From 9c0005ef67bfae7d647e8d54e4fb668b807c2963 Mon Sep 17 00:00:00 2001
From: Daijiro Fukuda <fukuda@clear-code.com>
Date: Tue, 21 Mar 2023 11:12:21 +0900
Subject: [PATCH] Make sure JSON parser returns Hash

Record must be Hash.

Signed-off-by: Daijiro Fukuda <fukuda@clear-code.com>
---
 lib/fluent/plugin/parser_json.rb |  3 +++
 test/plugin/test_parser_json.rb  | 26 ++++++++++++++++++++++++++
 2 files changed, 29 insertions(+)

diff --git a/lib/fluent/plugin/parser_json.rb b/lib/fluent/plugin/parser_json.rb
index 840f6a963c..641663e596 100644
--- a/lib/fluent/plugin/parser_json.rb
+++ b/lib/fluent/plugin/parser_json.rb
@@ -71,6 +71,9 @@ def configure_json_parser(name)
 
       def parse(text)
         record = @load_proc.call(text)
+        # Sometimes the parser returns String, not Hash.
+        # Ex. Oj.load('"hoge"') => "hoge"
+        raise @error_class unless record.is_a?(Hash)
         time = parse_time(record)
         if @execute_convert_values
           time, record = convert_values(time, record)
diff --git a/test/plugin/test_parser_json.rb b/test/plugin/test_parser_json.rb
index 19c45402d1..fb8947581f 100644
--- a/test/plugin/test_parser_json.rb
+++ b/test/plugin/test_parser_json.rb
@@ -135,4 +135,30 @@ def test_yajl_parse_io_with_buffer_smaller_than_input
       end
     end
   end
+
+  sub_test_case "various record pattern" do
+    data("Only string", { record: '"message"', exepected: nil }, keep: true)
+    data("Only string without quaot", { record: "message", exepected: nil }, keep: true)
+    data("Only number", { record: "0", exepected: nil }, keep: true)
+    def test_oj(data)
+      @parser.configure('json_parser' => "oj")
+      @parser.instance.parse(data[:record]) { |time, record|
+        assert_equal(data[:expected], record)
+      }
+    end
+
+    def test_yajl(data)
+      @parser.configure('json_parser' => "yajl")
+      @parser.instance.parse(data[:record]) { |time, record|
+        assert_equal(data[:expected], record)
+      }
+    end
+
+    def test_json(json)
+      @parser.configure('json_parser' => "json")
+      @parser.instance.parse(data[:record]) { |time, record|
+        assert_equal(data[:expected], record)
+      }
+    end
+  end
 end