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DataConn

sabi

Trait DataConn 

Source 
pub trait DataConn {
    // Required methods
    fn commit(&mut self, ag: &mut AsyncGroup) -> Result<()>;
    fn is_committed(&self) -> bool;
    fn rollback(&mut self, ag: &mut AsyncGroup) -> Result<()>;
    fn close(&mut self);

    // Provided methods
    fn pre_commit(&mut self, ag: &mut AsyncGroup) -> Result<()> { ... }
    fn post_commit(&mut self, ag: &mut AsyncGroup) -> Result<()> { ... }
    fn on_txn_failure(
        &mut self,
        ag: &mut AsyncGroup,
        reports: &[TxnFailureReport],
    ) { ... }
}
Expand description

The trait that abstracts a connection per session to an external data service, such as a database, file system, or messaging service.

Its primary purpose is to enable cohesive transaction operations across multiple external data services within a single transaction context. Implementations of this trait provide the concrete input/output operations for their respective data services.

Methods declared within this trait are designed to handle transactional logic. The AsyncGroup parameter in various methods allows for concurrent processing when commit or rollback operations are time-consuming.

Required Methods§

Source

fn commit(&mut self, ag: &mut AsyncGroup) -> Result<()>

Attempts to commit the changes made within this data connection’s transaction.

This method should encapsulate the logic required to finalize the transaction for the specific external data service.

§Parameters
  • ag: A mutable reference to an AsyncGroup for potentially offloading time-consuming commit operations to a separate thread.
§Returns
  • errs::Result<()>: Ok(()) if the commit is successful, or an errs::Err if the commit fails.
Source

fn is_committed(&self) -> bool

Returns whether the transaction on this connection has been successfully committed.

Source

fn rollback(&mut self, ag: &mut AsyncGroup) -> Result<()>

Rolls back any changes made within this data connection’s transaction.

This method undoes all operations performed since the beginning of the transaction, restoring the data service to its state before the transaction began.

§Parameters
  • ag: A mutable reference to an AsyncGroup. This can be used to run the rollback asynchronously in a separate thread.
§Returns
  • errs::Result<()>: Ok(()) if the rollback is successful, or an errs::Err if it fails.
Source

fn close(&mut self)

Closes the connection to the external data service.

This method should release any resources held by the data connection, ensuring a graceful shutdown of the connection.

Provided Methods§

Source

fn pre_commit(&mut self, ag: &mut AsyncGroup) -> Result<()>

This method is executed before the transaction commit process for all DataConn instances involved in the transaction.

This method provides a timing to execute unusual commit processes or update operations not supported by transactions beforehand. This allows other update operations to be rolled back if the operations in this method fail.

§Parameters
  • ag: A mutable reference to an AsyncGroup. This can be used to run the pre-commit asynchronously in a separate thread.
§Returns
  • errs::Result<()>: Ok(()) if pre-commit is successful, or an errs::Err if it fails.
Source

fn post_commit(&mut self, ag: &mut AsyncGroup) -> Result<()>

This method is executed after the transaction commit process has successfully completed for all DataConn instances involved in the transaction.

It provides a moment to perform follow-up actions that depend on a successful commit. For example, after a database commit, a messaging service’s DataConn might use this method to send a “transaction completed” message.

§Parameters
  • ag: A mutable reference to an AsyncGroup for potentially offloading concurrent post-commit operations.
§Returns
  • errs::Result<()>: Ok(()) if post-commit tasks succeed, or an errs::Err if they fail.
Source

fn on_txn_failure(&mut self, ag: &mut AsyncGroup, reports: &[TxnFailureReport])

A lifecycle callback invoked when a transaction fails and a rollback is executed.

This allows the data connection to handle post-failure tasks or custom logic based on the provided transaction failure reports.

§Parameters
  • ag: A mutable reference to an AsyncGroup for asynchronous task execution.
  • reports: A slice of TxnFailureReport containing failure details for all connections.

Dyn Compatibility§

This trait is dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety".

Implementors§