Deploying on Heroku

[garyfoster]

I implemented a routine to listen via the event streaming and it works fine if I run it on the rails console, or if I add the code to a rails initializer. Any hints on how to set this up to run as a daemon when deploying to heroku, preferably on a separate dyno from the main web dyno?

[godfat]

Create a standalone script (e.g. daemon.rb), something like this:

# Or change to where you could find your Rails environment
require_relative 'config/environment'

thread = Thread.new do
  Thread.current.abort_on_exception = true

  # Of course you should write it more formally, here's just the idea
  $start = true

  # Use your event stream setup somewhere
  event_stream.start
  sleep(1) while $start # sleep forever while we're running
  event_stream.close
  event_stream.wait # shutdown cleanly
end

rd, wr = IO.pipe

%w[INT TERM].each do |sig|
  Signal.trap(sig) do
    wr.puts # unblock the main thread
  end
end

rd.gets # block main thread until INT or TERM received
$start = false # shutting down
thread.join # wait for the thread to stop cleanly

Or maybe you could just do it simple if you don't need to do the other stuffs.

# Or change to where you could find your Rails environment
require_relative 'config/environment'

# Use your event stream setup somewhere
event_stream.start

rd, wr = IO.pipe

%w[INT TERM].each do |sig|
  Signal.trap(sig) do
    wr.puts # unblock the main thread
  end
end

rd.gets # block main thread until INT or TERM received
event_stream.close
event_stream.wait # shutdown cleanly

And finally put it in your Procfile like:

firebase_daemon: ruby -Ilib daemon.rb

[garyfoster]

Worked great, thanks!