Duplicated request info log in Rails 5 server only app - ruby-on-rails

Question

I have a Rails 5.2.3 application with Ruby 2.4.5.
I found a weird issue that the request info are logged twice in stdout.
Here is the log config in config/environments/product.rb
config.logger = ActiveSupport::TaggedLogging.new(ActiveSupport::Logger.new(STDOUT))
config.log_tags = [ lambda {|req| "#{req.cookie_jar["_session_id"]}" }, :remote_ip, :uuid ]
Supposedly it will tag every log with the remote ip and request uuid, and it does for most of logs, except there is a weird additional log for the request. In following example, the last line is a duplicated log for the request without the tag:
[INFO] [2019-10-28 06:11:45 UTC] [127.0.0.1] [f6de1900-a7e5-4486-8b73-7095d0cacb35] Started GET "/api/v1/nodes?pageSize=20&pageNumber=1" for 127.0.0.1 at 2019-10-28 06:11:45 +0000
[INFO] [2019-10-28 06:11:45 UTC] [127.0.0.1] [f6de1900-a7e5-4486-8b73-7095d0cacb35] Processing by Api::V1::NodesController#index as XML
...
...
[INFO] [2019-10-28 06:20:02 UTC] [127.0.0.1] [993e0db4-3995-41ef-851a-bfea1bc25781] Completed 200 OK in 1084ms (Views: 341.9ms | ActiveRecord: 150.6ms)
127.0.0.1 - - [28/Oct/2019:06:20:02 +0000] "GET /api/v1/nodes?pageSize=20&pageNumber=1 HTTP/1.1" 200 - 1.1347
I checked configurations, there is no any other logger configured.
The consequence is that there is a timer in client side to check notification status by every 5 seconds. I added a log silencer to avoid log such request:
# config/application.rb
config.middleware.insert_before Rails::Rack::Logger, LogSilencer, silenced: /notification_messages/
# lib/log_silencer.rb
class LogSilencer
def initialize(app, opts = {})
#app = app
#silenced = opts.delete(:silenced)
end
def call(env)
if #silenced.match(env['PATH_INFO'])
Rails.logger.silence do
#app.call(env)
end
else
#app.call(env)
end
end
end
It does avoid logging from the tagged logger, but the duplicated request logs are still there, then the stdout is full of this request
127.0.0.1 - - [28/Oct/2019:07:04:21 +0000] "GET /api/v1/notification_messages/to_notify HTTP/1.1" 200 - 0.0118
127.0.0.1 - - [28/Oct/2019:07:04:26 +0000] "GET /api/v1/notification_messages/to_notify HTTP/1.1" 200 - 0.0140
127.0.0.1 - - [28/Oct/2019:07:04:31 +0000] "GET /api/v1/notification_messages/to_notify HTTP/1.1" 200 - 0.0137
127.0.0.1 - - [28/Oct/2019:07:04:36 +0000] "GET /api/v1/notification_messages/to_notify HTTP/1.1" 200 - 0.0149
...
Spent a whole day try to find out who generated this log, but no any clue...
Would like to ask for help on how to turn off this log so make the log data clear...
Thanks!

Answer 1

Seems the logs come from the web server used when up the Rails app.
When use WEBrick, the log is like
=> Booting WEBrick
=> Rails 5.2.3 application starting in development on http://localhost:4000
=> Run `rails server -h` for more startup options
[2019-10-30 07:01:13] INFO WEBrick 1.3.1
[2019-10-30 07:01:13] INFO ruby 2.4.5 (2018-10-18) [x86_64-linux]
[2019-10-30 07:01:13] INFO WEBrick::HTTPServer#start: pid=5812 port=4000
127.0.0.1 - - [30/Oct/2019:07:01:17 UTC] "GET /test HTTP/1.1" 304 0
- -> /test
When use unicorn, the log is like:
I, [2019-10-30T07:02:47.626962 #5956] INFO -- : Refreshing Gem list
I, [2019-10-30T07:02:48.289373 #5956] INFO -- : listening on addr=0.0.0.0:4000 fd=17
I, [2019-10-30T07:02:48.393598 #5956] INFO -- : master process ready
I, [2019-10-30T07:02:48.394853 #5965] INFO -- : worker=0 ready
I, [2019-10-30T07:02:48.399878 #5968] INFO -- : worker=1 ready
127.0.0.1 - - [30/Oct/2019:07:02:52 +0000] "GET /test HTTP/1.1" 304 - 0.0724
I can find that the request log format is a bit different (the time zone info, the time consumed etc).
I use Unicorn, its logger by default uses stderr, but seems the logger configuration does not work
logger Logger.new("#{rails_root}/log/unicorn.log")
so I have to set the stderr path
stderr_path "#{rails_root}/log/unicorn.stderr.log
Then the request logs are in the unicorn.stderr.log file, and STDOUT are the rails app logs.
But still dont know how to turn it off since it is a kind of duplicated and useless log...