Detect if application was started as HTTP server or not (rake task, rconsole etc)

问题

I'm using EventMachine and Monetarily to start e TCP server along with my rails application. This is started from config/initializers/momentarily.rb.

My problem is that it starts also when I run rake tasks, like db:migrate. I only want it to start when when I start the HTTP server. Environments won't help, since both the server start and rake tasks are under Development environment. Is there a way of knowing that the application is running the HTTP server as opposed to anything else? Note that is not only rake tasks, the EM starts also if I run the rails console, which is again something not desirable for my case.

回答1:

There's not a great way of doing this that I know of. You could copy newrelic's approach (check discover_dispatcher in local_environment.rb) which basically has a list of heuristics used to detect if it is running inside passenger, thin, etc.

For passenger it checks

defined?(::PhusionPassenger)

for thin it checks

if defined?(::Thin) && defined?(::Thin::Server)

回答2:

unless File.basename($0) == "rake" && ARGV.include?("db:migrate")
  # you are not in rake db:migrate
end

回答3:

Set an environment variable in config.ru file, and use it anywhere in the code to detect if it's executed using a rails server command only.

For e.g.

• File: config.ru

  ENV['server_mode'] = '1'
  

And using it somewhere as:

• File: config/environment.rb

  Thread.new { infinite_loop! }.join if ENV['server_mode'] = '1'
  

---

Reference: Answer

回答4:

Maybe you can implement a switch in the initializer based on ARGV?

Something like:

if ARGV.join(' ').match /something/
  # your initializer code here
end

回答5:

Don't start that other server from an initializer. Create a daemon in script/momentarily and start it from within your app.

回答6:

After your application launches, you could have it shell out to check ps. If ps shows that the HTTP server is running and the running HTTP server has the same pid as your application (check the pid by inspecting $$), then you could launch the TCP server.

来源：https://stackoverflow.com/questions/12088025/detect-if-application-was-started-as-http-server-or-not-rake-task-rconsole-etc