Module: Hyperion::WorkerHealth

Defined in:
lib/hyperion/worker_health.rb

Overview

Measures a worker process’s resident set size (RSS) in MiB. Cross-platform: uses /proc/<pid>/statm on Linux (zero subprocess) and ‘ps -o rss= -p <pid>` everywhere else (macOS, BSD).

Class Method Summary collapse

Class Method Details

.rss_mb(pid) ⇒ Object

Returns the worker’s RSS in MiB, or nil if it can’t be read (process gone, ps not available, /proc not mounted). Callers must handle nil gracefully — health checks must never crash the supervisor.



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# File 'lib/hyperion/worker_health.rb', line 13

def rss_mb(pid)
  if File.readable?("/proc/#{pid}/statm")
    # statm fields are in pages; column index 1 is "resident".
    # PAGE_SIZE = 4096 on x86_64 / aarch64 Linux.
    contents = File.read("/proc/#{pid}/statm")
    pages = contents.split.fetch(1).to_i
    bytes = pages * 4096
    bytes / 1024 / 1024
  else
    # Fallback: ps emits RSS in KiB.
    out = `ps -o rss= -p #{pid} 2>/dev/null`
    kib = out.strip.to_i
    return nil if kib.zero?

    kib / 1024
  end
rescue StandardError
  nil
end