Use Yajl as the json parser, in order to accept malformed json messages

fluent-plugin-dynatrace.gemspec

@@ -25,6 +25,7 @@ Gem::Specification.new do |gem|
   gem.required_ruby_version = '>= 2.7.0'
 
   gem.add_runtime_dependency 'fluentd', ['>= 0.14.22', '< 2']
+  gem.add_runtime_dependency 'yajl-ruby', ['~> 1.4', '>= 1.4.3']
   gem.add_development_dependency 'bundler', ['>= 2', '<3']
   gem.add_development_dependency 'rake', '13.1.0'
   gem.add_development_dependency 'rubocop', '1.59.0'

lib/fluent/plugin/dynatrace_constants.rb

@@ -20,7 +20,7 @@ module Plugin
     class DynatraceOutputConstants
       # The version of the Dynatrace output plugin
       def self.version
-        '0.2.1'
+        '0.2.2'
       end
     end
   end

lib/fluent/plugin/out_dynatrace.rb

@@ -16,6 +16,7 @@
 
 require 'fluent/plugin/output'
 require 'net/http'
+require 'yajl'
 require_relative 'dynatrace_constants'
 
 module Fluent
@@ -155,7 +156,7 @@ def send_records(records)
 
       def serialize(records)
         log.on_trace { log.trace('#serialize') }
-        body = "#{records.to_json.chomp}\n"
+        body = "#{Yajl.dump(records)}\n"
         log.on_trace { log.trace("#serialize body length #{body.length}") }
         body
       end

test/plugin/out_dynatrace_test.rb

@@ -212,22 +212,26 @@ def create_driver(conf = config)
   end
 
   sub_test_case 'tests for #write' do
-    test 'Write all records as a JSON array' do
+    test 'write all records as a JSON array' do
       d = create_driver
       t = event_time('2016-06-10 19:46:32 +0900')
+      malformed_json_message = "This is a malformed json message V\x92\xA1\u000F\xF0ܱ\u0013,\x82"
       d.run do
         d.feed('tag', t, { 'message' => 'this is a test message', 'amount' => 53 })
         d.feed('tag', t, { 'message' => 'this is a second test message', 'amount' => 54 })
+        d.feed('tag', t, { 'message' => malformed_json_message, 'amount' => 54 })
       end
 
-      assert_equal 2, d.instance.agent.result.data.length
+      assert_equal 3, d.instance.agent.result.data.length
 
       content = d.instance.agent.result.data[0]
+      malformed_json_content = d.instance.agent.result.data[2]
 
       assert_equal "fluent-plugin-dynatrace/#{Fluent::Plugin::DynatraceOutputConstants.version}",
                    d.instance.agent.result.headers['user-agent']
       assert_equal content['message'], 'this is a test message'
       assert_equal content['amount'], 53
+      assert_equal malformed_json_content['message'], malformed_json_message
     end
 
     test 'should not export an empty payload' do