expose DEFAULT_LOGGER and remove nil/null support

logstash-core-event-java/spec/event_spec.rb

@@ -149,7 +149,7 @@ describe LogStash::Event do
   context "logger" do
 
     let(:logger) { double("Logger") }
-    after(:each) {  LogStash::Event.logger = nil }
+    after(:each) {  LogStash::Event.logger = LogStash::Event::DEFAULT_LOGGER }
 
     # the following 2 specs are using both a real module (DummyLogger)
     # and a mock. both tests are needed to make sure the implementation
@@ -163,7 +163,7 @@ describe LogStash::Event do
 
     it "should set logger using a mock" do
       LogStash::Event.logger = logger
-      expect(logger).to receive(:warn)
+      expect(logger).to receive(:warn).once
       LogStash::Event.new(TIMESTAMP => "invalid timestamp")
     end
 
@@ -174,7 +174,7 @@ describe LogStash::Event do
       LogStash::Event.new(TIMESTAMP => "invalid timestamp")
 
       # then unset
-      LogStash::Event.logger = nil
+      LogStash::Event.logger = LogStash::Event::DEFAULT_LOGGER
       expect(logger).to receive(:warn).never
       # this will produce a log line in stdout by the Java Event
       LogStash::Event.new(TIMESTAMP => "ignore this log")

logstash-core-event-java/src/main/java/com/logstash/Event.java

@@ -30,6 +30,9 @@ public class Event implements Cloneable, Serializable {
 
     private static final Logger DEFAULT_LOGGER = new StdioLogger();
     private transient final ObjectMapper mapper = new ObjectMapper();
+
+    // logger is static since once set there is no point in changing it at runtime
+    // for other reasons than in tests/specs.
     private transient static Logger logger = DEFAULT_LOGGER;
 
     public Event()
@@ -249,7 +252,9 @@ public class Event implements Cloneable, Serializable {
         }
     }
 
+    // Event.logger is static since once set there is no point in changing it at runtime
+    // for other reasons than in tests/specs.
     public static void setLogger(Logger logger) {
-        Event.logger = (logger == null) ? DEFAULT_LOGGER : logger;
+        Event.logger = logger;
     }
 }

logstash-core-event-java/src/main/java/com/logstash/ext/JrubyEventExtLibrary.java

@@ -30,6 +30,7 @@ public class JrubyEventExtLibrary implements Library {
         clazz.setConstant("TIMESTAMP", runtime.newString(Event.TIMESTAMP));
         clazz.setConstant("TIMESTAMP_FAILURE_TAG", runtime.newString(Event.TIMESTAMP_FAILURE_TAG));
         clazz.setConstant("TIMESTAMP_FAILURE_FIELD", runtime.newString(Event.TIMESTAMP_FAILURE_FIELD));
+        clazz.setConstant("DEFAULT_LOGGER", runtime.getModule("Cabin").getClass("Channel").callMethod("get", runtime.getModule("LogStash")));
         clazz.defineAnnotatedMethods(RubyEvent.class);
         clazz.defineAnnotatedConstants(RubyEvent.class);
     }
@@ -287,10 +288,12 @@ public class JrubyEventExtLibrary implements Library {
             return new JrubyTimestampExtLibrary.RubyTimestamp(context.getRuntime(), this.event.getTimestamp());
         }
 
+        // set a new logger for all Event instances
+        // there is no point in changing it at runtime for other reasons than in tests/specs.
         @JRubyMethod(name = "logger=", required = 1, meta = true)
         public static IRubyObject ruby_set_logger(ThreadContext context, IRubyObject recv, IRubyObject value)
         {
-            Event.setLogger(value.isNil() ? null : new ProxyLogger((RubyObject)value));
+            Event.setLogger(new ProxyLogger((RubyObject)value));
             return value;
         }
     }

logstash-core-event/lib/logstash/event.rb

@@ -63,6 +63,9 @@ class LogStash::Event
   MIN_FLOAT_BEFORE_SCI_NOT = 0.0001
   MAX_FLOAT_BEFORE_SCI_NOT = 1000000000000000.0
 
+  DEFAULT_LOGGER = Cabin::Channel.get(LogStash)
+  @@logger = DEFAULT_LOGGER
+
   def initialize(data = {})
     @cancelled = false
     @data = data
@@ -243,6 +246,9 @@ class LogStash::Event
     raise DeprecatedMethod
   end
 
+  # set a new logger for all Event instances
+  # there is no point in changing it at runtime for other reasons than in tests/specs.
+  # @param logger [Cabin::Channel] logger instance that will be used by all Event instances
   def self.logger=(logger)
     @@logger = logger
   end
@@ -250,7 +256,7 @@ class LogStash::Event
   private
 
   def logger
-    @@logger ||= Cabin::Channel.get(LogStash)
+    @@logger
   end
 
   def init_timestamp(o)

logstash-core-event/spec/logstash/event_spec.rb

@@ -348,7 +348,7 @@ describe LogStash::Event do
         LogStash::Event.new("@timestamp" => 666)
 
         # reset logger to default
-        LogStash::Event.logger = nil
+        LogStash::Event.logger = LogStash::Event::DEFAULT_LOGGER
       end
 
       it "should tag for invalid string format" do
@@ -365,7 +365,7 @@ describe LogStash::Event do
         LogStash::Event.new("@timestamp" => "foo")
 
         # reset logger to default
-        LogStash::Event.logger = nil
+        LogStash::Event.logger = LogStash::Event::DEFAULT_LOGGER
       end
     end