Deprecating regexp fields for json filter

- Replace regexp fields with source and target
- Added test for the new fields

lib/logstash/filters/json.rb

@@ -26,15 +26,50 @@ class LogStash::Filters::Json < LogStash::Filters::Base
   # already exists, it will be overridden.
   config /[A-Za-z0-9_@-]+/, :validate => :string
 
+  # Config for json is:
+  #
+  #     source => source_field
+  #
+  # For example, if you have json data in the @message field:
+  #
+  #     filter {
+  #       json {
+  #         source => "@message"
+  #       }
+  #     }
+  #
+  # The above would parse the xml from the @message field
+  config :source, :validate => :string
+
+  # Define target for placing the data
+  #
+  # for example if you want the data to be put in the 'doc' field:
+  #
+  #     filter {
+  #       json {
+  #         target => "doc"
+  #       }
+  #     }
+  #
+  # json in the value of the source field will be expanded into a
+  # datastructure in the "target" field.
+  # Note: if the "target" field already exists, it will be overridden
+  # Required
+  config :target, :validate => :string
+
   public
   def register
     @json = {}
 
     @config.each do |field, dest|
-      next if RESERVED.member?(field)
-
+      next if (RESERVED + ["source", "target"]).member?(field)
       @json[field] = dest
     end
+
+    if @source
+      @json[@source] = @target
+    end
+
   end # def register
 
   public

spec/filters/json.rb

@@ -4,7 +4,7 @@ require "logstash/filters/json"
 describe LogStash::Filters::Json do
   extend LogStash::RSpec
 
-  describe "parse @message into @fields" do
+  describe "parse @message into @fields ( deprecated check )" do
     config <<-CONFIG
       filter {
         json {
@@ -21,7 +21,7 @@ describe LogStash::Filters::Json do
     end
   end
 
-  describe "parse @message into a target field" do
+  describe "parse @message into a target field ( deprecated check )" do
     config <<-CONFIG
       filter {
         json {
@@ -38,7 +38,7 @@ describe LogStash::Filters::Json do
     end
   end
 
-  describe "tag invalid json" do
+  describe "tag invalid json ( deprecated check )" do
     config <<-CONFIG
       filter {
         json {
@@ -52,4 +52,58 @@ describe LogStash::Filters::Json do
       insist { subject.tags }.include?("_jsonparsefailure")
     end
   end
+
+  ## New tests
+
+  describe "parse @message into @fields" do
+    config <<-CONFIG
+      filter {
+        json {
+          # Parse @message as JSON, store the results in the 'data' field'
+          source => "@message"
+          target => "@fields"
+        }
+      }
+    CONFIG
+
+    sample '{ "hello": "world", "list": [ 1, 2, 3 ], "hash": { "k": "v" } }' do
+      insist { subject["hello"] } == "world"
+      insist { subject["list" ] } == [1,2,3]
+      insist { subject["hash"] } == { "k" => "v" }
+    end
+  end
+
+  describe "parse @message into a target field" do
+    config <<-CONFIG
+      filter {
+        json {
+          # Parse @message as JSON, store the results in the 'data' field'
+          source => "@message"
+          target => "data"
+        }
+      }
+    CONFIG
+
+    sample '{ "hello": "world", "list": [ 1, 2, 3 ], "hash": { "k": "v" } }' do
+      insist { subject["data"]["hello"] } == "world"
+      insist { subject["data"]["list" ] } == [1,2,3]
+      insist { subject["data"]["hash"] } == { "k" => "v" }
+    end
+  end
+
+  describe "tag invalid json" do
+    config <<-CONFIG
+      filter {
+        json {
+          # Parse @message as JSON, store the results in the 'data' field'
+          source => "@message"
+          target => "data"
+        }
+      }
+    CONFIG
+
+    sample "invalid json" do
+      insist { subject.tags }.include?("_jsonparsefailure")
+    end
+  end
 end