EC
SignalException
RubyFATALCommonSystem

OS signal received by the process

Quick Answer

Use Signal.trap to handle specific signals gracefully; do not suppress SignalException in application rescue blocks.

What this means

Raised when the Ruby process receives an OS signal. Interrupt (Ctrl+C, SIGINT) is the most common subclass. Like SystemExit, SignalException is under Exception, not StandardError.

Why it happens
  1. 1Pressing Ctrl+C which sends SIGINT
  2. 2kill -TERM sent to the process from the OS or process manager

Fix

Trap specific signals for graceful shutdown

Trap specific signals for graceful shutdown
Signal.trap('TERM') do
  puts 'SIGTERM received — shutting down'
  $shutdown = true
end

loop do
  break if $shutdown
  process_next_job
end

Why this works

Signal.trap registers a handler that runs in the main thread when the signal is received.

Code examples
Interrupt from Ctrl+Cruby
begin
  loop { sleep 0.1 }
rescue Interrupt
  puts "
Interrupted — exiting cleanly"
end
Checking ancestryruby
Interrupt < SignalException  # => true
SignalException < Exception  # => true
Trap SIGINTruby
Signal.trap('INT') { puts 'Caught SIGINT'; exit }
Sources
Official documentation ↗

Ruby Core Documentation

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