refactoring to allows unit testing of logstash event creation

Author: wiibaa

lib/logstash/inputs/log4j.rb

@@ -59,41 +59,45 @@ def register
  @logger.info("Log4j input")
  end # def register
 
+ public
+ def create_event(log4j_obj)
+ # NOTE: log4j_obj is org.apache.log4j.spi.LoggingEvent
+ event = LogStash::Event.new("message" => log4j_obj.getRenderedMessage)
+ event["path"] = log4j_obj.getLoggerName
+ event["priority"] = log4j_obj.getLevel.toString
+ event["logger_name"] = log4j_obj.getLoggerName
+ event["thread"] = log4j_obj.getThreadName
+ event["class"] = log4j_obj.getLocationInformation.getClassName
+ event["file"] = log4j_obj.getLocationInformation.getFileName + ":" + log4j_obj.getLocationInformation.getLineNumber
+ event["method"] = log4j_obj.getLocationInformation.getMethodName
+ event["NDC"] = log4j_obj.getNDC if log4j_obj.getNDC
+ event["stack_trace"] = log4j_obj.getThrowableStrRep.to_a.join("\n") if log4j_obj.getThrowableInformation
+
+ # Add the MDC context properties to event
+ if log4j_obj.getProperties
+ log4j_obj.getPropertyKeySet.each do |key|
+ event[key] = log4j_obj.getProperty(key)
+ end
+ end
+ return event
+ end # def create_event
+
  private
  def handle_socket(socket, output_queue)
  begin
  # JRubyObjectInputStream uses JRuby class path to find the class to de-serialize to
  ois = JRubyObjectInputStream.new(java.io.BufferedInputStream.new(socket.to_inputstream))
  loop do
- # NOTE: log4j_obj is org.apache.log4j.spi.LoggingEvent
- log4j_obj = ois.readObject
- event = LogStash::Event.new("message" => log4j_obj.getRenderedMessage)
- decorate(event)
+ event = create_event(ois.readObject)
  event["host"] = socket.peer
- event["path"] = log4j_obj.getLoggerName
- event["priority"] = log4j_obj.getLevel.toString
- event["logger_name"] = log4j_obj.getLoggerName
- event["thread"] = log4j_obj.getThreadName
- event["class"] = log4j_obj.getLocationInformation.getClassName
- event["file"] = log4j_obj.getLocationInformation.getFileName + ":" + log4j_obj.getLocationInformation.getLineNumber
- event["method"] = log4j_obj.getLocationInformation.getMethodName
- event["NDC"] = log4j_obj.getNDC if log4j_obj.getNDC
- event["stack_trace"] = log4j_obj.getThrowableStrRep.to_a.join("\n") if log4j_obj.getThrowableInformation
-
- # Add the MDC context properties to '@fields'
- if log4j_obj.getProperties
- log4j_obj.getPropertyKeySet.each do |key|
- event[key] = log4j_obj.getProperty(key)
- end
- end
-
+ decorate(event)
  output_queue << event
  end # loop do
  rescue => e
- @logger.debug("Closing connection", :client => socket.peer,
+ @logger.debug? && @logger.debug("Closing connection", :client => socket.peer,
  :exception => e)
  rescue Timeout::Error
- @logger.debug("Closing connection after read timeout",
+ @logger.debug? && @logger.debug("Closing connection after read timeout",
  :client => socket.peer)
  end # begin
  ensure
@@ -118,13 +122,9 @@ def readline(socket)
  def run(output_queue)
  if server?
  loop do
- # Start a new thread for each connection.
  Thread.start(@server_socket.accept) do |s|
- # TODO(sissel): put this block in its own method.
-
- # monkeypatch a 'peer' method onto the socket.
  s.instance_eval { class << self; include ::LogStash::Util::SocketPeer end }
- @logger.debug("Accepted connection", :client => s.peer,
+ @logger.debug? && @logger.debug("Accepted connection", :client => s.peer,
  :server => "#{@host}:#{@port}")
  handle_socket(s, output_queue)
  end # Thread.start
@@ -133,7 +133,7 @@ def run(output_queue)
  loop do
  client_socket = TCPSocket.new(@host, @port)
  client_socket.instance_eval { class << self; include ::LogStash::Util::SocketPeer end }
- @logger.debug("Opened connection", :client => "#{client_socket.peer}")
+ @logger.debug? && @logger.debug("Opened connection", :client => "#{client_socket.peer}")
  handle_socket(client_socket, output_queue)
  end # loop
  end

spec/inputs/log4j_spec.rb

@@ -10,4 +10,53 @@
  # register will try to load jars and raise if it cannot find jars or if org.apache.log4j.spi.LoggingEvent class is not present
  expect {input.register}.to_not raise_error
  end
+
+ context "reading general information from a org.apache.log4j.spi.LoggingEvent" do
+ let (:input) { LogStash::Plugin.lookup("input", "log4j").new("mode" => "client") }
+ let (:log_obj) {
+ org.apache.log4j.spi.LoggingEvent.new(
+ "org.apache.log4j.Logger",
+ org.apache.log4j.Logger.getLogger("org.apache.log4j.LayoutTest"),
+ 1426366971,
+ org.apache.log4j.Level::INFO,
+ "Hello, World",
+ nil
+ )
+ }
+
+ let (:log_obj_with_stacktrace) {
+ org.apache.log4j.spi.LoggingEvent.new(
+ "org.apache.log4j.Logger",
+ org.apache.log4j.Logger.getLogger("org.apache.log4j.LayoutTest"),
+ 1426366971,
+ org.apache.log4j.Level::INFO,
+ "Hello, World",
+ java.lang.IllegalStateException.new()
+ )
+ }
+
+ it "creates event with general information" do
+ subject = input.create_event(log_obj)
+ expect(subject["path"]).to eq("org.apache.log4j.LayoutTest")
+ expect(subject["priority"]).to eq("INFO")
+ expect(subject["logger_name"]).to eq("org.apache.log4j.LayoutTest")
+ expect(subject["thread"]).to eq("main")
+ expect(subject["message"]).to eq("Hello, World")
+ # checks locationInformation is collected, but testing exact values is not meaningful in jruby
+ expect(subject["class"]).not_to be_empty
+ expect(subject["file"]).not_to be_empty
+ expect(subject["method"]).not_to be_empty
+ end
+
+ it "creates event without stacktrace" do
+ subject = input.create_event(log_obj)
+ expect(subject["stack_trace"]).to be_nil
+ end
+
+ it "creates event with stacktrace" do
+ subject = input.create_event(log_obj_with_stacktrace)
+ #checks stack_trace is collected, exact value is too monstruous
+ expect(subject["stack_trace"]).not_to be_empty
+ end
+ end
 end