r2d2

Added

• Added a HandleEvent trait used to listen for various events from the pool for monitoring purposes.

Changed

• Switched from standard library synchronization primitives to parking_lot.

Fixed

• The set of idle connections is now treated as a stack rather than a queue. The old behavior interacted poorly with configurations that allowed the pool size to shrink when mostly idle.

Changed

• Upgraded from log 0.3 to 0.4.

Fixed

• Fixed the example in the README.

Changed

• Pool configuration has changed. Rather than constructing a Config and passing it to the Pool constructor, you now configure a Builder which then directly constructs the pool:

  // In 0.7.x
  let config = Config::builder()
      .min_idle(3)
      .build();
  let pool = Pool::new(config, manager)?;
  
  // In 0.8.x
  let pool = Pool::builder()
      .min_idle(3)
      .build(manager)?;
  

• The Pool::new method can be used to construct a Pool with default settings:

  // In 0.7.x
  let config = Config::default();
  let pool = Pool::new(config, manager)?;
  
  // In 0.8.x
  let pool = Pool::new(manager)?;
  

• The initialization_fail_fast configuration option has been replaced with separate Builder::build and Builder::build_unchecked methods. The second returns a Pool directly without wrapping it in a Result, and does not check that connections are being successfully opened:

  // In 0.7.x
  let config = Config::builder()
      .initialization_fail_fast(false)
      .build();
  let pool = Pool::new(config, manager).unwrap();
  
  // In 0.8.x
  let pool = Pool::builder().build_unchecked(manager);
  

• The InitializationError and GetTimeout error types have been merged into a unified Error type.

• The Pool::config method has been replaced with accessor methods on Pool to directly access configuration, such as Pool::min_idle.

• The scheduled_thread_pool crate has been upgraded from 0.1 to 0.2.

Removed

• The deprecated Builder::num_threads method has been removed. Construct a ScheduledThreadPool and set it via Builder::thread_pool instead.