Module: SemanticLogger::CoreExt::Process

Defined in:
lib/semantic_logger/core_ext/process.rb

Overview

Reopen all appenders in the child process after a fork.

Prepended onto Process.singleton_class when Semantic Logger is loaded. Enabled by default; opt out with SemanticLogger.reopen_on_fork = false.

Process._fork (Ruby 3.1+) is the single method that every fork path routes through (Kernel#fork, Process.fork, IO.popen, Kernel#system, and backticks), so overriding it covers them all with one hook.

Note: both _fork and daemon must be overridden to reliably restart the appender thread, since Process.daemon does not route through _fork (https://bugs.ruby-lang.org/issues/18911). Do not collapse this down to only _fork.

Instance Method Summary collapse

Instance Method Details

#_fork ⇒ Object

_fork runs in both the parent and the child. It returns 0 in the child and the child's pid in the parent, so only reopen in the child. Reopening in the parent would needlessly recreate its queue and worker thread, risking the loss of messages still on the queue.



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# File 'lib/semantic_logger/core_ext/process.rb', line 21

def _fork
  child_pid = super
  SemanticLogger.reopen if child_pid.zero? && SemanticLogger.reopen_on_fork?
  child_pid
end

#daemon ⇒ Object

Process.daemon does not route through _fork, so reopen explicitly. Once it returns, the caller is running as the daemon (child) process.



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# File 'lib/semantic_logger/core_ext/process.rb', line 29

def daemon(...)
  super.tap { SemanticLogger.reopen if SemanticLogger.reopen_on_fork? }
end