validate if timkey is less than equal 0

Signed-off-by: Yuta Iwama <ganmacs@gmail.com>

lib/fluent/plugin/output.rb

@@ -310,6 +310,9 @@ def configure(conf)
             Fluent::Timezone.validate!(@buffer_config.timekey_zone)
             @timekey_zone = @buffer_config.timekey_use_utc ? '+0000' : @buffer_config.timekey_zone
             @timekey = @buffer_config.timekey
+            if @timekey <= 0
+              raise Fluent::ConfigError, "timekey should be greater than 0. current timekey: #{@timekey}"
+            end
             @timekey_use_utc = @buffer_config.timekey_use_utc
             @offset = Fluent::Timezone.utc_offset(@timekey_zone)
             @calculate_offset = @offset.respond_to?(:call) ? @offset : nil

test/plugin/test_output.rb

@@ -868,6 +868,18 @@ def waiting(seconds)
     end
   end
 
+  test 'raises an error if timekey is less than equal 0' do
+    i = create_output(:delayed)
+    assert_raise Fluent::ConfigError.new('timekey should be greater than 0. current timekey: 0.0') do
+      i.configure(config_element('ROOT','',{},[config_element('buffer', 'time', { "timekey" => 0 })]))
+    end
+
+    i = create_output(:delayed)
+    assert_raise Fluent::ConfigError.new('timekey should be greater than 0. current timekey: -1.0') do
+      i.configure(config_element('ROOT','',{},[config_element('buffer', 'time', { "timekey" => -1 })]))
+    end
+  end
+
   sub_test_case 'sync output feature' do
     setup do
       @i = create_output(:sync)