CHANGELOG.md in event_sourcery-0.22.0 vs CHANGELOG.md in event_sourcery-0.23.0

@@ -3,10 +3,68 @@
 All notable changes to this project will be documented in this file.
 
 The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
+## [Unreleased]
+
+## [0.23.0] - 2019-07-11
+### Added
+- Add Ruby 2.6 to the CI test matrix.
+- `ESPRunner` supports an `after_subprocess_termination` hook. This optional
+  initializer argument will will be executed when each child process
+  terminates. This allows for monitoring and alerts to be configured.
+  For example, Rollbar:
+
+  ```ruby
+  EventSourcery::EventProcessing::ESPRunner.new(
+    event_processors: processors,
+    event_source: source,
+    after_subprocess_termination: proc do |processor:, runner:, exit_status:|
+      if exit_status != 0
+        Rollbar.error("Processor #{processor.processor_name} "\
+                      "terminated with exit status #{exit_status}")
+      end
+    end
+  ).start!
+  ```
+
+- `ESPRunner` exposes three new public methods `start_processor`, `shutdown`,
+  and `shutdown_requested?`. These provide options for handling subprocess
+  failure/termination. For example, shutting down the `ESPRunner`:
+
+  ```ruby
+  EventSourcery::EventProcessing::ESPRunner.new(
+    event_processors: processors,
+    event_source: source,
+    after_subprocess_termination: proc do |processor:, runner:, exit_status:|
+      runner.shutdown
+    end
+  ).start!
+  ```
+
+  Or restarting the event processor:
+
+  ```ruby
+  EventSourcery::EventProcessing::ESPRunner.new(
+    event_processors: processors,
+    event_source: source,
+    after_subprocess_termination: proc do |processor:, runner:, exit_status:|
+      runner.start_processor(processor) unless runner.shutdown_requested?
+    end
+  ).start!
+  ```
+
+- `ESPRunner` checks for dead child processes every second. This means we
+  shouldn't see `[ruby] <defunct>` in the process list (ps) when a processor
+  fails.
+- `ESPRunner` logs when child processes die.
+- `ESPRunner` logs when sending signals to child processes.
+
+### Removed
+- Remove Ruby 2.2 from the CI test matrix.
+
 ## [0.22.0] - 2018-10-04
 ### Added
 - Log critical exceptions to the application provided block via the new
   configuration option ([#209](https://github.com/envato/event_sourcery/pull/209)):
 
@@ -27,11 +85,11 @@
 - Fixed a bug where ESPRunner would raise an error under certain circumstances
   ([#203](https://github.com/envato/event_sourcery/pull/203)).
 
 ## [0.20.0] - 2018-06-21
 ### Changed
-- Changed signature of `ESPProcess#initialize` to include a default value for `after_fork`. This prevents the 
+- Changed signature of `ESPProcess#initialize` to include a default value for `after_fork`. This prevents the
 `after_fork` change from 0.19.0 from being a breaking change to external creators of ESPProcess.
 - Added more logging when a fatal exception occurs in ESPProcess
 
 ## [0.19.0] - 2018-06-06
 ### Added
@@ -161,10 +219,11 @@
 
 ### Removed
 - EventSourcery no longer depends on Virtus.
 - `Command` and `CommandHandler` have been removed.
 
-[Unreleased]: https://github.com/envato/event_sourcery/compare/v0.22.0...HEAD
+[Unreleased]: https://github.com/envato/event_sourcery/compare/v0.23.0...HEAD
+[0.23.0]: https://github.com/envato/event_sourcery/compare/v0.22.0...v0.23.0
 [0.22.0]: https://github.com/envato/event_sourcery/compare/v0.21.0...v0.22.0
 [0.21.0]: https://github.com/envato/event_sourcery/compare/v0.20.0...v0.21.0
 [0.20.0]: https://github.com/envato/event_sourcery/compare/v0.19.0...v0.20.0
 [0.19.0]: https://github.com/envato/event_sourcery/compare/v0.18.0...v0.19.0
 [0.18.0]: https://github.com/envato/event_sourcery/compare/v0.17.0...v0.18.0