Add host to @metadata like path, in case event also contains field of same name

Fixes #136

Author: jimmyjones2

CHANGELOG.md

@@ -1,3 +1,5 @@
+## 3.1.1
+  - Add host to @metadata
 ## 3.1.0
   - Use native `--path.data` for Logstash 5.0 for sincedb files.
 ## 3.0.3

lib/logstash/inputs/file.rb

@@ -314,6 +314,7 @@ def run(queue)
   end # def run
 
   def post_process_this(event)
+    event.set("[@metadata][host]", @host)
     event.set("host", @host) if !event.include?("host")
     decorate(event)
     @queue << event

logstash-input-file.gemspec

@@ -1,7 +1,7 @@
 Gem::Specification.new do |s|
 
   s.name            = 'logstash-input-file'
-  s.version         = '3.1.0'
+  s.version         = '3.1.1'
   s.licenses        = ['Apache License (2.0)']
   s.summary         = "Stream events from files."
   s.description     = "This gem is a Logstash plugin required to be installed on top of the Logstash core pipeline using $LS_HOME/bin/logstash-plugin install gemname. This gem is not a stand-alone program"

spec/inputs/file_spec.rb

@@ -122,9 +122,11 @@
 
       insist { events[0].get("path") } == "my_path"
       insist { events[0].get("host") } == "my_host"
+      insist { events[0].get("[@metadata][host]") } == "#{Socket.gethostname.force_encoding(Encoding::UTF_8)}"
 
       insist { events[1].get("path") } == "#{tmpfile_path}"
       insist { events[1].get("host") } == "#{Socket.gethostname.force_encoding(Encoding::UTF_8)}"
+      insist { events[1].get("[@metadata][host]") } == "#{Socket.gethostname.force_encoding(Encoding::UTF_8)}"
     end
 
     context "when sincedb_path is an existing directory" do