ignore blank/empty json lines

Author: colinsurprenant

lib/logstash/codecs/json_lines.rb

@@ -59,11 +59,14 @@ def from_json_parse(json, &block)
 
   # legacy_parse uses the LogStash::Json class to deserialize json
   def legacy_parse(json, &block)
-    yield LogStash::Event.new(LogStash::Json.load(json))
+    # ignore empty/blank lines which LogStash::Json#load returns as nil
+    o = LogStash::Json.load(json)
+    yield(LogStash::Event.new(o)) if o
   rescue LogStash::Json::ParserError
     yield LogStash::Event.new("message" => json, "tags" => ["_jsonparsefailure"])
   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::JSONLines
+end

spec/codecs/json_lines_spec.rb

@@ -78,7 +78,6 @@
     end
 
     context "when json could not be parsed" do
-
       let(:message)    { "random_message\n" }
 
       it "add the failure tag" do
@@ -98,8 +97,26 @@
           expect(event['tags']).to include "_jsonparsefailure"
         end
       end
+    end
+
+    context "blank lines" do
+      let(:collector) { Array.new }
 
+      it "should ignore bare blanks" do
+        subject.decode("\n\n") do |event|
+          collector.push(event)
+        end
+        expect(collector.size).to eq(0)
+      end
+
+      it "should ignore in between blank lines" do
+        subject.decode("\n{\"a\":1}\n\n{\"b\":2}\n\n") do |event|
+          collector.push(event)
+        end
+        expect(collector.size).to eq(2)
+      end
     end
+
   end
 
   context "#encode" do