use Event#from_json if available

CHANGELOG.md

@@ -1,3 +1,6 @@
+## 2.1.0
+ - Backward compatible support for `Event#from_json` method https://github.com/logstash-plugins/logstash-codec-json/pull/21
+
 ## 2.0.4
  - Reduce the size of the gem by removing the vendor files
 

lib/logstash/codecs/json.rb

@@ -17,7 +17,6 @@
 class LogStash::Codecs::JSON < LogStash::Codecs::Base
   config_name "json"
 
-
   # The character encoding used in this codec. Examples include "UTF-8" and
   # "CP1252".
   #
@@ -29,43 +28,57 @@ class LogStash::Codecs::JSON < LogStash::Codecs::Base
   # For nxlog users, you may to set this to "CP1252".
   config :charset, :validate => ::Encoding.name_list, :default => "UTF-8"
 
-  public
   def register
     @converter = LogStash::Util::Charset.new(@charset)
     @converter.logger = @logger
   end
 
-  public
-  def decode(data)
-    data = @converter.convert(data)
-    begin
-      decoded = LogStash::Json.load(data)
-      if decoded.is_a?(Array)
-        decoded.each {|item| yield(LogStash::Event.new(item)) }
-      elsif decoded.is_a?(Hash)
-        yield LogStash::Event.new(decoded)
-      else
-        @logger.info? && @logger.info("JSON codec received a scalar instead of an Arary or Object!", :data => data)
-        yield LogStash::Event.new("message" => data, "tags" => ["_jsonparsefailure"])
-      end
-
-    rescue LogStash::Json::ParserError => e
-      @logger.info("JSON parse failure. Falling back to plain-text", :error => e, :data => data)
-      yield LogStash::Event.new("message" => data, "tags" => ["_jsonparsefailure"])
-    rescue StandardError => e
-      # This should NEVER happen. But hubris has been the cause of many pipeline breaking things
-      # If something bad should happen we just don't want to crash logstash here.
-      @logger.warn("An unexpected error occurred parsing input to JSON",
-                   :input => data,
-                   :message => e.message,
-                   :class => e.class.name,
-                   :backtrace => e.backtrace)
-    end
-  end # def decode
+  def decode(data, &block)
+    parse(@converter.convert(data), &block)
+  end
 
-  public
   def encode(event)
     @on_event.call(event, event.to_json)
-  end # def encode
+  end
+
+  private
+
+  def from_json_parse(json, &block)
+    LogStash::Event.from_json(json).each { |event| yield event }
+  rescue LogStash::Json::ParserError => e
+    @logger.error("JSON parse error, original data now in message field", :error => e, :data => json)
+    yield LogStash::Event.new("message" => json, "tags" => ["_jsonparsefailure"])
+  end
+
+  def legacy_parse(json, &block)
+    decoded = LogStash::Json.load(json)
+
+    case decoded
+    when Array
+      decoded.each {|item| yield(LogStash::Event.new(item)) }
+    when Hash
+      yield LogStash::Event.new(decoded)
+    else
+      @logger.error("JSON codec is expecting array or object/map", :data => json)
+      yield LogStash::Event.new("message" => json, "tags" => ["_jsonparsefailure"])
+    end
+  rescue LogStash::Json::ParserError => e
+    @logger.error("JSON parse failure. Falling back to plain-text", :error => e, :data => json)
+    yield LogStash::Event.new("message" => json, "tags" => ["_jsonparsefailure"])
+  rescue StandardError => e
+    # This should NEVER happen. But hubris has been the cause of many pipeline breaking things
+    # If something bad should happen we just don't want to crash logstash here.
+    @logger.warn(
+      "An unexpected error occurred parsing JSON data",
+      :data => json,
+      :message => e.message,
+      :class => e.class.name,
+      :backtrace => e.backtrace
+    )
+  end
+
+  # keep compatibility with all v2.x distributions. only in 2.3 will the Event#from_json method be introduced
+  # and we need to keep compatibility for all v2 releases.
+  alias_method :parse, LogStash::Event.respond_to?(:from_json) ? :from_json_parse : :legacy_parse
 
-end # class LogStash::Codecs::JSON
+end

logstash-codec-json.gemspec

@@ -1,17 +1,17 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-codec-json'
-  s.version         = '2.0.4'
+  s.version         = '2.1.0'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "This codec may be used to decode (via inputs) and encode (via outputs) full JSON messages"
   s.description     = "This gem is a logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/plugin install gemname. This gem is not a stand-alone program"
   s.authors         = ["Elastic"]
   s.email           = 'info@elastic.co'
   s.homepage        = "http://www.elastic.co/guide/en/logstash/current/index.html"
-  s.require_paths = ["lib"]
+  s.require_paths   = ["lib"]
 
   # Files
-  s.files = Dir['lib/**/*','spec/**/*','vendor/**/*','*.gemspec','*.md','CONTRIBUTORS','Gemfile','LICENSE','NOTICE.TXT']
+  s.files = Dir['lib/**/*','spec/**/*','*.gemspec','*.md','CONTRIBUTORS','Gemfile','LICENSE','NOTICE.TXT']
 
   # Tests
   s.test_files = s.files.grep(%r{^(test|spec|features)/})