqlitePoolConnection(conn) => conn.begin(None, None).await,
+            #[cfg(feature = "mock")]
+            DatabaseConnection::MockDatabaseConnection(conn) => {
+                DatabaseTransaction::new_mock(Arc::clone(conn), None).await
+            }
+            DatabaseConnection::Disconnected => panic!("Disconnected"),
+        }
+    }
+
+    #[instrument(level = "trace")]
+    async fn begin_with_config(
+        &self,
+        _isolation_level: Option<IsolationLevel>,
+        _access_mode: Option<AccessMode>,
+    ) -> Result<DatabaseTransaction, DbErr> {
+        match self {
+            #[cfg(feature = "sqlx-mysql")]
+            DatabaseConnection::SqlxMySqlPoolConnection(conn) => {
+                conn.begin(_isolation_level, _access_mode).await
+            }
+            #[cfg(feature = "sqlx-postgres")]
+            DatabaseConnection::SqlxPostgresPoolConnection(conn) => {
+                conn.begin(_isolation_level, _access_mode).await
+            }
+            #[cfg(feature = "sqlx-sqlite")]
+            DatabaseConnection::SqlxSqlitePoolConnection(conn) => {
+                conn.begin(_isolation_level, _access_mode).await
+            }
             #[cfg(feature = "mock")]
             DatabaseConnection::MockDatabaseConnection(conn) => {
                 DatabaseTransaction::new_mock(Arc::clone(conn), None).await
@@ -225,13 +252,61 @@ impl TransactionTrait for DatabaseConnection {
     {
         match self {
             #[cfg(feature = "sqlx-mysql")]
-            DatabaseConnection::SqlxMySqlPoolConnection(conn) => conn.transaction(_callback).await,
+            DatabaseConnection::SqlxMySqlPoolConnection(conn) => {
+                conn.transaction(_callback, None, None).await
+            }
+            #[cfg(feature = "sqlx-postgres")]
+            DatabaseConnection::SqlxPostgresPoolConnection(conn) => {
+                conn.transaction(_callback, None, None).await
+            }
+            #[cfg(feature = "sqlx-sqlite")]
+            DatabaseConnection::SqlxSqlitePoolConnection(conn) => {
+                conn.transaction(_callback, None, None).await
+            }
+            #[cfg(feature = "mock")]
+            DatabaseConnection::MockDatabaseConnection(conn) => {
+                let transaction = DatabaseTransaction::new_mock(Arc::clone(conn), None)
+                    .await
+                    .map_err(TransactionError::Connection)?;
+                transaction.run(_callback).await
+            }
+            DatabaseConnection::Disconnected => panic!("Disconnected"),
+        }
+    }
+
+    /// Execute the function inside a transaction.
+    /// If the function returns an error, the transaction will be rolled back. If it does not return an error, the transaction will be committed.
+    #[instrument(level = "trace", skip(_callback))]
+    async fn transaction_with_config<F, T, E>(
+        &self,
+        _callback: F,
+        _isolation_level: Option<IsolationLevel>,
+        _access_mode: Option<AccessMode>,
+    ) -> Result<T, TransactionError<E>>
+    where
+        F: for<'c> FnOnce(
+                &'c DatabaseTransaction,
+            ) -> Pin<Box<dyn Future<Output = Result<T, E>> + Send + 'c>>
+            + Send,
+        T: Send,
+        E: std::error::Error + Send,
+    {
+        match self {
+            #[cfg(feature = "sqlx-mysql")]
+            DatabaseConnection::SqlxMySqlPoolConnection(conn) => {
+                conn.transaction(_callback, _isolation_level, _access_mode)
+                    .await
+            }
             #[cfg(feature = "sqlx-postgres")]
             DatabaseConnection::SqlxPostgresPoolConnection(conn) => {
-                conn.transaction(_callback).await
+                conn.transaction(_callback, _isolation_level, _access_mode)
+                    .await
             }
             #[cfg(feature = "sqlx-sqlite")]
-            DatabaseConnection::SqlxSqlitePoolConnection(conn) => conn.transaction(_callback).await,
+            DatabaseConnection::SqlxSqlitePoolConnection(conn) => {
+                conn.transaction(_callback, _isolation_level, _access_mode)
+                    .await
+            }
             #[cfg(feature = "mock")]
             DatabaseConnection::MockDatabaseConnection(conn) => {
                 let transaction = DatabaseTransaction::new_mock(Arc::clone(conn), None)

src/database/transaction.rs

@@ -1,6 +1,6 @@
 use crate::{
-    debug_print, ConnectionTrait, DbBackend, DbErr, ExecResult, InnerConnection, QueryResult,
-    Statement, StreamTrait, TransactionStream, TransactionTrait,
+    debug_print, AccessMode, ConnectionTrait, DbBackend, DbErr, ExecResult, InnerConnection,
+    IsolationLevel, QueryResult, Statement, StreamTrait, TransactionStream, TransactionTrait,
 };
 #[cfg(feature = "sqlx-dep")]
 use crate::{sqlx_error_to_exec_err, sqlx_error_to_query_err};
@@ -31,11 +31,15 @@ impl DatabaseTransaction {
     pub(crate) async fn new_mysql(
         inner: PoolConnection<sqlx::MySql>,
         metric_callback: Option<crate::metric::Callback>,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
     ) -> Result<DatabaseTransaction, DbErr> {
         Self::begin(
             Arc::new(Mutex::new(InnerConnection::MySql(inner))),
             DbBackend::MySql,
             metric_callback,
+            isolation_level,
+            access_mode,
         )
         .await
     }
@@ -44,11 +48,15 @@ impl DatabaseTransaction {
     pub(crate) async fn new_postgres(
         inner: PoolConnection<sqlx::Postgres>,
         metric_callback: Option<crate::metric::Callback>,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
     ) -> Result<DatabaseTransaction, DbErr> {
         Self::begin(
             Arc::new(Mutex::new(InnerConnection::Postgres(inner))),
             DbBackend::Postgres,
             metric_callback,
+            isolation_level,
+            access_mode,
         )
         .await
     }
@@ -57,11 +65,15 @@ impl DatabaseTransaction {
     pub(crate) async fn new_sqlite(
         inner: PoolConnection<sqlx::Sqlite>,
         metric_callback: Option<crate::metric::Callback>,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
     ) -> Result<DatabaseTransaction, DbErr> {
         Self::begin(
             Arc::new(Mutex::new(InnerConnection::Sqlite(inner))),
             DbBackend::Sqlite,
             metric_callback,
+            isolation_level,
+            access_mode,
         )
         .await
     }
@@ -76,6 +88,8 @@ impl DatabaseTransaction {
             Arc::new(Mutex::new(InnerConnection::Mock(inner))),
             backend,
             metric_callback,
+            None,
+            None,
         )
         .await
     }
@@ -86,6 +100,8 @@ impl DatabaseTransaction {
         conn: Arc<Mutex<InnerConnection>>,
         backend: DbBackend,
         metric_callback: Option<crate::metric::Callback>,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
     ) -> Result<DatabaseTransaction, DbErr> {
         let res = DatabaseTransaction {
             conn,
@@ -96,21 +112,34 @@ impl DatabaseTransaction {
         match *res.conn.lock().await {
             #[cfg(feature = "sqlx-mysql")]
             InnerConnection::MySql(ref mut c) => {
+                // in MySQL SET TRANSACTION operations must be executed before transaction start
+                crate::driver::sqlx_mysql::set_transaction_config(c, isolation_level, access_mode)
+                    .await?;
                 <sqlx::MySql as sqlx::Database>::TransactionManager::begin(c)
                     .await
-                    .map_err(sqlx_error_to_query_err)?
+                    .map_err(sqlx_error_to_query_err)?;
             }
             #[cfg(feature = "sqlx-postgres")]
             InnerConnection::Postgres(ref mut c) => {
                 <sqlx::Postgres as sqlx::Database>::TransactionManager::begin(c)
                     .await
-                    .map_err(sqlx_error_to_query_err)?
+                    .map_err(sqlx_error_to_query_err)?;
+                // in PostgreSQL SET TRANSACTION operations must be executed inside transaction
+                crate::driver::sqlx_postgres::set_transaction_config(
+                    c,
+                    isolation_level,
+                    access_mode,
+                )
+                .await?;
             }
             #[cfg(feature = "sqlx-sqlite")]
             InnerConnection::Sqlite(ref mut c) => {
+                // in SQLite isolation level and access mode are global settings
+                crate::driver::sqlx_sqlite::set_transaction_config(c, isolation_level, access_mode)
+                    .await?;
                 <sqlx::Sqlite as sqlx::Database>::TransactionManager::begin(c)
                     .await
-                    .map_err(sqlx_error_to_query_err)?
+                    .map_err(sqlx_error_to_query_err)?;
             }
             #[cfg(feature = "mock")]
             InnerConnection::Mock(ref mut c) => {
@@ -415,6 +444,24 @@ impl TransactionTrait for DatabaseTransaction {
             Arc::clone(&self.conn),
             self.backend,
             self.metric_callback.clone(),
+            None,
+            None,
+        )
+        .await
+    }
+
+    #[instrument(level = "trace")]
+    async fn begin_with_config(
+        &self,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
+    ) -> Result<DatabaseTransaction, DbErr> {
+        DatabaseTransaction::begin(
+            Arc::clone(&self.conn),
+            self.backend,
+            self.metric_callback.clone(),
+            isolation_level,
+            access_mode,
         )
         .await
     }
@@ -434,6 +481,30 @@ impl TransactionTrait for DatabaseTransaction {
         let transaction = self.begin().await.map_err(TransactionError::Connection)?;
         transaction.run(_callback).await
     }
+
+    /// Execute the function inside a transaction with isolation level and/or access mode.
+    /// If the function returns an error, the transaction will be rolled back. If it does not return an error, the transaction will be committed.
+    #[instrument(level = "trace", skip(_callback))]
+    async fn transaction_with_config<F, T, E>(
+        &self,
+        _callback: F,
+        isolation_level: Option<IsolationLevel>,
+        access_mode: Option<AccessMode>,
+    ) -> Result<T, TransactionError<E>>
+    where
+        F: for<'c> FnOnce(
+                &'c DatabaseTransaction,
+            ) -> Pin<Box<dyn Future<Output = Result<T, E>> + Send + 'c>>
+            + Send,
+        T: Send,
+        E: std::error::Error + Send,
+    {
+        let transaction = self
+            .begin_with_config(isolation_level, access_mode)
+            .await
+            .map_err(TransactionError::Connection)?;
+        transaction.run(_callback).await
+    }
 }
 
 /// Defines errors for handling transaction failures