From 6921b470792bbed9a4322570758779ded8511aa9 Mon Sep 17 00:00:00 2001
From: Kenji Okimoto <okimoto@clear-code.com>
Date: Thu, 5 Jul 2018 09:33:31 +0900
Subject: [PATCH] Consider timezone when calculate timekey

Because the timestamp of the midnight cannot be divisible by 86400 in
localtime (JST). The timestamp of the midnight is divisible by 86400
only in UTC. Therefore we must consider offset from UTC in localtime.

For example, at `2018-07-04 01:23:23 +0900`:

If timekey is 86400 and path template is `/log/%Y%m%d.log`.
In previous version, extract path template to `/log/20180703.log`.
In this version, extract path template to `/log/20180704.log`.

Fix #1986

Signed-off-by: Kenji Okimoto <okimoto@clear-code.com>
---
 lib/fluent/plugin/output.rb  | 19 +++++++++++++------
 test/plugin/test_out_file.rb | 33 +++++++++++++++++++++++++++++++++
 2 files changed, 46 insertions(+), 6 deletions(-)

diff --git a/lib/fluent/plugin/output.rb b/lib/fluent/plugin/output.rb
index 3d64839264..feaa8b0c20 100644
--- a/lib/fluent/plugin/output.rb
+++ b/lib/fluent/plugin/output.rb
@@ -803,20 +803,17 @@ def metadata(tag, time, record)
           if !@chunk_key_time && !@chunk_key_tag
             @buffer.metadata()
           elsif @chunk_key_time && @chunk_key_tag
-            time_int = time.to_i
-            timekey = (time_int - (time_int % @buffer_config.timekey)).to_i
+            timekey = calculate_timekey(time)
             @buffer.metadata(timekey: timekey, tag: tag)
           elsif @chunk_key_time
-            time_int = time.to_i
-            timekey = (time_int - (time_int % @buffer_config.timekey)).to_i
+            timekey = calculate_timekey(time)
             @buffer.metadata(timekey: timekey)
           else
             @buffer.metadata(tag: tag)
           end
         else
           timekey = if @chunk_key_time
-                      time_int = time.to_i
-                      (time_int - (time_int % @buffer_config.timekey)).to_i
+                      calculate_timekey(time)
                     else
                       nil
                     end
@@ -825,6 +822,16 @@ def metadata(tag, time, record)
         end
       end
 
+      def calculate_timekey(time)
+        time_int = time.to_i
+        if @buffer_config.timekey_use_utc
+          (time_int - (time_int % @buffer_config.timekey)).to_i
+        else
+          offset = Time.at(time_int).utc_offset
+          (time_int - ((time_int + offset)% @buffer_config.timekey)).to_i
+        end
+      end
+
       def chunk_for_test(tag, time, record)
         require 'fluent/plugin/buffer/memory_chunk'
 
diff --git a/test/plugin/test_out_file.rb b/test/plugin/test_out_file.rb
index f68624effb..59d3080e42 100644
--- a/test/plugin/test_out_file.rb
+++ b/test/plugin/test_out_file.rb
@@ -557,6 +557,39 @@ def parse_system(text)
     check_gzipped_result(path, formatted_lines * 3)
   end
 
+  test 'append when JST' do
+    time = event_time("2011-01-02 03:14:15+09:00")
+    formatted_lines = %[2011-01-02T03:14:15+09:00\ttest\t{"a":1}\n] + %[2011-01-02T03:14:15+09:00\ttest\t{"a":2}\n]
+
+    write_once = ->(){
+      d = create_driver %[
+        path #{TMP_DIR}/out_file_test
+        compress gz
+        append true
+        <buffer>
+          timekey_use_utc false
+        </buffer>
+      ]
+      d.run(default_tag: 'test'){
+        d.feed(time, {"a"=>1})
+        d.feed(time, {"a"=>2})
+      }
+      d.instance.last_written_path
+    }
+
+    path = write_once.call
+    assert_equal "#{TMP_DIR}/out_file_test.20110102.log.gz", path
+    check_gzipped_result(path, formatted_lines)
+
+    path = write_once.call
+    assert_equal "#{TMP_DIR}/out_file_test.20110102.log.gz", path
+    check_gzipped_result(path, formatted_lines * 2)
+
+    path = write_once.call
+    assert_equal "#{TMP_DIR}/out_file_test.20110102.log.gz", path
+    check_gzipped_result(path, formatted_lines * 3)
+  end
+
   test '${chunk_id}' do
     time = event_time("2011-01-02 13:14:15 UTC")
     formatted_lines = %[2011-01-02T13:14:15Z\ttest\t{"a":1}\n] + %[2011-01-02T13:14:15Z\ttest\t{"a":2}\n]