Normalize Config Support Mixin

This gem can be included in any LogStash::Plugin, and will provide utilities methods that can be used by the plugins to extract and normalize configs.

1. Add version ~>1.0 of this gem as a runtime dependency of your Logstash plugin's gemspec:

   Gem::Specification.new do |s|
     # ...
   
     s.add_runtime_dependency 'logstash-mixin-normalize_config_support', '~>1.0'
   end

2. In your plugin code, require this library and include it into your plugin class that already inherits LogStash::Plugin:

   require 'logstash/plugin_mixins/normalize_config_support'
   
   class LogStash::Inputs::Foo < Logstash::Inputs::Base
     include LogStash::PluginMixins::NormalizeConfigSupport
   
     # ...
   end

3. Use the provided normalize_config method to normalize a configuration and to produce a canonical value for it. It currently supports the following normalizers:

   • with_deprecated_mapping: Map one or more deprecated configs to the canonical config
   • with_deprecated_alias: Wholly-alias a deprecated config to the canonical config

   def register
     # ...
     @ssl_verification_mode = normalize_config(:ssl_verification_mode) do |normalize|
        normalize.with_deprecated_mapping(:ssl_verify_mode) do |ssl_verify_mode|
           case ssl_verify_mode
           when "none"       then "none"
           when "peer"       then "certificate"
           when "force_peer" then "full"
           else fail(LogStash::ConfigurationError, "Unsupported value #{ssl_verify_mode} for deprecated option `ssl_verify_mode`")
        end
     end
   
     @ssl_cipher_suites = normalize_config(:ssl_cipher_suites) do |normalize|
        normalize.with_deprecated_alias(:cipher_suites)
     end
   
     @ssl_supported_protocols = normalize_config(:ssl_supported_protocols) do |normalize|
        normalize.with_deprecated_mapping(:tls_min_version, :tls_max_version) do |tls_min, tls_max|
           TLS.get_supported(tls_min..tls_max).map(&:name)
        end
     end
   end

This gem:

• MUST NOT introduce additional runtime dependencies