class SemanticLogger::Appender::SplunkHttp

https://docs.splunk.com/Documentation/Splunk/latest/Data/FormateventsforHTTPEventCollector
For splunk format requirements see:

Returns [String] JSON to send to Splunk.

def call(log, logger)
  h = SemanticLogger::Formatters::Raw.new(time_format: :seconds).call(log, logger)
  h.delete(:host)
  message = {
    source: logger.application,
    host:   logger.host,
    time:   h.delete(:time),
    event:  h
  }
  message[:sourcetype]  = source_type if source_type
  message[:index]       = index if index
  message.to_json
end

The Proc must return true or false.
Proc: Only include log messages where the supplied Proc returns true
regular expression. All other messages will be ignored.
RegExp: Only include log messages where the class name matches the supplied.
filter: [Regexp|Proc]

Default: Use the built-in formatter (See: #call)
the output from this appender
An instance of a class that implements #call, or a Proc to be used to format
formatter: [Object|Proc]

Default: SemanticLogger.default_level
Override the log level for this appender.
level: [:trace | :debug | :info | :warn | :error | :fatal]

ssl_version, use_ssl, verify_callback, verify_depth and verify_mode.
ca_file, ca_path, cert, cert_store, ciphers, key, open_timeout, read_timeout, ssl_timeout,
Specific SSL options: For more details see NET::HTTP.start
ssl: [Hash]

Default: true
Splunk supports HTTP Compression, enable by default.
compress: [true|false]

Default: SemanticLogger.host
Name of this host to appear in log messages.
host: [String]

Default: SemanticLogger.application
Name of this application to appear in log messages.
application: [String]

verify_mode will default: OpenSSL::SSL::VERIFY_PEER
Example: https://example.com
To enable SSL include https in the URL.
Example: http://example.com
Valid URL to post to.
url: [String]

Optional: Name of a valid index for this message in Splunk.
index: [String]

Optional: Source type to display in Splunk
source_type: [String]

Mandatory.
Token created in Splunk for this HTTP Appender
token: [String]
Parameters:

Create Splunk appender over persistent HTTP(S)

def initialize(token: nil,
               source_type: nil,
               index: nil,
               compress: true,
               **args,
               &block)
  @source_type = source_type
  @index       = index
  super(compress: compress, **args, &block)
  # Put splunk auth token in the header of every HTTP post.
  @header["Authorization"] = "Splunk #{token}"
end