Syslog::Stream

Parse streams of RFC5424 Syslog messages

Installation

Add this line to your application's Gemfile:

gem "syslog-stream"

And then execute:

bundle

Or install it using gem(1):

gem install syslog-stream

Usage

Syslog::Stream::OctetCountingFraming.new should be able to accept any IO object.

require "stringio"
require "syslog/stream"

io = StringIO.new(
  '176 <165>1 2003-10-11T22:14:15.003Z mymachine.example.com evntslog - ID47 '\
  '[exampleSDID@32473 iut="3" eventSource="Application" eventID="1011"] An '\
  'application event log entry...181 <165>1 2003-10-11T22:14:16.003Z '\
  'mymachine.example.com evntslog - ID48 [exampleSDID@32473 iut="3" '\
  'eventSource="Application" eventID="1012"] Another application event log '\
  'entry...',
)

stream = Syslog::Stream.new(Syslog::Stream::OctetCountingFraming.new(io))

stream.messages do |message|
  # The values below are for the first yield to this block. This block will be
  # yielded to, two times in total: Once for each messsage.
  message.prival          #=> 165
  message.facility        #=> 20
  message.severity        #=> 5
  message.version         #=> 1
  message.timestamp       #=> 2003-10-11 22:14:15 UTC
  message.timestamp.class #=> Time
  message.hostname        #=> "mymachine.example.com"
  message.app_name        #=> "evntslog"
  message.procid          #=> nil
  message.structured_data #=> [#<struct StructuredDataElement
  # id="exampleSDID@32473"@71, params={"iut"=>"3", "eventSource"=>"Application",
  # "eventID"=>"1011"}>]
  message.msg             #=> "An application event log entry..."
end

Parsing streams received via Heroku HTTPS log drains

The cloud application platform Heroku allows it's users to register log drains that receive Syslog formatted application log messages over HTTPS. As outlined in Heroku's documentation on HTTPS Log Drains, these messages do not fully conform to RFC5424:

“application/logplex-1” does not conform to RFC5424. It leaves out STRUCTURED-DATA but does not replace it with a NILVALUE.

RFC5424 requires STRUCTURED-DATA to consist of either one NILVALUE or one or more SD-ELEMENTs.

In order to parse Syslog streams received via Heroku HTTPS log drains, Syslog::Stream needs to be instantiated with a parser that allows missing STRUCTURE-DATA:

parser = Syslog::Parser.new(allow_missing_structured_data: true)

io = StringIO.new

stream = Syslog::Stream.new(
  Syslog::Stream::OctetCountingFraming.new(io),
  parser: parser,
)

syslog-stream

Development

Runtime

Syslog::Stream

Installation

Usage

Parsing streams received via Heroku HTTPS log drains