discourse/lib/demon
Alan Guo Xiang Tan 23c38cbf11
DEV: Log Unicorn worker timeout backtraces to `Rails.logger` (#27257)
This commit introduces the following changes:

1. Introduce the `SignalTrapLogger` singleton which starts a single
   thread that polls a queue to log messages with the specified logger.
   This thread is necessary becasue most loggers cannot be used inside
   the `Signal.trap` context as they rely on mutexes which are not
   allowed within the context.

2. Moves the monkey patch in `freedom_patches/unicorn_http_server_patch.rb` to
   `config/unicorn.config.rb` which is already monkey patching
   `Unicorn::HttpServer`.

3. `Unicorn::HttpServer` will now automatically send a `USR2` signal to
   a unicorn worker 2 seconds before the worker is timed out by the
   Unicorn master.

4. When a Unicorn worker receives a `USR2` signal, it will now log only
   the main thread's backtraces to `Rails.logger`. Previously, it was
   `put`ing the backtraces to `STDOUT` which most people wouldn't read.
   Logging it via `Rails.logger` will make the backtraces easily
   accessible via `/logs`.
2024-06-03 12:51:12 +08:00
..
base.rb DEV: Log Unicorn worker timeout backtraces to `Rails.logger` (#27257) 2024-06-03 12:51:12 +08:00
email_sync.rb DEV: Log Unicorn worker timeout backtraces to `Rails.logger` (#27257) 2024-06-03 12:51:12 +08:00
rails_autospec.rb
sidekiq.rb DEV: Log Unicorn worker timeout backtraces to `Rails.logger` (#27257) 2024-06-03 12:51:12 +08:00