Elastalert2

Breaking changes
- None

New features
- Add support for RocketChat - [182](https://github.com/jertel/elastalert2/pull/182) - nsano-rururu
- Expose rule scheduler properties as configurable settings - [192](https://github.com/jertel/elastalert2/pull/192) - jertel
- Exclude empty observables from TheHive requests - [193](https://github.com/jertel/elastalert2/pull/193) - LaZyDK
- Ensure TheHive tags are converted to strings before submitting TheHive request - [206](https://github.com/jertel/elastalert2/pull/206) - LaZyDK
- Add support for Elasticsearch API key authentication - [208](https://github.com/jertel/elastalert2/pull/208) - vbisserie
- Add support for Elasticsearch 7.13 for building Kibana Discover URLs - [212](https://github.com/jertel/elastalert2/pull/212) - nsano-rururu
- Follow symbolic links when traversing rules folder for rule files - [214](https://github.com/jertel/elastalert2/pull/214) - vbisserie
- Support optional suppression of SSL log warnings when http-posting alerts - [222](https://github.com/jertel/elastalert2/pull/222) - nsano-rururu
- Add support for inclusion of Kibana Discover URLs in MatterMost messages - [239](https://github.com/jertel/elastalert2/pull/239) - nsano-rururu
- Add support for inclusion of alert Title in MatterMost messages - [246](https://github.com/jertel/elastalert2/pull/246) - nsano-rururu

Other changes
- Speed up unit tests by adding default parallelism - [164](https://github.com/jertel/elastalert2/pull/164) - ferozsalam
- Remove unused writeback_alias and fix --patience argument - [167](https://github.com/jertel/elastalert2/pull/167) - mrfroggg
- Fix Bearer token auth in initialisation script - [169](https://github.com/jertel/elastalert2/pull/169) - ferozsalam
- Finish refactoring alerters and tests into individual files - [175, et al](https://github.com/jertel/elastalert2/pull/175) - ferozsalam
- Improve HTTP POST alert documentation - [178](https://github.com/jertel/elastalert2/pull/178) - nsano-rururu
- Upgrade Sphinx from 3.5.4 to 4.0.2 - [179](https://github.com/jertel/elastalert2/pull/179) - nsano-rururu
- Fix Sphinx dependency version - [181](https://github.com/jertel/elastalert2/pull/181) - ferozsalam
- Switch to absolute imports - [198](https://github.com/jertel/elastalert2/pull/198) - ferozsalam
- Encode JSON output before writing test data - [215](https://github.com/jertel/elastalert2/pull/215) - vbisserie
- Update pytest from 6.0.0 to 6.2.4 - [223](https://github.com/jertel/elastalert2/pull/223/files) - nsano-rururu
- Ensure ChatWork alerter fails to initialize if missing required args - [224](https://github.com/jertel/elastalert2/pull/224) - nsano-rururu
- Ensure DataDog alerter fails to initialize if missing required args - [225](https://github.com/jertel/elastalert2/pull/225) - nsano-rururu
- Ensure DingTalk alerter fails to initialize if missing required args - [226](https://github.com/jertel/elastalert2/pull/226) - nsano-rururu
- Ensure Zabbix alerter fails to initialize if missing required args - [227](https://github.com/jertel/elastalert2/pull/227) - nsano-rururu
- MS Teams alerter no longer requires ms_teams_alert_summary arg - [228](https://github.com/jertel/elastalert2/pull/228) - nsano-rururu
- Improve Gitter alerter by explicitly specifying arg names - [230](https://github.com/jertel/elastalert2/pull/230) - nsano-rururu
- Add more alerter test code coverage - [231](https://github.com/jertel/elastalert2/pull/231) - nsano-rururu
- Upgrade pytest-cov from 2.12.0 to 2.12.1 - [232](https://github.com/jertel/elastalert2/pull/232) - nsano-rururu
- Migrate away from external test mock dependency - [233](https://github.com/jertel/elastalert2/pull/233) - nsano-rururu
- Improve ElastAlert 2 documentation relating to running scenarios - [234](https://github.com/jertel/elastalert2/pull/234) - ferozsalam
- Improve test coverage and correct dict lookup syntax for alerter init functions - [235](https://github.com/jertel/elastalert2/pull/235) - nsano-rururu
- Fix schema bug with MatterMost alerts - [239](https://github.com/jertel/elastalert2/pull/239) - nsano-rururu
- Fix prometheus wrapper writeback function signature - [253](https://github.com/jertel/elastalert2/pull/253) - greut

Breaking changes
- TheHive alerter refactoring - [142](https://github.com/jertel/elastalert2/pull/142) - ferozsalam
- See the updated documentation for changes required to alert formatting
- Dockerfile refactor for performance and size improvements - [102](https://github.com/jertel/elastalert2/pull/102) - jgregmac
- Dockerfile base image changed from `python/alpine` to `python/slim-buster` to take advantage of pre-build python wheels, accelerate build times, and reduce image size. If you have customized an image, based on jertel/elastalert2, you may need to make adjustments.
- Default base path changed to `/opt/elastalert` in the Dockerfile and in Helm charts. Update your volume binds accordingly.
- Dockerfile now runs as a non-root user "elastalert". Ensure your volumes are accessible by this non-root user.
- System packages removed from the Dockerfile: All dev packages, cargo, libmagic. Image size reduced to 250Mb.
- `tmp` files and dev packages removed from the final container image.

New features
- Support for multiple rules directories and fix `..data` Kubernetes/Openshift recursive directories in FileRulesLoader [157](https://github.com/jertel/elastalert2/pull/157) - mrfroggg
- Support environment variable substition in yaml files - [149](https://github.com/jertel/elastalert2/pull/149) - archfz
- Update schema.yaml and enhance documentation for Email alerter - [144](https://github.com/jertel/elastalert2/pull/144) - nsano-rururu
- Default Email alerter to use port 25, and require http_post_url for HTTP Post alerter - [143](https://github.com/jertel/elastalert2/pull/143) - nsano-rururu
- Support extra message features for Slack and Mattermost - [140](https://github.com/jertel/elastalert2/pull/140) - nsano-rururu
- Support a footer in alert text - [133](https://github.com/jertel/elastalert2/pull/133) - nsano-rururu
- Added support for alerting via Amazon Simple Email System (SES) - [105](https://github.com/jertel/elastalert2/pull/105) - nsano-rururu

Other changes
- Begin alerter refactoring to split large source code files into smaller files - [161](https://github.com/jertel/elastalert2/pull/161) - ferozsalam
- Update contribution guidelines with additional instructions for local testing - [147](https://github.com/jertel/elastalert2/pull/147), [#148](https://github.com/jertel/elastalert2/pull/148) - ferozsalam
- Add more unit test coverage - [108](https://github.com/jertel/elastalert2/pull/108) - nsano-rururu
- Update documentation: describe limit_execution, correct alerters list - [107](https://github.com/jertel/elastalert2/pull/107) - fberrez
- Fix issue with testing alerts that contain Jinja templates - [101](https://github.com/jertel/elastalert2/pull/101) - jertel
- Updated all references of Elastalert to use the mixed case ElastAlert, as that is the most prevalent formatting found in the documentation.

Breaking changes
- None

New features
- Update python-dateutil requirement from <2.7.0,>=2.6.0 to >=2.6.0,<2.9.0 - [96](https://github.com/jertel/elastalert2/pull/96) - nsano-rururu
- Update pylint requirement from <2.8 to <2.9 - [95](https://github.com/jertel/elastalert2/pull/95) - nsano-rururu
- Pin ES library to 7.0.0 due to upcoming newer library conflicts - [90](https://github.com/jertel/elastalert2/pull/90) - robrankin
- Re-introduce CHANGELOG.md to project - [88](https://github.com/jertel/elastalert2/pull/88) - ferozsalam
- Add option for suppressing TLS warnings - [87](https://github.com/jertel/elastalert2/pull/87) - alvarolmedo
- Add support for Twilio Copilot - [86](https://github.com/jertel/elastalert2/pull/86) - cdmastercom
- Support bearer token authentication with ES - [85](https://github.com/jertel/elastalert2/pull/85) - StribPav
- Add support for statsd metrics - [83](https://github.com/jertel/elastalert2/pull/83) - eladamitpxi
- Add support for multiple imports of rules via recursive import - [83](https://github.com/jertel/elastalert2/pull/83) - eladamitpxi
- Specify search size of 0 to improve efficiency of searches - [82](https://github.com/jertel/elastalert2/pull/82) - clyfish
- Add alert handler to create Datadog events - [81](https://github.com/jertel/elastalert2/pull/81) - 3vanlock

Other changes

- Added missing Helm chart config.yaml template file.
- Update .gitignore with more precise rule for /config.yaml file.
- Now publishing container images to both DockerHub and to GitHub Packages for redundancy.
- Container images are now built and published via GitHub actions instead of relying on DockerHub's automated builds.
- Update PIP library description and Helm chart description to be consistent.
- Continue updates to change references from _ElastAlert_ to _ElastAlert 2_