TreeFallingInTheWoods

Problem: Running a system call from an object in a Rails thread - if the process outputs to stderr or stdout, and you have not set up IO buffers to hold the bytes, the process will stall until it times out. e.g.

def publish
...
  @gallery = fetch_gallery()
  system("script/generate gallery_creator #{gallery.id}") 
...
end

If the generator outputs to stderr or stdout, the process will stall. The solution is Open3 (thanks lachie).

 
def publish
...
  @gallery = fetch_gallery()
    Open3.popen3("script/generate gallery_creator #{@gallery.id}") do |stdin, stdout, stderr|
      logger.info("stdout - #{stdout.readlines}")
      logger.info("stderr - #{stderr.readlines}")
    end

...
end