add serilog support

Author: yaron-idan

lib/fluent/plugin/filter_kubernetes_log_level.rb

@@ -31,17 +31,17 @@ def configure(conf)
 
       def level_to_num(level)
         case level
-        when 'trace'
+        when 'trace', 'Verbose'
           10
-        when 'debug'
+        when 'debug', 'Debug'
           20
-        when 'info'
+        when 'info', 'Information'
           30
-        when 'warning'
+        when 'warning', 'Warning'
           40
-        when 'error'
+        when 'error', 'Error'
           50
-        when 'fatal'
+        when 'fatal', 'Fatal'
           60
         else
           0

test/plugin/test_filter_kubernetes_log_level.rb

@@ -27,6 +27,16 @@ class KubernetesLogLevelFilterTest < Test::Unit::TestCase
     @expected_static_warning_default = [{
       'level' => 'warning'
     }]
+
+    @expected_warning_serilog = [{
+      'level'      => 'Warning',
+      'kubernetes' => {
+        'labels' => {
+          'logging-level' => 'Warning'
+        }
+      }
+    }]
+
   end
 
   CONFIG = %[
@@ -69,4 +79,8 @@ def test_log_level_lower_then_threshold
   def test_static_log
     assert_equal @expected_static_warning_default, filter({"level"=>"warning"})
   end
+
+  def test_serilog_structure
+    assert_equal @expected_warning_serilog, filter({"level"=>"Warning", "kubernetes"=>{"labels"=>{"logging-level"=>"Warning"}}})
+  end
 end