Ruby 3.2 compatibility and some minor tweaks.

.ruby-version

@@ -1 +1 @@
-2.1.7
+3.2.1

Rakefile

@@ -3,3 +3,4 @@ require 'rake/testtask'
 Rake::TestTask.new do |t|
   t.pattern = "test/*_test.rb"
 end
+task default: %i[test]

heroku-log-parser.gemspec

@@ -5,9 +5,9 @@ Gem::Specification.new do |s|
   s.name              = "heroku-log-parser"
   s.version           = HerokuLogParser::VERSION
   s.platform          = Gem::Platform::RUBY
-  s.author            = "Ryan Daigle"
+  s.authors            =["Ryan Daigle", "Florian Aßmann"]
   s.email             = ["[email protected]"]
-  s.homepage          = "https://github.com/rwdaigle/heroku-log-parser"
+  s.homepage          = "https://github.com/boof/heroku-log-parser"
   s.summary           = "Syslog message parser"
   s.description       = "Easily parse Heroku's syslog-based application log-stream"
 
@@ -18,7 +18,7 @@ Gem::Specification.new do |s|
   s.executables   = `git ls-files -- bin/*`.split("\n").map{ |f| File.basename(f) }
   s.require_paths = ["lib"]
 
-  if File.exists?('UPGRADING')
+  if File.exist?('UPGRADING')
     s.post_install_message = File.read("UPGRADING")
   end
 
@@ -49,4 +49,4 @@ Gem::Specification.new do |s|
   # s.add_development_dependency('fakeweb')
   # s.add_development_dependency('railties')
   # s.add_development_dependency('actionmailer')
-end
+end

lib/heroku-log-parser.rb

@@ -1,6 +1,14 @@
 require 'time'
 
 class HerokuLogParser
+  IS_NIL = "-"
+
+  COUNTING_FRAME_REGEX = /^(\d+) /
+  NEWLINE_REGEX = /\n/
+  # http://tools.ietf.org/html/rfc5424#page-8
+  # frame <prority>version time hostname <appname-missing> procid msgid [no structured data = '-'] msg
+  # 120 <40>1 2013-07-26T18:39:37.489572+00:00 host app web.11 - State changed from starting to up...
+  LINE_REGEX = /\<(\d+)\>(1) (\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d(?:\.\d+)?\+00:00) ([a-z0-9\-\_\.]+) ([a-z0-9\.-]+) ([a-z0-9\-\_\.]+) (\-) (.*)$/
 
   SYSLOG_KEYS = :priority, :syslog_version, :emitted_at, :hostname, :appname, :proc_id, :msg_id, :structured_data, :message
 
@@ -9,22 +17,14 @@ class << self
     def parse(data_str)
       events = []
       lines(data_str) do |line|
-        if(matching = line.match(line_regex))
-          events << event_data(matching)
-        end
+        matching = line.match LINE_REGEX
+        events << event_data(matching) if matching
       end
       events
     end
 
     protected
 
-    # http://tools.ietf.org/html/rfc5424#page-8
-    # frame <prority>version time hostname <appname-missing> procid msgid [no structured data = '-'] msg
-    # 120 <40>1 2013-07-26T18:39:37.489572+00:00 host app web.11 - State changed from starting to up...
-    def line_regex
-      @line_regex ||= /\<(\d+)\>(1) (\d\d\d\d-\d\d-\d\dT\d\d:\d\d:\d\d(?:\.\d+)?\+00:00) ([a-z0-9\-\_\.]+) ([a-z0-9\.-]+) ([a-z0-9\-\_\.]+) (\-) (.*)$/
-    end
-
     # Heroku's http log drains (https://devcenter.heroku.com/articles/labs-https-drains)
     # utilize octet counting framing (http://tools.ietf.org/html/draft-gerhards-syslog-plain-tcp-12#section-3.4.1)
     # for transmission of syslog messages over TCP. Properly parse and delimit
@@ -35,14 +35,14 @@ def line_regex
     def lines(data_str, &block)
       d = data_str
       while d && d.length > 0
-        if matching = d.match(/^(\d+) /) # if have a counting frame, use it
+        if matching = d.match(COUNTING_FRAME_REGEX) # if have a counting frame, use it
           num_bytes = matching[1].to_i
           frame_offset = matching[0].length
           line_end = frame_offset + num_bytes
           msg = d[frame_offset..(line_end-1)]
           yield msg
           d = d[line_end..d.length]
-        elsif matching = d.match(/\n/) # Newlines = explicit message delimiter
+        elsif matching = d.match(NEWLINE_REGEX) # Newlines = explicit message delimiter
           d = matching.post_match
         else
           STDERR.puts("Unable to parse: #{d}. Full line was: #{data_str.inspect}")
@@ -53,18 +53,18 @@ def lines(data_str, &block)
 
     # Heroku is missing the appname token, otherwise can treat as standard syslog format
     def event_data(matching)
-      event = {}
-      event[:priority] = matching[1].to_i
-      event[:syslog_version] = matching[2].to_i
-      event[:emitted_at] = nil?(matching[3]) ? nil : Time.parse(matching[3]).utc
-      event[:hostname] = interpret_nil(matching[4])
-      event[:appname] = interpret_nil(matching[5])
-      event[:proc_id] = interpret_nil(matching[6])
-      event[:msg_id] = interpret_nil(nil)
-      event[:structured_data] = interpret_nil(matching[7])
-      event[:message] = interpret_nil(matching[8])
-      event[:original] = matching[0]
-      event
+      {
+        priority: matching[1].to_i,
+        syslog_version: matching[2].to_i,
+        emitted_at: nil?(matching[3]) ? nil : Time.parse(matching[3]).utc,
+        hostname: interpret_nil(matching[4]),
+        appname: interpret_nil(matching[5]),
+        proc_id: interpret_nil(matching[6]),
+        msg_id: nil,
+        structured_data: interpret_nil(matching[7]),
+        message: interpret_nil(matching[8]),
+        original: matching[0],
+      }
     end
 
     private
@@ -74,7 +74,7 @@ def interpret_nil(val)
     end
 
     def nil?(val)
-      val == "-"
+      val == IS_NIL
     end
   end
 end