fluent-cat: support to send event time in specified timestamp

It is aimed to help to send specific timestamp event easily.

Signed-off-by: Kentaro Hayashi <hayashi@clear-code.com>

lib/fluent/command/cat.rb

@@ -35,6 +35,7 @@
 message_key = 'message'
 time_as_integer = false
 retry_limit = 5
+fake_time = nil
 
 op.on('-p', '--port PORT', "fluent tcp port (default: #{port})", Integer) {|i|
   port = i
@@ -80,6 +81,10 @@
   retry_limit = n
 }
 
+op.on('--fake-time TIME_STRING', "Specify the time expression string (default: nil)") {|v|
+  fake_time = v
+}
+
 singleton_class.module_eval do
   define_method(:usage) do |msg|
     puts op.to_s
@@ -134,7 +139,7 @@ def run
     end
   end
 
-  def initialize(tag, connector, time_as_integer: false, retry_limit: 5)
+  def initialize(tag, connector, time_as_integer: false, retry_limit: 5, fake_time: nil)
     @tag = tag
     @connector = connector
     @socket = false
@@ -148,6 +153,7 @@ def initialize(tag, connector, time_as_integer: false, retry_limit: 5)
     @retry_wait = 1
     @retry_limit = retry_limit
     @time_as_integer = time_as_integer
+    @fake_time = fake_time
 
     super()
   end
@@ -166,7 +172,11 @@ def write(record)
       end
     end
 
-    time = Fluent::EventTime.now
+    time = if @fake_time
+             Fluent::EventTime.parse(@fake_time)
+           else
+             Fluent::EventTime.now
+           end
     time = time.to_i if @time_as_integer
     entry = if secondary_record?(record)
               # Even though secondary contains Fluent::EventTime in record,
@@ -309,7 +319,7 @@ def abort_message(time, record)
   }
 end
 
-w = Writer.new(tag, connector, time_as_integer: time_as_integer, retry_limit: retry_limit)
+w = Writer.new(tag, connector, time_as_integer: time_as_integer, retry_limit: retry_limit, fake_time: fake_time)
 w.start
 
 case format

test/command/test_cat.rb

@@ -96,4 +96,33 @@ def test_cat_secondary_file
                    [d.events.size, event.first, event.last])
     end
   end
+
+  sub_test_case "fake-time" do
+    def test_without_fake_time
+      fake_event_time = Fluent::EventTime.parse("2021-01-02 13:14:15.0+09:00")
+      d = create_driver
+      d.run(expect_records: 1) do
+        Open3.pipeline_w("ruby #{FLUENT_CAT_COMMAND} --port #{@port} tag") do |stdin|
+          stdin.puts('{"key":"value"}')
+          stdin.close
+        end
+      end
+      event = d.events.first
+      assert_equal([1, "tag", true, @record],
+                   [d.events.size, event.first, event[1] > fake_event_time, event.last])
+    end
+
+    def test_with_fake_time
+      fake_time = "2021-01-02 13:14:15.0+00:00"
+      d = create_driver
+      d.run(expect_records: 1) do
+        Open3.pipeline_w("ruby #{FLUENT_CAT_COMMAND} --port #{@port} --fake-time '#{fake_time}' tag") do |stdin|
+          stdin.puts('{"key":"value"}')
+          stdin.close
+        end
+      end
+      assert_equal([1, ["tag", Fluent::EventTime.parse(fake_time), @record]],
+                   [d.events.size, d.events.first])
+    end
+  end
 end