Servox

Fixed

- Include colorama package in release builds.

Fixed

- Include toml package in release builds.

Added

- Opsani Dev v2.0 integrated for rapid service optimization.
- Incorporated [uvloop](https://github.com/MagicStack/uvloop) for faster async
event loops.
- Initial release of Wavefront Connector.
- Support for marking adjustments as failed or rejected via exceptions.
- Multiple servos can now be run within a single assembly. If the config file is
a compound YAML document, multiple servos will be instantiated allowing the
concurrent optimization of multiple applications.
- Introduced emulator connector, which pretends to take measurements and make
adjustments with randomly sampled data but does not do any real work.
- New servo configurations can be generated and added to the assembly via
`servo generate --append`.
- New command `servo list` for viewing the active servos in the assembly.
- Introduced new top-level option `--name`/`-n` for targeting a specific servo
in the assembly when running in multi-servo mode.
- In multi-servo configurations, concurrency can be constrained via the new
top-level `--limit` option.
- Connector details for a particular servo instance can now be displayed via the
`servo show connectors` CLI command.
- Extensive new development and testing tooling.
- Introduced `servo.pubsub` module providing publisher/subscriber capabilities.
- The test suite now runs extensive integration and system tests under CI.
- All aspects of the Opsani Dev installation experience are now covered by
checks.
- Introduced the `attach` and `detach` lifeycle events for handling setup and
teardown concerns that need to execute when a Servo or Connector is added or
removed from am Assembly/Servo.
- Added automated checks.
- Introduced pub/sub module.

Enhanced

- The Kubernetes connector now recovers from and reports on numerous failure
modes such as unschedulable configurations.
- The Prometheus connector now exposes a Prometheus HTTP API client library.
- The Envoy sidecar can now be automatically injected via the CLI.
- The Opsani Dev connector now exposes a very simple configuration surface.

Changed

- The `__codename__` support has been generalized as `cryptonym` attribute for
all connectors.
- Version output now includes the cryptonym.
- Updated Pydantic to v1.7.3
- Updated httpx to v0.16.1
- Updated orjson to v3.4.6
- Updated the `servo.errors` module with numerous new error types.
- The `servo.events.run_event_handlers` method now always returns a list of
`EventResult` objects when `return_exceptions` is True. Exceptions are caught
and embedded in the `value` attribute.
- Exceptions raised by an event handler are decorated with a
`servo.events.EventResult` object on the `__event_result__` attribute.
- When an event is cancelled by a before event handler by raising a
`servo.errors.EventCancelledError`, an empty result list is now returned.
- The `servo.api.Mixin` class is now an abstract base class and requires the
implementation of the `api_client_options` method.
- Configuration of backoff/retry behaviors has been reimplemented for clarity
and simplicity.
- The `servo.assembly.Assembly` class now maintains a collection of servos
rather than a singleton.
- The optimizer settings are now part of the configuration.
- All CLI commands are now multi-servo aware and enabled.
- The `servo.Runner` class has been split into `servo.AssemblyRunner` and
`servo.ServoRunner` to support multi-servo configurations.
- The Docker image entry point is now multi-servo aware.
- Servos are now named. The default name is adopted from the Optimizer ID if
one is not directly configured.
- The top level `servo connectors` command now displays info about all available
connectors rather than those that are currently active. `servo show
connectors` now reports instance specific connector info.
- Migrated the `current*` family of methods off of model classes and into module
level functions be more Pythonic.

Removed

- The `duration` attribute of the Vegeta Connector configuration is now private
as the optimizer or operator always provide the value.
- The `servo.events.broadcast_event` method was removed as it was seldom used
and the functionality is easily replicated in downstream code.
- API client options including base URL, proxies, and timeouts are no longer
duplicated across connectors as an extra attribute.

Fixed

- Local versions are now resolved via the `pyproject.toml` file to accurately
reflect pre-release versioning and local work in progress.
- Exceptions are now chained within the Kubernetes Connector, ensuring that
traceback context is not lost.
- An invalid key was referenced during adjustment of Kubernetes container memory
request/limits.
- Scalar `servo.types.DataPoint` objects are now serialized for processing by
the optimizer service rather than raising an exception.
- The `ConnectorCLI` class now supports aliased connector instances.
- Test coverage gaps have been plugged throughout the CLI module.
- Scalar data points can now be handled by the CLI.
- Invalid keys in the `connectors` field of a config file will no longer
trigger an unhandled exception.
- Step values of range settings are now validated to ensure that a step of zero
is not configured.
- Setting values are now validated appropriately upon being changed. This
prevents invalid values from being externally applied to a running
optimization (e.g., an external deployment or manual change is made).
- Fixed exception in Prometheus mutltichecks due to unescpaed format
characters in interpolated Prometheus queries.
- Fixed connector lifecycle issue with Opsani Dev connector preventing use in
several of the CLI commands.
- Corrected an entry points discovery issue affecting the latest versions of
Python.

Fixed

- Containers are no longer accessed positionally by index instead of by name at
any time. This was resulting in broken adjustments when the Deployment
contained an init container, the main container was not the first container,
or during installation the Envoy proxy was injected at the beginning of the
container list instead of the end.

Fixed

- Initialize Kubernetes optimizations before taking a measurement. This ensures
that the Kubernetes Connector has an opportunity to set up the environment
before a measurement is taken that is reliant on the setup (e.g. all canaries
have been created).

Added

- Connectors can now be dynamically added and removed from the servo via the
`servo.servo.Servo` methods `add_connector` and `remove_connector`.
- Individual checks can now be run by ID or name via the
`servo.checks.BaseChecks.run_one` method.
- Developer Makefile tasks `format`, `lint`, and `test`.
- Introduced pre-commit hooks for enforcing style guides and engineering
standards.

Changed

- Code across the library is now referenced by package and module rather than
importing individual classes and functions. This reduces the amount of
boilerplate code in any given module and makes the code more accessible by
making implicit references explicit and unambiguous.
- Simplified `servo.logging.ProgressHandler` implementation with an asyncio
queue and producer/consumer pattern.
- Renamed `servo.checks.BaseChecks.run_` method to
`servo.checks.BaseChecks.run_all`.
- Renamed the `filter_` argument of check runners to `matching`.
- Millicore values are now serialized to strings as simple integers when evenly
divisible by 1000 (e.g., `str(Millicore(3000)) == "3"`).
- The canonical coding style for the project has been evolved to directly import
packages and modules instead of class and functions.

Fixed

- `servo show components` now includes the setting names instead of naked
values.
- Type resolution (used in eventing and checks) is now able to flexibly handle
arbitrary imports path and type aliases.
- Settlement time can now be supplied to adjust operations by the optimizer via
the `servo.types.Control` type.
- Before and after event handlers are no longer invoked with extraneous
arguments from the on event definition.