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

Question

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.

score 9 · Answer 1 · answered Sep 03 '12 at 06:19

9

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

answered Sep 03 '12 at 06:19

Tema Bolshakov

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The cleanest of the dirty. Thanks! – Josh M. Feb 20 '14 at 02:53

Frederick Cheung · Accepted Answer · 2014-09-15T13:42:35.500

8

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)

edited Sep 15 '14 at 13:42

answered Sep 03 '12 at 11:09

Frederick Cheung

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That's actually promising. Thanks! – Remus Rusanu Sep 03 '12 at 11:14
This doesn't seem to be working for me in Rails 4 with passenger. – Dan Herman Sep 15 '14 at 13:40
The constant to check seems to be ::PhusionPassenger now – Frederick Cheung Sep 15 '14 at 13:42
@DanHerman looks like either the constant to check changed or it was a typo all along – Frederick Cheung Sep 15 '14 at 13:51

score 7 · Answer 3 · edited May 23 '17 at 11:45

7

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

edited May 23 '17 at 11:45

Community

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answered Apr 15 '15 at 11:52

Vishal

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score 0 · Answer 4 · answered Aug 23 '12 at 09:35

0

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

Something like:

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

answered Aug 23 '12 at 09:35

severin

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it would have to work in production too, when running under Apache – Remus Rusanu Aug 23 '12 at 10:05

score 0 · Answer 5 · answered Aug 23 '12 at 10:34

0

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

answered Aug 23 '12 at 10:34

Stefan

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I would still need to know when to start the daemon and when not – Remus Rusanu Aug 24 '12 at 07:45

score 0 · Answer 6 · answered Sep 01 '12 at 09:25

0

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.

answered Sep 01 '12 at 09:25

Gordon Wilson

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Yes it will. When you run rails server `ps aux | grep rails` will contain something like `remus 18454 0.0 0.8 2515572 65968 s000 S+ 11:10AM 0:01.51 /Users/remus/.rvm/rubies/ruby-1.9.3-p125/bin/ruby script/rails server` – Gordon Wilson Sep 01 '12 at 18:13

score 0 · Answer 7 · edited Oct 15 '21 at 09:39

0

In addition to a great answer by Frederick Cheung above, there can be some other "footprints" in actual process environment. Eg. Phusion Passenger adds certain variables to ENV such as:

PASSENGER_APP_ENV
IN_PASSENGER
PASSENGER_SPAWN_WORK_DIR
PASSENGER_USE_FEEDBACK_FD

Web servers typically can also set SERVER_SOFTWARE variable eg.:

SERVER_SOFTWARE=nginx/1.15.8 Phusion_Passenger/6.0.2

edited Oct 15 '21 at 09:39

Dharman

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answered Oct 15 '21 at 09:33

pokrovskyy

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

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