Module: RobotLab::To::AtomicFile

Defined in:
lib/robot_lab/to/atomic_file.rb

Overview

Crash-safe writes for run state (notes.md and friends).

An overnight run rewrites its state every iteration; a crash or kill mid-write must not leave a truncated file (notes.md is re-injected into the next robot's prompt). The pattern: serialize writers with an flock, stage the full content in a sibling temp file, fsync it, atomically rename it over the target, then fsync the directory. A crash at any point leaves either the previous complete file or the new complete file -- never a torn write.

Class Method Summary collapse

Class Method Details

.append(path, text) ⇒ Object

Atomically append text to path (read-modify-write under lock).



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# File 'lib/robot_lab/to/atomic_file.rb', line 26

def append(path, text)
  path = Pathname.new(path)
  path.parent.mkpath
  with_lock(path) do
    existing = path.exist? ? path.read : +""
    replace(path, existing + text.to_s)
  end
end

.write(path, content) ⇒ Object

Atomically replace path with content.



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# File 'lib/robot_lab/to/atomic_file.rb', line 19

def write(path, content)
  path = Pathname.new(path)
  path.parent.mkpath
  with_lock(path) { replace(path, content.to_s) }
end