This is so levels like warn and error can be used to exclude info or warn messages. Additionally there is a reasonable refactoring of logging moving the log config options to the logging key because there are a significant number of log options now. This also decouples the expvars and pprof handlers from the log level, and they are now configured by server.enable_expvars and server.enable_pprof at any logging level.
This change implements yamllint and adjusts all yaml files to abide by our linting setup. This excludes config.template.yml as this will be done in an alternate commit.
* [FEATURE] File Secret Loading
* add a validator for secrets
* run the secrets validator before the main config validator
* only allow a secret to be defined in one of: config, env, file env
* remove LF if found in file
* update configuration before main config validation
* fix unit tests
* implement secret testing
* refactor the secrets validator
* make check os agnostic
* update docs
* add warning when user attempts to use ENV instead of ENV file
* discourage ENV in docs
* update config template
* oxford comma
* apply suggestions from code review
* rename Validate to ValidateConfiguration
* add k8s example
* add deprecation notice in docs and warning
* style changes
