Add support for parsing service check and event datagrams.

lib/statsd/instrument/client.rb

@@ -1,6 +1,7 @@
 # frozen_string_literal: true
 
 require 'statsd/instrument/datagram'
+require 'statsd/instrument/dogstatsd_datagram'
 require 'statsd/instrument/datagram_builder'
 require 'statsd/instrument/statsd_datagram_builder'
 require 'statsd/instrument/dogstatsd_datagram_builder'

lib/statsd/instrument/datagram.rb

@@ -1,6 +1,6 @@
 # frozen_string_literal: true
 
-# The Datagram class parses and inspects a StatsD datagrans
+# The Datagram class parses and inspects a StatsD datagrams
 #
 # @note This class is part of the new Client implementation that is intended
 #   to become the new default in the next major release of this library.
@@ -72,7 +72,6 @@ def eql?(other)
     \n? # In some implementations, the datagram may include a trailing newline.
     \z
   }x
-  private_constant :PARSER
 
   def parsed_datagram
     @parsed ||= if (match_info = PARSER.match(@source))

lib/statsd/instrument/dogstatsd_datagram.rb

@@ -0,0 +1,88 @@
+# frozen_string_literal: true
+
+# The Datagram class parses and inspects a StatsD datagrams
+#
+# @note This class is part of the new Client implementation that is intended
+#   to become the new default in the next major release of this library.
+class StatsD::Instrument::DogStatsDDatagram < StatsD::Instrument::Datagram
+  def name
+    @name ||= case type
+    when :_e then parsed_datagram[:name].gsub('\n', "\n")
+    else super
+    end
+  end
+
+  def value
+    @value ||= case type
+    when :_sc then Integer(parsed_datagram[:value])
+    when :_e then parsed_datagram[:value].gsub('\n', "\n")
+    else super
+    end
+  end
+
+  def hostname
+    parsed_datagram[:hostname]
+  end
+
+  def timestamp
+    Time.at(Integer(parsed_datagram[:timestamp])).utc
+  end
+
+  def aggregation_key
+    parsed_datagram[:aggregation_key]
+  end
+
+  def source_type_name
+    parsed_datagram[:source_type_name]
+  end
+
+  def priority
+    parsed_datagram[:priority]
+  end
+
+  def alert_type
+    parsed_datagram[:alert_type]
+  end
+
+  def message
+    parsed_datagram[:message]
+  end
+
+  protected
+
+  def parsed_datagram
+    @parsed ||= if (match_info = PARSER.match(@source))
+      match_info
+    else
+      raise ArgumentError, "Invalid DogStatsD datagram: #{@source}"
+    end
+  end
+
+  SERVICE_CHECK_PARSER = %r{
+    \A
+    (?<type>_sc)\|(?<name>[^\|]+)\|(?<value>\d+)
+    (?:\|h:(?<hostname>[^\|]+))?
+    (?:\|d:(?<timestamp>\d+))?
+    (?:\|\#(?<tags>(?:[^\|,]+(?:,[^\|,]+)*)))?
+    (?:\|m:(?<message>[^\|]+))?
+    \n? # In some implementations, the datagram may include a trailing newline.
+    \z
+  }x
+
+  # |k:my-key|p:low|s:source|t:success|
+  EVENT_PARSER = %r{
+    \A
+    (?<type>_e)\{\d+\,\d+\}:(?<name>[^\|]+)\|(?<value>[^\|]+)
+    (?:\|h:(?<hostname>[^\|]+))?
+    (?:\|d:(?<timestamp>\d+))?
+    (?:\|k:(?<aggregation_key>[^\|]+))?
+    (?:\|p:(?<priority>[^\|]+))?
+    (?:\|s:(?<source_type_name>[^\|]+))?
+    (?:\|t:(?<alert_type>[^\|]+))?
+    (?:\|\#(?<tags>(?:[^\|,]+(?:,[^\|,]+)*)))?
+    \n? # In some implementations, the datagram may include a trailing newline.
+    \z
+  }x
+
+  PARSER = Regexp.union(StatsD::Instrument::Datagram::PARSER, SERVICE_CHECK_PARSER, EVENT_PARSER)
+end

lib/statsd/instrument/dogstatsd_datagram_builder.rb

@@ -5,6 +5,10 @@
 class StatsD::Instrument::DogStatsDDatagramBuilder < StatsD::Instrument::DatagramBuilder
   unsupported_datagram_types :kv
 
+  def self.datagram_class
+    StatsD::Instrument::DogStatsDDatagram
+  end
+
   def latency_metric_type
     :d
   end

test/dogstatsd_datagram_builder_test.rb

@@ -11,20 +11,57 @@ def test_raises_on_unsupported_metrics
     assert_raises(NotImplementedError) { @datagram_builder.kv('foo', 10, nil, nil) }
   end
 
-  def test_service_check
-    assert_equal '_sc|service|0', @datagram_builder._sc('service', :ok)
+  def test_simple_service_check
+    datagram = @datagram_builder._sc('service', :ok)
+    assert_equal '_sc|service|0', datagram
+    parsed_datagram = StatsD::Instrument::DogStatsDDatagramBuilder.datagram_class.new(datagram)
+    assert_equal :_sc, parsed_datagram.type
+    assert_equal 'service', parsed_datagram.name
+    assert_equal 0, parsed_datagram.value
+  end
+
+  def test_complex_service_check
     datagram = @datagram_builder._sc('service', :warning, timestamp: Time.parse('2019-09-30T04:22:12Z'),
       hostname: 'localhost', tags: { foo: 'bar|baz' }, message: 'blah')
     assert_equal "_sc|service|1|h:localhost|d:1569817332|#foo:barbaz|m:blah", datagram
+
+    parsed_datagram = StatsD::Instrument::DogStatsDDatagramBuilder.datagram_class.new(datagram)
+    assert_equal :_sc, parsed_datagram.type
+    assert_equal 'service', parsed_datagram.name
+    assert_equal 1, parsed_datagram.value
+    assert_equal 'localhost', parsed_datagram.hostname
+    assert_equal Time.parse('2019-09-30T04:22:12Z'), parsed_datagram.timestamp
+    assert_equal ["foo:barbaz"], parsed_datagram.tags
+    assert_equal 'blah', parsed_datagram.message
   end
 
-  def test_event
-    assert_equal '_e{5,5}:hello|world', @datagram_builder._e('hello', "world")
+  def test_simple_event
+    datagram = @datagram_builder._e('hello', "world")
+    assert_equal '_e{5,5}:hello|world', datagram
 
+    parsed_datagram = StatsD::Instrument::DogStatsDDatagramBuilder.datagram_class.new(datagram)
+    assert_equal :_e, parsed_datagram.type
+    assert_equal 'hello', parsed_datagram.name
+    assert_equal 'world', parsed_datagram.value
+  end
+
+  def test_complex_event
     datagram = @datagram_builder._e("testing", "with\nnewline", timestamp: Time.parse('2019-09-30T04:22:12Z'),
       hostname: 'localhost', aggregation_key: 'my-key', priority: 'low', source_type_name: 'source',
       alert_type: 'success', tags: { foo: 'bar|baz' })
     assert_equal '_e{7,13}:testing|with\\nnewline|h:localhost|d:1569817332|k:my-key|' \
       'p:low|s:source|t:success|#foo:barbaz', datagram
+
+    parsed_datagram = StatsD::Instrument::DogStatsDDatagramBuilder.datagram_class.new(datagram)
+    assert_equal :_e, parsed_datagram.type
+    assert_equal 'testing', parsed_datagram.name
+    assert_equal "with\nnewline", parsed_datagram.value
+    assert_equal 'localhost', parsed_datagram.hostname
+    assert_equal Time.parse('2019-09-30T04:22:12Z'), parsed_datagram.timestamp
+    assert_equal ["foo:barbaz"], parsed_datagram.tags
+    assert_equal "my-key", parsed_datagram.aggregation_key
+    assert_equal "low", parsed_datagram.priority
+    assert_equal "source", parsed_datagram.source_type_name
+    assert_equal "success", parsed_datagram.alert_type
   end
 end